Pandiya's Blog

working with SQLite in WPF

2010-10-07T10:18:00.000+05:30

You can use SQLite in WPF the same way you would use SQL Server, Oracle or any other database -- via ADO.NET or (better) via an object-relational mapper. An ORM is probably a better option because a good ORM will handle things like property change notifications (critical for data binding) for you.

The basic technique you are looking for is to define a model which you will load and save via the ORM, and databind your UI to using data binding. (The full version of this pattern is called model-view-viewmodel or MVVM but as a beginner you probably want to focus on the basics of creating and binding to a domain model first and tackle the more complex aspects of MVVM later.)

For more on SQLite visit http://sqlite.phxsoftware.com/

What is the best ORM for .NET ?

2010-10-07T10:05:00.000+05:30

There are lots of very good ORMs approaching the subject with different philosophies.
None are perfect through and all tend to become complex as soon as you stray from their golden path (and sometimes even when you stick to it).

What you should ask yourself when selecting an ORM:

What does it need to do for you?
If you already have a set of requirements for your application, then you should select the ORM that better matches these rather than an hypothetical 'best'.
Is your data shared or just local?
A lot of the hairiness in ORM is caused by how they handle concurrency and changes to the data in the database when multiple users are holding a versions of the same data.
If your datastore is for a single-user, then most ORMs will do a good job. However, ask yourself some hard questions in a multi-user scenario: how is locking handled? What happens when I delete an object? How does it affects other related objects? Is the ORM working close to the metal of the backend or is it caching a lot of data (improving performance at the expense of increasing the risk of staleness).
Is the ORM well adapted for your type of application? A particular ORM may be hard to work with (lots of performance overhead, hard to code) if it's a used in a service or sitting inside a web app. It may on the contrary be great for desktop apps.
Do you have to give up database-specific enhancements?
ORMs tend to use the lowest-common denominator set of SQL to ensure they work with lots of different database backend.
All ORMs will compromise on available features (unless they specifically target a single backend) but some will allow you to implement additional behaviours to exploit specific enhancements available in your chosen backend.
A typical db-specific enhancement is Full-Text search capabilities for instance; make sure your ORM provides you with a way to access these features if you need them.
How does the ORM manages changes in the data model?
Some can update the DB automatically within a certain measure, other don't do anything and you'll have to do the dirty work yourself; other provide a framework for handling change that lets you control database updates.
Do your mind to couple your application to the ORM's objects or do you prefer to handle POCOs and user an adapter for persistence?
The former is usually simple to handle but create dependencies on your ORM-specific data objects everywhere, the latter is more flexible, at the cost of a bit more code.
Will you ever need to transfer your objects remotely?
Not all ORMs are equal when it comes to fetching objects from a remote server, look closely at what is possible or impossible to do. Some are efficient, others not.
Is there someone you can turn to for help?
Is there good commercial support? How big and active is the community around the project?
What are the issues existing users are having with the product?
Do they get quick solutions?

A few ORMs that I looked at:

XPO
From developer Express: is small and simple, code-centric. They use it for their application frameworkeXpressApp.
NHibernate
Is free, but the learning curve is rather steep. Lots of goodies but it's hard to find what is really relevant sometimes in all the fragmented documentation.
LLBLGen Pro
very mature project, not the simplest but a lot of thought has been put into it.
Entity Framework
Still a bit early IMHO. It's promising, but there are some basic stuff that other ORMs provide that are just now being tackled (auto-generating DB from code for instance).
DataObject.Net
Looks promising but is also a bit new to risk an important project on it IMHO. Quite active though.

There are many others of course.

You can have a look at the controversial site ORM Battle that lists some performance benchmarks, although you have to be aware that raw speed is not necessarily the most important factor for your project and that the producers of the website is DataObject.Net.

What coworker habit do you find most annoying?

2010-10-06T15:05:00.000+05:30

As I write this, there's a guy in the office clipping his nails at his desk.

Ques : What personal habits do your coworkers exhibit that drive you nuts and how do you deal with them? Do you quietly stew, adjust your attitude, or approach them about it?

Ans: http://tinyurl.com/2cw4w3s

What's your experience with female programmers?

2010-10-06T14:53:00.000+05:30

I was going through a programmers Q&A and i saw this question. Do a read of it http://tinyurl.com/3ayjdt6

Sqlite with asp.net MVC

2010-09-29T16:28:00.000+05:30

Using Sqlite with asp.net MVC web application
Visual Studio 2008 integrates Sql server 2008 express nicely into App_Data folder. You just create the database using Server Explorer, and it inserts the connection string into web.config for you. I used it when I worked on my toy project – ToastManager. I finished coding and testing on my machine and deployed it to an integration server which belongs to my SCRUM team.

A problem, as usual, arose on the integration box. My windows login had sysadmin access to my local Sql Server express, but the process that runs ToastManager did not on the box.

I blindly thought that Sql Server express is a stand-alone DB and it can be deployed together with the applicaiton. It was misunderstanding. Sql Server Express is still a server application that needs to be installed on a remote machine. I looked for an alternative and soon found that many people useSqlite.

Sqlite is an open source database and people testify that it is really fast. In order to use with .Net, you need to install System.Data.SQLite, which is another open source ADO.NET provider for SQLite database engine.

Once you download Sqlite, you can use its own command-prompt based tool, but probably, your first reaction is to try to find some GUI management tool. Fortunately, there is one too. It is FireFox Add-on: SQLite Manager.

So, to summarise, you need to have 3 programs to use SQLite. SQLite,System.Data.SQLite, and SQLite Manager.

Just now started my first sample will update you on that in the posts to come in future...

Simple reusable clear form function in asp.net using jquery?

2010-09-24T10:46:00.000+05:30

I ve created a function which clears the form without writing much javascript code.

$.fn.clearForm = function() {
return this.each(function() {
    var type = this.type, tag = this.tagName.toLowerCase();
    if (tag == 'form') {
        $('td.status', this).empty();
        return $(':input', this).clearForm();
    }
    if (type == 'text' || type == 'password' || tag == 'textarea' || tag ==
                                 'label')
        this.value = '';
    else if (type == 'checkbox' )
        this.checked = false;
    else if (tag == 'select')
        this.selectedIndex = -1;

});
};

and just call this as,

function clearaddform() {
    $("#aspnetForm").clearForm();
  }

and now you can just call clearaddform function from your button.

The Twitter hack: how it started and how it worked

2010-09-22T18:08:00.000+05:30

I was shocked while i was going through this article about the Twitter Hack. It is still unbelievable that twitter has been hacked just due to XSS "cross-site scripting".

[Fluent nHibernate vs Entity framework] Which to choose for ORM?

2010-09-22T11:01:00.000+05:30

I ve been working with Fluent nHibernate and it ships really well with my asp.net mvc web application pretty well. Just yesterday had a look at Microsoft's Entity Framework and it looks like a good competitor for fluent nhibernate.. I was searching through the web and i found this wonderful article,

which-orm-linq-to-sql-entity-framework-llblgen-nhibernate?

What is a “web service” in plain english?

2010-09-01T18:08:00.002+05:30

I've been reading about "web services" here on SO, on Wikipedia, Google, etc and I don't quite understand what they are. What is the plain english definition/description?

If I make a simple website using PHP that just, say, prints a random integer to the page... is this a "web service"? If not, why not?

A simple definition: A web service is a function that can be accessed by other programs over the web (Http). To clarify a bit, when you create a website in PHP that outputs HTML its target is the browser and by extension the human being reading the page in the browser. A web service is not targeted at humans but rather at other programs.

So your PHP site that generates a random integer could be a web service if it outputs the integer in a format that may be consumed by another program. It might be in an XML format or another format, as long as other programs can understand the output.

The full definition is obviously more complex but you asked for plain English.

What is cool about c# generics, why use them?

2010-08-31T12:26:00.000+05:30

I thought I'd offer this softball to whomever would like to hit it out of the park. What are generics, what are the advantages of generics, why, where, how should I use them?

Allows you to write code/use library methods which are type-safe, i.e. a List<string> is guaranteed to be a list of strings.
As a result of generics being used the compiler can perform compile-time checks on code for type safety, i.e. are you trying to put an int into that list of strings? Using an ArrayList would cause that to be a less transparent runtime error.
Faster than using objects as it either avoids boxing/unboxing (where .net has to convert value types to reference types or vice-versa) or casting from objects to the required reference type.
Allows you to write code which is applicable to many types with the same underlying behaviour, i.e. a Dictionary<string, int> uses the same underlying code as a Dictionary<DateTime, double>; using generics, the framework team only had to write one piece of code to achieve both results with the aforementioned advantages too.

What's your choice for your next ASP.NET project: WebForms or MVC?

2010-08-31T10:47:00.000+05:30

Let's say that you will start a new Asp.Net web site/application tomorrow. What your choice between WebForms and MVC, and why?

I'd choose asp.net MVC for the following reasons:

ASP.NET MVC has borrowed so much from Rails that it feels like a direct port in some ways (and that's a good thing in my mind).
AJAX is important, but I hate the Microsoft "Atlas" approach to AJAX (whatever the product name is these days). If you're going to do AJAX, you need to understand the HTML and the JavaScript. Frameworks that hide that from you are hurting you more than they are helping you (IMO).
JQuery has taken over the world it seems in terms of JavaScript frameworks. ASP.net MVC is well-integrated with it. I want to learn it, so there's great alignment here.
The whole "control" model is a neat idea, but it is more complicated than it appears on the surface. For example, look around on SO for questions about how a UserControl can find its highest level containing control and so forth. The control hierarchy abstraction has leaks in it. Grids are great if they do what you want out of the box, but it's very very hard to customize them to do something they weren't made to do. And the best grid controls on the market (the ones that are highly customizable) are large, bloated, overly complicated beasts. Maybe that shows us that we should drop back down to HTML and let loops in our views do that kind of thing for us.
I believe I can build complete, beautiful apps in ASP.net MVC much faster than in ASP.Net (and I've got some years of ASP.Net under my belt). Look at StackOverflow ... built quickly on ASPMVC with JQuery, and it's fast, scalable and a joy to use IMO.
Oh, and it's completely open source! It is ok to read the source code, blog about it, and even modify then redistribute it!

So be wise in choosing it...

Latitude and Longitude Lookup with jQuery, C#, ASP.NET MVC

2010-08-30T15:14:00.000+05:30

This asp.net mvc controller action returns a place latitude and longitude based on zipcode and country name,

public ActionResult LookupCoordinates(string Zip, string Country)
{
    string Lat = "";
    string Lon = "";
    string PostUrl = "http://ws.geonames.org/postalCodeSearch?postalcode=" + Zip + "&maxRows=10&country=" + Country;
    WebResponse webResponse = webRequest.GetResponse();
    if (webResponse == null)
    { }
    else
    {
        StreamReader sr = new StreamReader(webResponse.GetResponseStream());
        string Result = sr.ReadToEnd().Trim();
        if (Result != "")
        {
            // Load the response into an XML doc
            XmlDocument xdoc = new XmlDocument();
            xdoc.LoadXml(Result);
            //  Navigate to latitude node
            XmlNodeList name = xdoc.GetElementsByTagName("lat");
            if (name.Count > 0)
            {
                Lat = name[0].InnerText;
            }
            //  Navigate to longitude node
            name = xdoc.GetElementsByTagName("lng");
            if (name.Count > 0)
            {
                 Lon = name[0].InnerText;
            }
        }
    }
    return Json(Lat + "," + Lon);
}

and the jquery function for implementing this would be,

function LookupCoordinates(zip) {
        $.post("/Home/LookupCoordinates",
        { Zip: zip, Country: "US" },
        function(data) {
            var result = eval('(' + data + ')');
            var coordinates = result.split(",");
            $("#Lat").val(coordinates[0]);
            $("#Lon").val(coordinates[1]);
        });
    }

Change contry to IN for india...

Images in asp.net performance booster web config setting...

2010-08-26T18:18:00.000+05:30

If your asp.net website deals with images just do this in your web.config file and see the performance and no drawbacks of doing this.

Under system.webServer in web.config set for example

<caching>
            <profiles>
                <add extension=".png" policy="CacheUntilChange" kernelCachePolicy="CacheUntilChange" location="Any" />
                <add extension=".jpg" policy="CacheUntilChange" kernelCachePolicy="CacheUntilChange" location="Any" />
                <add extension=".gif" policy="CacheUntilChange" kernelCachePolicy="CacheUntilChange" location="Any" />
            </profiles>
        </caching>

Twitter like notification bar in jquery

2010-07-23T10:23:00.000+05:30

Just designed a twitter like notification bar in jquery... See it in action demo here...

Just add the following jquery,

   $(document).ready(function() {
   var $alertdiv = $('<div id = "alertmsg"/>');
  $alertdiv.text("Welcome to twitter");
  $alertdiv.bind('click', function() {
  $(this).slideUp(200);
  });
  $(document.body).append($alertdiv);
  $("#alertmsg").slideDown("slow");
  setTimeout(function() { $alertdiv.slideUp(200) }, 3000);
  });

Css:

   #alertmsg
  {
  font-family:Arial,Helvetica,sans-serif;
   font-size:135%;
   font-weight:bold;
  overflow: hidden;
  width: 100%;
  text-align: center;
  position: absolute;
  top: 0;
  left: 0;
  background-color: #333F31;
  height: 20;
  color: #F3FDED;
  font: 20px/40px arial, sans-serif;
  opacity: .9;
  display:none;
}

Simple Jquery Dropdown menu...

2010-07-22T10:41:00.001+05:30

I ve designed a simple jquery dropdown Menu without using any jquery menu plugins....

<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
   <title></title>
   <script type="text/javascript" src="http://code.jquery.com/jquery-1.4.min.js"></script>
   <style type="text/css">
   ul, li{margin:0; padding:0; list-style:none;}
   /* Targeting both first and second level menus */
#Programming li { float: left; position: relative;font-family:Arial,Helvetica,sans-serif; }
#Programming li a { background: #f3fded; border: 3px solid #333f31; color: #333; display: block; margin: 0 5px 0 0; padding: 5px 8px;text-decoration:none; font-size:110%;font-weight:bold;}
#Programming li a:hover { background: #333f31;color:#fff; text-decoration: none; font-size:110%;font-weight:bold;}

/* Targeting the first level menu */
#Programming { display: block; height: 35px; padding: 10px 0; width: 700px; z-index: 100; position: absolute;}
#Programming > li > a { font-size:110%;font-weight:bold; }

/* Targeting the second level menu */
#Programming li ul { background: #f3fded; border: 3px solid #333f31; color: #333; display: none; margin: -3px 0 0 0; width: 105px; position: absolute; }
#Programming li ul li { width: 100% }
#Programming li ul li a { background: none; border: none; line-height: 30px; margin: 0; padding: 0 0 0 5px; text-decoration:none; font-size:110%; font-weight:bold;}
#Programming li ul li a:hover { background: #333f31;color:#fff;font-size:110%;font-weight:bold;}

/* A class of current will be added via jQuery */
#Programming li.current > a { background: #333f31;color:#fff; font-size:110%;font-weight:bold;}

/* CSS fallback */
#Programming li:hover > ul.child { display: block; }

   </style>
</head>
<body>
   <form id="form1" runat="server">
   <div>
   <div id="ProgMenu" style="padding-left: 45px;">
   <ul id="Programming">
   <li><a href="#">.net</a>
   <ul class="child">
   <li><a href="#">asp.net</a></li>
   <li><a href="#">WPF</a></li>
   <li><a href="#">Winforms</a></li>
   <li><a href="#">Silverlight</a></li>
   </ul>
   </li>
   <li><a href="#">java</a>
   <ul class="child">
   <li><a href="#">Struts</a></li>
   <li><a href="#">Spring</a></li>
   <li><a href="#">Hibernate</a></li>
   </ul>
   </li>
   </ul>
   </div>

   <script type="text/javascript">
   $(document).ready(function() {

   $("#Programming ul.child").removeClass("child");

   $("#Programming li").has("ul").hover(function() {
   $(this).addClass("current").children("ul").fadeIn();
   }, function() {
   $(this).removeClass("current").children("ul").stop(true, true).css("display", "none");
   });

   });
   </script>
   </div>
   </form>
</body>
</html>

See the Demo Simple jquery dropdown menu

Quartz.net with ASP.NET implementation...

2010-07-19T10:06:00.000+05:30

Just now finished my sample scheduled task with quartz.net in my asp.net web application.....

Here's a complete example how to do this using quartz.net. First of all, you have to create a class which implements the IJobinterface defined by quartz.net. This class is called by the quartz.net scheduler at tne configured time and should therefore contain your send mail functionality:

    using System;
    using System.Collections.Generic;
    using System.Linq;
    using System.Web;
    using System.IO;
    using Quartz;
    
    /// <summary>
    /// Summary description for SendMailJob
    /// </summary>
    public class SendMailJob : IJob
    {
        public void Execute(JobExecutionContext context)
        {
            WriteToFile();
        }
        private static void WriteToFile()
        {
            StreamWriter SW;
            SW = File.CreateText("C:\\Documents and Settings\\chendur\\Desktop\\samp.txt");
            SW.WriteLine("God is greatest of them all");
            SW.WriteLine("This is second line");
            SW.WriteLine(getIndianStandardTime());
            SW.Close();
        }
        public static DateTime getIndianStandardTime()
        {
            TimeZoneInfo IND_ZONE = TimeZoneInfo.FindSystemTimeZoneById("India Standard Time");
            return TimeZoneInfo.ConvertTimeFromUtc(DateTime.UtcNow, IND_ZONE);
        }
    }

Next you have to initialize the quartz.net scheduler to invoke your job once a day at 06:00. This can be done in Application_Start of global.asax:

<%@ Application Language="C#" %>
<%@ Import Namespace="Quartz"%>
<%@ Import Namespace="Quartz.Impl" %>

<script runat="server">

    void Application_Start(object sender, EventArgs e) 
    {
        ISchedulerFactory schedFact = new StdSchedulerFactory();
        // get a scheduler
        IScheduler sched = schedFact.GetScheduler();
        sched.Start();
        // construct job info
        JobDetail jobDetail = new JobDetail("mySendMailJob", typeof(SendMailJob));
        // fire every day at 06:00
        //Trigger trigger = TriggerUtils.MakeDailyTrigger(06, 00);
        SimpleTrigger trigger2 = new SimpleTrigger("myTrigger",
                                null,
                                DateTime.UtcNow,
                                null,
                                SimpleTrigger.RepeatIndefinitely,
                                TimeSpan.FromSeconds(60)); 
        //Trigger trigger = TriggerUtils.MakeHourlyTrigger();
        //// start on the next even hour
        //trigger.StartTimeUtc = TriggerUtils.GetEvenHourDate(DateTime.UtcNow);  
        //trigger.Name = "mySendMailTrigger";
        // schedule the job for execution
        sched.ScheduleJob(jobDetail, trigger2);
    }

That's it. Your job should be executed every day at 06:00. For testing, you can create a trigger which fires every minute (for example). Have a look at the method of TriggerUtils.

Get Indian Standard Time(IST) in c#

2010-07-16T11:18:00.000+05:30

When you are hosting you application to a production server outside india, its often we need indian time so i ve created a c# method which returns indian standard time from your server wherever it is located in india...

public DateTime getIndianStandardTime()
{
 TimeZoneInfo IND_ZONE=TimeZoneInfo.FindSystemTimeZoneById("India Standard Time");
 return TimeZoneInfo.ConvertTimeFromUtc(DateTime.UtcNow, IND_ZONE);}

Grant Mysql Database access...

2010-07-15T12:12:00.000+05:30

Today morning i was just looking around for a mysql query which grants me access to another database....

GRANT ALL PRIVILEGES ON dbname.* TO 'dbname'@'urpartnerip'    IDENTIFIED BY 'dbname' WITH GRANT OPTION;
GRANT SELECT ON mysql.proc TO 'dbname'@'urpartnerip' IDENTIFIED BY 'dbname'

Rich text editor for Asp.net...

2010-07-05T15:33:00.000+05:30

At last found a really cool rich text editor for asp.net....

Yahoooooooooo just completed my full sample on asp.net mvc & fluent nhibernate.....

2010-07-01T18:40:00.000+05:30

Really loved the way asp.net mvc works with fluent nhibernate... Yahoooooooooo just completed my full sample on asp.net mvc & fluent nhibernate.....

Rounded corners in IE without images amazing..

2010-07-01T17:36:00.002+05:30

Hai,
Just look at this IE rounded corners...

Best Programmer Joke i ve ever heard...

2010-06-29T12:35:00.000+05:30

A man flying in a hot air balloon suddenly realizes he’s lost. He reduces height and spots a man down below. He lowers the balloon further and shouts to get directions, "Excuse me, can you tell me where I am?"

The man below says: "Yes. You're in a hot air balloon, hovering 30 feet above this field."

"You must work in Information Technology," says the balloonist.

"I do" replies the man. "How did you know?"

"Well," says the balloonist, "everything you have told me is technically correct, but It's of no use to anyone."

The man below replies, "You must work in management."

"I do," replies the balloonist, "But how'd you know?"

"Well", says the man, "you don’t know where you are, or where you’re going, you expect me to be able to help. You’re in the same position you were before we met, but now it’s my fault."

Twitter like alert after form submit in jquery...

2010-06-22T15:39:00.001+05:30

Just got my example to work and here it is,

function topBar(message) {
   var $alert = $('<div/>');
   $alert.text(message);
   $alert.click(function() {
   $(this).slideUp(200);
   });
   $(body).append($alert);
   setTimeout(function() { $alert.slideUp(200) }, 5000);
}

and css:

#alert
{
overflow: hidden;
width: 100%;
text-align: center;
position: absolute;
top: 0;
left: 0;
background-color: #FF0000;
height: 0;
color: #FFFFFF;
font: 20px/40px arial, sans-serif;
opacity: .9;
}

Try it and let me know for doubts...

Fluent NHibernate configuration (Ms Sql Server 2005 & Mysql)..

2010-06-21T11:56:00.000+05:30

NHibernate is popular in Open-source community, fully featured, mature ORM but the way to config mappings in XML files (.hbm.xml files) is not comfort.

I would prefer to write mappings in strongly typed C# code and enjoy from easy refactoring, improved readability and more concise code.

Fluent NHibernate resolves this issue and provides alternative to NHibernate's standard XML mapping files - fluent, XML-less, compile safe.

Samples of mappings:

public class CustomerMap : ClassMap<Customer>
{
public CustomerMap()
{
WithTable("Customers");

Id(x => x.Id, "CustomerId");
Map(x => x.Firstname);
Map(x => x.Lastname);
Map(x => x.Email, "EmailAddress");
}
}

//For sql server2005
Fluently.Configure()
.Database(MsSqlConfiguration.MsSql2005
.ConnectionString(c => c
.FromAppSetting("connectionString"))
.Cache(c => c
.UseQueryCache()
.ProviderClass<HashtableCacheProvider>())
.ShowSql())
.Mappings(m => m
.FluentMappings.AddFromAssemblyOf<Customer>())
.BuildSessionFactory();
//For Mysql
Fluently.Configure()
.Database(MySqlConfiguration.Standard
.ConnectionString(c => c.FromConnectionStringWithKey("ConnectionString"))) .Mappings(m => m.FluentMappings.AddFromAssemblyOf()) .BuildSessionFactory())

Always looking forward to maintain whole schema of a database is really challenging..

Getting started with GPS and IVR integration with asp.net mvc...

2010-06-21T11:29:00.000+05:30

I was going through some articles about IVR(Interactive voice response) and GPS(Global positioning system)... I just loved the concept and started to find API's for each... Looking forward to face the challenge...

When to choose ORM as data access instead of ADO.NET?

2010-06-17T17:15:00.000+05:30

I mentioned that I think that hand rolled data access layers using stored procedures are a bad thing, and one of my co-workers asked me to elaborate.

The main reason that I don’t like hand rolled data access layers is that by writing your own DAL, you are basically reimplementing a solved problem. Think about all of the things you have worry about if you write your own DAL:

Creating the CRUD stored procs
Writing ADO.NET code to call the stored procs
Figuring out which entities are dirty and need to be saved, and which properties have changed
What relationships do you load when you load an entity from the database? How do you do lazy loading of relationships?
Writing tests to test all of this custom code that you have to write

There are numerous object-relational mapping (ORM) tools out there which take care of all of this. NHibernate is my favorite (more specifically, Fluent NHibernate). NHibernate has been around for several years and is very mature. There are ORMs from Microsoft (LINQ to SQL, Entity Framework), and numerous other ORMs out there.

These ORMs have thousands of people using them, so they have been well tested and have proven over time to be very effective at what they do. Countless hours have gone into the development, design, and testing of these ORMs.

Think about what you are trying to do by writing your own hand rolled data access layer. Who are you to think that you can do a better job in a short amount of time than the people who developed these mature solutions over several years? Data access is a very complicated thing to try and implement, and some of the most painful code that I’ve ever had to deal with was found in someone’s hand rolled data access layer.

Here’s the thing — a large percentage of your data access is vanilla loading and saving of objects from the database. In these cases, performance is not a concern and you do not need any special queries in order to optimize the loading and saving of these objects.

For a very small percentage of your data access, performance may be a concern and you may need to use custom stored procedures. So in these cases, you can bypass the ORM and write your stored procedures and custom code in order to optimize the loading and saving of these specific objects.

If you use stored procedures and custom code, you have more control over things. This also comes with a cost (longer time to develop). If you are accepting this cost for cases where you don’t need to optimize the data access, I would say that you’ve wasted time on premature optimization, not to mention that you’ve probably had to spend time implementing all of that data access code.

I would rather use an ORM that has implemented everything that is difficult about data access. Now all I have to tell it how to map to the database (which isn’t that hard) and tell it to do things for me. With lazy loading, it won’t load entity relationships (e.g. child collections on an entity object) unless it needs to. It knows when objects are dirty and if they need to be saved or not. I have an easy hook so that I can validate entities when they are saved.

The other day I configured a cache in NHibernate in 15 minutes. With very little code I was able to set NHibernate up so that it will cache entities that don’t ever change in memory so that it doesn’t have to get to the database to get them every time. There were numerous examples on the internet telling me how to do this, and I’m extremely confident that it’s going to work (I didn’t have to write any of the difficult code for caching because NHibernate has solved that problem).

I want to write code that solves business problems. Thankfully other people have written libraries that will help me do that. So I’m going to use them.

Fluent nHibernate rocks with asp.net MVC...

2010-06-10T11:24:00.001+05:30

Just got my asp.net mvc web application to work with fluent Nhibernate... Just loved the way it ships with asp.net MVC... Looking forward to the challenges when deploying it to live server......

"Remember the Milk" really rocks my work schedule...

2010-06-05T14:19:00.000+05:30

Remember the milk really rocks my work schedule.... I got started with it a week ago and its looks really cool... Guys give a try....

Just learnt to set folder permissions in iis...

2010-05-24T11:10:00.002+05:30

IIS Folder permission:

Tool->Options->View->Use simple file sharing(recommended)--- Uncheck it.....

RightClick on the folder to give permissions,

Security->Asp.net account -> Full control -> check all

Its Time to move from asp.net webforms to asp.net mvc...

2010-05-05T12:00:00.001+05:30

To all my .net friends,
I was working with asp.net mvc and ships really well with jquery..... Just give a try with asp.net mvc......

Biggest advantage to using ASP.Net MVC over web forms

The main advantages of ASP.net MVC are

1) Enables the full control over the rendered HTML.

2) Provides clean separation of concerns(SoC).

3) Enables Test Driven Development (TDD).

4) Easy integration with JavaScript frameworks.

5) Following the design of stateless nature of the web.

6) RESTful urls that enables SEO.

7) No ViewState and PostBack events

The main advantage of ASP.net Web Form are

1) It provides RAD development

2) Easy development model for developers those coming from winform development.

Jquery replaces Flash... Really cool....

2010-04-06T17:19:00.000+05:30

Just try this,

<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
   <title></title>
   <script type="text/javascript" src="jquery.js"></script>
   <link rel="Stylesheet" type="text/css" href="CSS/Main.css" />
   <style type="text/css>
   #BannerDiv {width: 954px; height: 327px;}
   #BannerDiv img {position: absolute; width: 954px; height: 327px; display: none;}
   </style>
</head>
<body>
   <form id="form1" runat="server">
   <div>
   <div Id="BannerDiv">
   <img src="Images/banner3.jpg" alt="image1"/>
   <img src="Images/ban_main_25.jpg" alt="image2"/>
   <img src="Images/banner_25.jpg" alt="image3"/>
   </div>
   </div>
   <script type="text/javascript">
   $(function() {
   $('#BannerDiv > :first').show();
   setTimeout(rotate,1000);
   });

   function rotate() {
   var c = $('#BannerDiv > :visible').css({ 'z-index': 2 }).fadeOut(2000, function() {
   setTimeout(rotate, 1000);
   }).next().css({ 'z-index': 1 }).show();
   if (c.length == 0) $('#BannerDiv > :first').css({ 'z-index': 1 }).show();
   }
   </script>
   </form>
</body>
</html>

Include your images to see the demo...

Jquery + Asp.net page methods really cool you got to love it...

2010-03-30T12:19:00.006+05:30

In your aspx page....

<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
   <title></title>
   <link rel="Stylesheet" type="text/css" href="CSS/Main.css" />
   <script type="text/javascript" src="jquery.js"></script>
   <script type="text/javascript" src="Javascript/Data.js"></script>

</head>
<body>
<form id="form1" runat="server">
   <div id="PagerUp" class="pager">

</div><br /><br /><br />
   <div id="ResultsDiv">

</div>
<div id="PagerDown" class="pager">

</div>
   <input id="HfId" type="hidden" />
   <script type="text/javascript">
   var itemsPerPage = 5;
   $(document).ready(function() {
   getRecordspage(0, itemsPerPage);
   $(".pager").pagination($("#HfId").val(), {
   callback: getRecordspage,
   current_page: 0,
   items_per_page: itemsPerPage,
   num_display_entries: 5,
   next_text: 'Next',
   prev_text: 'Prev',
   num_edge_entries: 1
   });
   });
   </form>
</script>
</body>
</html>

In yourcodebehind aspx.cs;

using System;
using System.Collections.Generic;
using System.Linq;
using System.Data;
using System.Data.Sql;
using System.Data.SqlClient;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.Services;
using Microsoft.ApplicationBlocks.Data;
using System.Text;

public partial class _Default : System.Web.UI.Page
{
   protected void Page_Load(object sender, EventArgs e)
   {

   }
   [WebMethod]
   public static string GetRecords(int currentPage,int pagesize)
   {
   string connectionString = System.Configuration.ConfigurationManager.ConnectionStrings["connectionString"].ConnectionString;
   SqlParameter[] _spParams = new SqlParameter[2];
   _spParams[0] = new SqlParameter("@CurrentPage", currentPage);
   _spParams[1] = new SqlParameter("@PageSize", pagesize);
   DataSet ds = SqlHelper.ExecuteDataset(connectionString, CommandType.StoredProcedure, "Employee_View_Paging", _spParams);


StringBuilder headStrBuilder = new StringBuilder(ds.Tables[0].Columns.Count * 5); //pre-allocate some space, default is 16 bytes
   for (int i = 0; i < ds.Tables[0].Columns.Count; i++)
   {
   headStrBuilder.AppendFormat("\"{0}\" : \"{0}{1}¾\",", ds.Tables[0].Columns[i].Caption, i);
   }
   headStrBuilder.Remove(headStrBuilder.Length - 1, 1); // trim away last ,

   StringBuilder sb = new StringBuilder(ds.Tables[0].Rows.Count * 5); //pre-allocate some space
   sb.Append("{\"");
   sb.Append(ds.Tables[0].TableName);
   sb.Append("\" : [");
   for (int i = 0; i < ds.Tables[0].Rows.Count; i++)
   {
   string tempStr = headStrBuilder.ToString();
   sb.Append("{");
   for (int j = 0; j < ds.Tables[0].Columns.Count; j++)
   {
   ds.Tables[0].Rows[i][j] = ds.Tables[0].Rows[i][j].ToString().Replace("'", "");
   tempStr = tempStr.Replace(ds.Tables[0].Columns[j] + j.ToString() + "¾", ds.Tables[0].Rows[i][j].ToString());
   }
   sb.Append(tempStr + "},");
   }
   sb.Remove(sb.Length - 1, 1); // trim last ,
   sb.Append("]}");

     return sb.Append("##").Append(ds.Tables[1].Rows[0].ItemArray[0]).Append("##").Append(ds.Tables[2].Rows[0].ItemArray[0]).ToString();
   }



}

In your js....

function getRecordspage(curPage) {
   $.ajax({
   type: "POST",
   url: "Default.aspx/GetRecords",
   data: "{'currentPage':" + (curPage + 1) + ",'pagesize':5}",
   contentType: "application/json; charset=utf-8",
   async: false,
   dataType: "json",
   success: function(jsonObj) {
   $("#ResultsDiv").empty();
   $("#HfId").val("");
   var strarr = jsonObj.d.split('##');
   var jsob = jQuery.parseJSON(strarr[0]);
   var divs = '';
   $.each(jsob.Table, function(i, employee) {
   divs += '<div class="resultsdiv"><br /><span class="resultName">' + employee.Emp_Name + '</span><span class="resultfields" style="padding-left:100px;">Category :</span> <span class="resultfieldvalues">' + employee.Desig_Name + '</span><br /><br /><span id="SalaryBasis" class="resultfields">Salary Basis :</span> <span class="resultfieldvalues">' + employee.SalaryBasis + '</span><span class="resultfields" style="padding-left:25px;">Salary :</span> <span class="resultfieldvalues">' + employee.FixedSalary + '</span><span style="font-size:110%;font-weight:bolder;padding-left:25px;">Address :</span> <span class="resultfieldvalues">' + employee.Address + '</span></div>';
   });
   $("#ResultsDiv").append(divs);
   $(".resultsdiv:even").addClass("resultseven");
   $(".resultsdiv").hover(function() {
   $(this).addClass("resultshover");
   }, function() {
   $(this).removeClass("resultshover");
   });
   $("#HfId").val(strarr[1]);


var paginationClone = $("#PagerUp > *").clone(true);
   $("#PagerDown").empty();
   paginationClone.appendTo("#PagerDown");
   }
   });
}

Css:

.resultsdiv
{
background-color: #FFF;border-top:solid 1px #ddd; height:50px; border-bottom:solid 1px #ddd; padding-bottom:15px; width:450px;
}
.resultseven { background-color: #EFF1f1; }
.resultshover { background-color: #F4F2F2; cursor:pointer; }

.resultName
{
font-size:125%;font-weight:bolder;color:#476275;font-family:Arial,Liberation Sans,DejaVu Sans,sans-serif;
}
.resultfields
{
font-size:110%;font-weight:bolder;font-family:Arial,Liberation Sans,DejaVu Sans,sans-serif;
}
.resultfieldvalues
{
color:#476275;font-size:110%;font-weight:bold;font-family:Arial,Liberation Sans,DejaVu Sans,sans-serif;
}

Stored Procedure:

ALTER PROCEDURE [dbo].[Employee_View_Paging]
@CurrentPage INT,
@PageSize INT
AS
BEGIN
-- SET NOCOUNT ON added to prevent extra result sets from
-- interfering with SELECT statements.
SET NOCOUNT ON;

   -- Insert statements for procedure here
-- SELECT e.Emp_Id,e.Identity_No,e.Emp_Name,e.Address,convert(varchar, e.Date_Of_Birth, 103) as Date_Of_Birth,d.Desig_Name,d.Desig_Description,case WHEN e.SalaryBasis=1 THEN 'Weekly' ELSE 'Monthly' end as SalaryBasis,e.FixedSalary
-- from Employee as e inner join Designation as d on e.Desig_Id=d.Desig_Id where e.Is_Deleted=0

   SELECT ROW_NUMBER() OVER (ORDER BY Emp_Id) AS Row,Emp_Id,Emp_Name,[Address],Desig_Name,SalaryBasis,FixedSalary FROM
   (
   SELECT
   ROW_NUMBER() OVER (ORDER BY Emp_Id) AS Row,Emp_Id,Emp_Name,[Address],Desig_Name,SalaryBasis,FixedSalary
   FROM Employee_View
   ) AS EmpWitRowNos
   WHERE Row >= (@CurrentPage - 1) * @PageSize + 1 AND Row <= @CurrentPage*@PageSize

   SELECT COUNT(*) as TotalCount FROM Employee_View

   SELECT CEILING(COUNT(*) / CAST(@PageSize AS FLOAT)) NumberOfPages
   FROM Employee_View
END

ViewState Compression ....

2010-03-25T11:15:00.000+05:30

Compressing and Decompressing Data in Memory

The code below is really simple, and doesn't need further explanation:

using System.IO;

using System.IO.Compression;

public static class Compressor

{

public static byte[] Compress(byte[] data)

{

MemoryStream output = new MemoryStream();

GZipStream gzip = new GZipStream(output,

CompressionMode.Compress, true);

gzip.Write(data, 0, data.Length);

gzip.Close();

return output.ToArray();

}

public static byte[] Decompress(byte[] data)

{

MemoryStream input = new MemoryStream();

input.Write(data, 0, data.Length);

input.Position = 0;

GZipStream gzip = new GZipStream(input,

CompressionMode.Decompress, true);

MemoryStream output = new MemoryStream();

byte[] buff = new byte[64];

int read = -1;

read = gzip.Read(buff, 0, buff.Length);

while (read > 0)

{

output.Write(buff, 0, read);

read = gzip.Read(buff, 0, buff.Length);

}

gzip.Close();

return output.ToArray();

}

In your base page include these methods and you are done:

protected override object LoadPageStateFromPersistenceMedium()

{

string viewState = Request.Form["__VSTATE"];

byte[] bytes = Convert.FromBase64String(viewState);

bytes = Compressor.Decompress(bytes);

LosFormatter formatter = new LosFormatter();

return formatter.Deserialize(Convert.ToBase64String(bytes));

}

protected override void SavePageStateToPersistenceMedium(object viewState)

{

LosFormatter formatter = new LosFormatter();

StringWriter writer = new StringWriter();

formatter.Serialize(writer, viewState);

string viewStateString = writer.ToString();

byte[] bytes = Convert.FromBase64String(viewStateString);

bytes = Compressor.Compress(bytes);

ClientScript.RegisterHiddenField("__VSTATE", Convert.ToBase64String(bytes));

}

Now view your aspx page in firefox Viewstate size addon will show your reduced size...

Add divs below a parent div using jquery...

2010-03-23T13:13:00.000+05:30

The following function will allow you to add div below a parent div

function Iteratejsondata(HfJsonValue) {
   var jsonObj = eval('(' + HfJsonValue + ')');

   for (var i = 0, len = jsonObj.Table.length; i < len; ++i) {
   var employee = jsonObj.Table[i];
   $('<div class="resultsdiv"><br /><span id="EmployeeName" style="font-size:125%;font-weight:bolder;">' + employee.Emp_Name + '</span><span style="font-size:100%;font-weight:bolder;padding-left:100px;">Category :</span> <span>' + employee.Desig_Name + '</span><br /><br /><span id="SalaryBasis" style="font-size:100%;font-weight:bolder;">Salary Basis :</span> <span>' + employee.SalaryBasis + '</span><span style="font-size:100%;font-weight:bolder;padding-left:25px;">Salary :</span> <span>' + employee.FixedSalary + '</span><span style="font-size:100%;font-weight:bolder;padding-left:25px;">Address :</span> <span>' + employee.Address + '</span></div>').insertAfter('#ResultsDiv');
   //document.write(employee.Emp_Name);
   }
}

FInd 3rd MAX salary in Sql Server?

2010-03-19T10:50:00.002+05:30

Use the following...

DECLARE @Table TABLE(
   Wages FLOAT
)

INSERT INTO @Table SELECT 20000
INSERT INTO @Table SELECT 15000
INSERT INTO @Table SELECT 10000
INSERT INTO @Table SELECT 45000
INSERT INTO @Table SELECT 50000

--SELECT MAX(Wages)
--FROM @Table where Wages < (select MAX(Wages) from @Table where wages < (select MAX(Wages) from @Table))

SELECT *
FROM (
   SELECT *,
   ROW_NUMBER() OVER(ORDER BY Wages DESC) RowID
   FROM @Table
   ) sub
WHERE RowID = 3

Advantages of jQuery

2010-03-17T17:43:00.003+05:30

Advantages of jQuery

1. It’s lightweight, easy and fast.

2. Write less but do more.

3. Cross Browser Compatibility.

4. Separate javascript code from HTML mark-up.

5. Easy and Light-weight Ajax Application.

6. Availability of various plug-in’s.

7. You can extend it.

8. We can use CDN (Content Distribution Network) for internet site.

9. Microsoft and Intellisense support in Visual Studio 2008.

10. Easy Integration with ASP.Net Ajax projects.

Moving forward, we will look deeply into the above advantages with examples.

1. It’s lightweight, easy and fast

jQuery library as such is not a bulky library in terms of size(just 20KB in compressed form), execution time, etc. Once you start using jQuery, you can understand its simplicity and it will take very less development time when compared to classical javascript code. As I said earlier, just including the jQuery library using <script> tag is all you need to work on jQuery. It has no security risk associated with it. You can include it in your project just like any other javascript file.

2. Write less but do more

The main advantage of jQuery library is, we can do various complex client side operations with very less code. This is because of various selector expressions support, chaining mechanism and other similar features of jQuery which makes the complex DOM manipulation lot easier.

To select a HTML element in javascript,

document.getElementById('txtName');

The above equivalent in jQuery will be,

$('#txtName');

To select all the rows in a table and setting a background color,

<script src="_scripts/jquery-1.3.2.min.js" type="text/javascript"></script>

    <script language="javascript">

        $(document).ready(function() {

            $('#table1 > tbody > tr').css("background-color", "Red");          

});

  </script>

Refer jQuery selector documentation to know more on jQuery selectors.

Refer the below 2 articles which will check the CheckBoxes in all the rows when we select the header CheckBox in a GridView control to understand the above point. First uses javascript and former uses jQuery library.

GridView with CheckBox – Select All and Highlight Selected Row – JavaScript Version and more code.

Check All Checkboxes in GridView using jQuery – jQuery version and less code.

The other advantage of jQuery is using the chaining mechanism which will help us to reduce the code.

Refer the below code to understand better,

<script language="javascript">

        $(document).ready(function() {          

            $('#txtName').css("background-color", "Red").val("Test");

});

    </script>

The above code selects a TextBox control with ID txtName, then applies css style and then set its text as “Test”.

3. Cross Browser Compatibility

The jQuery code we write is compatible with all the browsers and hence it prevents the need to write separate client side code for different browsers. Remember to set the css properties that are cross-browser compatible when using jQuery for cross browser compatibility.

4. Separate javascript code from HTML mark-up

jQuery library enables us to separate the client side scripts from the HTML mark-ups. This is possible because of $(document).ready() function of jQuery.

For example,

<input id="btnSubmit" onclick="javscript:Save()" type="button" value="button" />

The above code can written as,

    <script src="_scripts/jquery-1.3.2.min.js" type="text/javascript"></script>

    <script language="javascript">

        $(document).ready(function() {         

            $('#btnSubmit').click(function() {

                alert('Submit Clicked!');

});

});

    </script>

Thus, when we use jQuery library we can make our HTML code neat without any javascript code combined with it.

It is also possible to separate jQuery code into a separate javascript file and link to the aspx page. For example, the above code can be separated in a separate javascript file and it can be linked to the aspx page. Refer the below code,

ASPX

<head runat="server">

    <title></title>

    <script src="_scripts/jquery-1.3.2.min.js" type="text/javascript"></script>

     <script src="_scripts/Default.js" type="text/javascript"></script>

    </script>

</head>

Default.js

$(document).ready(function() {  

    $('#btnSubmit').click(function() {

        alert('Submit Clicked!');

});

});

5. Easy and Light-weight Ajax Application

One of biggest advantages of using jQuery library is developing light weight Ajax application in ASP.Net with JSON support. With jQuery library we can prevent the bulky ASP.Net AJAX’s UpdatePanel control for Ajax communications.

Refer my articles on codedigest.com to know more,

1. Building Cascading DropDownList in ASP.Net Using jQuery and JSON

2. Creating a Simple AJAX Master-Details View Using jQuery, JSON and jTemplates in ASP.Net

3. Building Collapsible Panel Control using jQuery in ASP.Net Page

4. Populating RadioButtonList Using jQuery, JSON in ASP.Net

5. GridView Style Edit Update in Repeater Control Using jQuery and Ajax

6. Using JQuery in ASP.Net AJAX Applications – Part 1

7. Using JQuery in ASP.Net AJAX Applications–Part 2

6. Availability of various plug-in’s

There are various free plug-in’s available on the internet which we can use in our projects. For example, jQuery tabs, jTemplate, etc.

Refer the plug-in’s directory here. Since, the jQuery usage is becoming high day by day there are already lots of plug-in’s available online which we can re-use.

7. You can extend it

It is also possible to extend existing functionality provided by jQuery library.

Refer the below post which talks about jQuery Custom Selectors.

8. We can use CDN (Content Distribution Network) for internet site

If our site is hosted on internet, then we can start using the jQuery library hosted by Google CDN, Content Distribution Network.

Google's Content Distribution Network (also, AJAX Libraries API) hosts most widely used open source JavaScript libraries which can be used globally across the websites. The main advantage of using google's CDN is they manage all the bug fixes, recent updates and provide a high speed access due to better caching, etc.

Read Using the JQuery Library hosted by Google CDN (Content Distribution Network) in ASP.Net Applications to know more.

9. Microsoft and Intellisense support in Visual Studio 2008

Refer the below 2 FAQ’s to know more,

How to enable jQuery intellisense in Visual Studio 2008?

How to use jQuery intellisense in an external javascript file?

10. Easy Integration with ASP.Net Ajax projects

jQuery library can be easily integrated with ASP.Net Ajax applications. Remember the ready event will not fire for an asynchronous postback caused from UpdatePanel control. The ASP.Net AJAX equivalent of ready() function is endRequest event.

<script type="text/JavaScript" language="JavaScript">

    function pageLoad()

{

       var manager = Sys.WebForms.PageRequestManager.getInstance();

       manager.add_endRequest(endRequest);

}

    function endRequest(sender, args)

{

      //Do all what you want to do in jQuery ready function

}

</script>

Be proud to be a Developer

2010-03-03T18:02:00.003+05:30

C# Interview Questions

2010-03-02T10:11:00.000+05:30

General Questions

Does C# support multiple-inheritance?
No.
Who is a protected class-level variable available to? It is available to any sub-class (a class inheriting this class).
Are private class-level variables inherited? Yes, but they are not accessible. Although they are not visible or accessible via the class interface, they are inherited.
Describe the accessibility modifier “protected internal”. It is available to classes that are within the same assembly and derived from the specified base class.
What’s the top .NET class that everything is derived from?
System.Object.
What does the term immutable mean?
The data value may not be changed. Note: The variable value may be changed, but the original immutable data value was discarded and a new data value was created in memory.
What’s the difference between System.String and System.Text.StringBuilder classes?
System.String is immutable. System.StringBuilder was designed with the purpose of having a mutable string where a variety of operations can be performed.
What’s the advantage of using System.Text.StringBuilder over System.String?
StringBuilder is more efficient in cases where there is a large amount of string manipulation. Strings are immutable, so each time a string is changed, a new instance in memory is created.
Can you store multiple data types in System.Array?
No.
What’s the difference between the System.Array.CopyTo() and System.Array.Clone()?The Clone() method returns a new array (a shallow copy) object containing all the elements in the original array. The CopyTo() method copies the elements into another existing array. Both perform a shallow copy. A shallow copy means the contents (each array element) contains references to the same object as the elements in the original array. A deep copy (which neither of these methods performs) would create a new instance of each element's object, resulting in a different, yet identacle object.
How can you sort the elements of the array in descending order?By calling Sort() and then Reverse() methods.
What’s the .NET collection class that allows an element to be accessed using a unique key?HashTable.
What class is underneath the SortedList class?A sorted HashTable.
Will the finally block get executed if an exception has not occurred?Yes.
What’s the C# syntax to catch any possible exception?A catch block that catches the exception of type System.Exception. You can also omit the parameter data type in this case and just write catch {}.
Can multiple catch blocks be executed for a single try statement?No. Once the proper catch block processed, control is transferred to the finally block (if there are any).
Explain the three services model commonly know as a three-tier application.Presentation (UI), Business (logic and underlying code) and Data (from storage or other sources).

Class Questions

What is the syntax to inherit from a class in C#? Place a colon and then the name of the base class.
Example: class MyNewClass : MyBaseClass
Can you prevent your class from being inherited by another class? Yes. The keyword “sealed” will prevent the class from being inherited.
Can you allow a class to be inherited, but prevent the method from being over-ridden?Yes. Just leave the class public and make the method sealed.
What’s an abstract class?A class that cannot be instantiated. An abstract class is a class that must be inherited and have the methods overridden. An abstract class is essentially a blueprint for a class without any implementation.
When do you absolutely have to declare a class as abstract?
1. When the class itself is inherited from an abstract class, but not all base abstract methods have been overridden.
2. When at least one of the methods in the class is abstract.
What is an interface class?Interfaces, like classes, define a set of properties, methods, and events. But unlike classes, interfaces do not provide implementation. They are implemented by classes, and defined as separate entities from classes.
Why can’t you specify the accessibility modifier for methods inside the interface?They all must be public, and are therefore public by default.
Can you inherit multiple interfaces?Yes. .NET does support multiple interfaces.
What happens if you inherit multiple interfaces and they have conflicting method names?It’s up to you to implement the method inside your own class, so implementation is left entirely up to you. This might cause a problem on a higher-level scale if similarly named methods from different interfaces expect different data, but as far as compiler cares you’re okay.
To Do: Investigate
What’s the difference between an interface and abstract class?In an interface class, all methods are abstract - there is no implementation. In an abstract class some methods can be concrete. In an interface class, no accessibility modifiers are allowed. An abstract class may have accessibility modifiers.
What is the difference between a Struct and a Class?
Structs are value-type variables and are thus saved on the stack, additional overhead but faster retrieval. Another difference is that structs cannot inherit.

Method and Property Questions

What’s the implicit name of the parameter that gets passed into the set method/property of a class? Value. The data type of the value parameter is defined by whatever data type the property is declared as.
What does the keyword “virtual” declare for a method or property? The method or property can be overridden.
How is method overriding different from method overloading? When overriding a method, you change the behavior of the method for the derived class. Overloading a method simply involves having another method with the same name within the class.
Can you declare an override method to be static if the original method is not static? No. The signature of the virtual method must remain the same. (Note: Only the keyword virtual is changed to keyword override)
What are the different ways a method can be overloaded? Different parameter data types, different number of parameters, different order of parameters.
If a base class has a number of overloaded constructors, and an inheriting class has a number of overloaded constructors; can you enforce a call from an inherited constructor to a specific base constructor?Yes, just place a colon, and then keyword base (parameter list to invoke the appropriate constructor) in the overloaded constructor definition inside the inherited class.

Events and Delegates

What’s a delegate? A delegate object encapsulates a reference to a method.
What’s a multicast delegate? A delegate that has multiple handlers assigned to it. Each assigned handler (method) is called.

XML Documentation Questions

Is XML case-sensitive? Yes.
What’s the difference between // comments, /* */ comments and /// comments? Single-line comments, multi-line comments, and XML documentation comments.
How do you generate documentation from the C# file commented properly with a command-line compiler? Compile it with the /doc switch.

Debugging and Testing Questions

What debugging tools come with the .NET SDK?1. CorDBG – command-line debugger. To use CorDbg, you must compile the original C# file using the /debug switch.2. DbgCLR – graphic debugger. Visual Studio .NET uses the DbgCLR.
What does assert() method do? In debug compilation, assert takes in a Boolean condition as a parameter, and shows the error dialog if the condition is false. The program proceeds without any interruption if the condition is true.
What’s the difference between the Debug class and Trace class? Documentation looks the same. Use Debug class for debug builds, use Trace class for both debug and release builds.
Why are there five tracing levels in System.Diagnostics.TraceSwitcher? The tracing dumps can be quite verbose. For applications that are constantly running you run the risk of overloading the machine and the hard drive. Five levels range from None to Verbose, allowing you to fine-tune the tracing activities.
Where is the output of TextWriterTraceListener redirected?
To the Console or a text file depending on the parameter passed to the constructor.
How do you debug an ASP.NET Web application?
Attach the aspnet_wp.exe process to the DbgClr debugger.
What are three test cases you should go through in unit testing? 1. Positive test cases (correct data, correct output).2. Negative test cases (broken or missing data, proper handling).3. Exception test cases (exceptions are thrown and caught properly).
Can you change the value of a variable while debugging a C# application? Yes. If you are debugging via Visual Studio.NET, just go to Immediate window.

ADO.NET and Database Questions

What is the role of the DataReader class in ADO.NET connections? It returns a read-only, forward-only rowset from the data source. A DataReader provides fast access when a forward-only sequential read is needed.

What are advantages and disadvantages of Microsoft-provided data provider classes in ADO.NET? SQLServer.NET data provider is high-speed and robust, but requires SQL Server license purchased from Microsoft. OLE-DB.NET is universal for accessing other sources, like Oracle, DB2, Microsoft Access and Informix. OLE-DB.NET is a .NET layer on top of the OLE layer, so it’s not as fastest and efficient as SqlServer.NET.

What is the wildcard character in SQL? Let’s say you want to query database with LIKE for all employees whose name starts with La. The wildcard character is %, the proper query with LIKE would involve ‘La%’.

Explain ACID rule of thumb for transactions.A transaction must be:1. Atomic - it is one unit of work and does not dependent on previous and following transactions.2. Consistent - data is either committed or roll back, no “in-between” case where something has been updated and something hasn’t.3. Isolated - no transaction sees the intermediate results of the current transaction).4. Durable - the values persist if the data had been committed even if the system crashes right after.

What connections does Microsoft SQL Server support? Windows Authentication (via Active Directory) and SQL Server authentication (via Microsoft SQL Server username and password).

Between Windows Authentication and SQL Server Authentication, which one is trusted and which one is untrusted?
Windows Authentication is trusted because the username and password are checked with the Active Directory, the SQL Server authentication is untrusted, since SQL Server is the only verifier participating in the transaction.

What does the Initial Catalog parameter define in the connection string?
The database name to connect to.

What does the Dispose method do with the connection object? Deletes it from the memory.To Do: answer better. The current answer is not entirely correct.

What is a pre-requisite for connection pooling?
Multiple processes must agree that they will share the same connection, where every parameter is the same, including the security settings. The connection string must be identical.

Assembly Questions

How is the DLL Hell problem solved in .NET? Assembly versioning allows the application to specify not only the library it needs to run (which was available under Win32), but also the version of the assembly.
What are the ways to deploy an assembly? An MSI installer, a CAB archive, and XCOPY command.
What is a satellite assembly?
When you write a multilingual or multi-cultural application in .NET, and want to distribute the core application separately from the localized modules, the localized assemblies that modify the core application are called satellite assemblies.
What namespaces are necessary to create a localized application? System.Globalization and System.Resources.
What is the smallest unit of execution in .NET?
an Assembly.
When should you call the garbage collector in .NET?
As a good rule, you should not call the garbage collector. However, you could call the garbage collector when you are done using a large object (or set of objects) to force the garbage collector to dispose of those very large objects from memory. However, this is usually not a good practice.
How do you convert a value-type to a reference-type?
Use Boxing.
What happens in memory when you Box and Unbox a value-type?
Boxing converts a value-type to a reference-type, thus storing the object on the heap. Unboxing converts a reference-type to a value-type, thus storing the value on the stack.

Why C# is used more or preferred over VB.NET?

2010-03-02T09:45:00.004+05:30

I believe the answer to this question has mostly to do with syntax and history.

Although VB.NET is an excellent language, the problem with VB.NET has more to do with the history of BASIC than what VB.NET is today. I can tell you that I prefer C# over VB.NET, and I programmed with Visual Basic versions 3 through 6 with much success. However, as any ex-Visual Basic developer an attest to, Visual Basic was always viewed as a second-rate language by C++ and Java developers. There were certainly a number of things that the C++ language would allow over Visual Basic, and not all of them were necessarily positive. Much of the flexibility allowed by C++ was also the demise of many C++ applications.

I viewed C++ like a surgeon’s scalpel. With a scalpel, it can take a long time to carve out a piece of art. And, in the wrong hands you can do more damage than good, as I have seen. However, in the right hands, you can do very good things. With C++ a developer could do virtually anything since C++ was the core language on which most operating systems were written, and the core for the Microsoft libraries.

Visual Basic was intended to address the need to rapidly develop applications for the largest share of applications needed, such as business applications. Business applications are more about good business process logic and intuitive user interfaces, not complex user interfaces or algorithms. Visual Basic was Microsoft's initial attempt at providing a development language to improve programmer productivity. Visual Basic addressed this need well.

With this little bit of history, programmers who used Visual Basic were not considered by some (C++ and Java developers) to be “professional” developers. The fact that Visual Basic had the word “Basic” in it was probably the single most dominating reason – in my opinion. Anything that is “Basic” is probably not powerful – as viewed by many who never really ever used Visual Basic. I must confess, I had the same biases about other database-related languages like FoxPro and DBase – and I was probably overly critical about those and other tools as well.

I personally have a great deal of respect for Visual Basic and its place in history. For me, it was the right tool for many solutions at that time. Visual Basic versions 3 through 6 existed during a time when companies were only beginning to see the advantages of Local Area Networks (LAN), the wide-spread introduction of the Internet and the explosion of the Internet, all of which happened during the timeline of Visual Basic.

If I may deviate a bit, during this time most companies; except for the large Fortune 1000 type companies), viewed personal computers and LAN’s as an expensive investment with very little return on investment (ROI). This close scrutiny of Information Technology investments eventually proved to be a good investment in productivity for the average company. The investment in technology then began to swing the other direction at a pace where many companies and investors could not throw enough money into the advancement of technology and new technology companies; and as we all know, this ended with the DOT-COM boom and bust.

Back to the original question about VB.NET or C#. The important thing to remember is that both VB.NET and C# get their muscle from the .NET Framework. Other than a few minor differences in functionality between the two, the decision becomes mostly driven by syntax. I do not include functional because all .NET languages are interoperable with one another. Again this is provided by the .NET Framework. I personally prefer the C# syntax. It is more like C++, JavaScript, and Java. Although I don’t use Java, I like developing in a syntax that is more widely adopted. I use JavaScript occasionally and as a creature of habit I like that C# and JavaScript are similar in basic syntax. I also prefer the terminology or keywords used by C# because they are more object oriented in nature.

This is my preference from a non-technical approach. Your comments are welcome.

Flying with WCF and Jquery in asp.net

2010-02-12T10:06:00.005+05:30

Hai guys,
Just started to use WCF and Jquery with one of my application it looks really awesome.... No postbacks,No server controls,No events only ajax stuff..... Soon the site will be up and running .....

Some of the useful links for WCF undefined errors,

http://weblogs.asp.net/scottgu/archive/2007/04/11/public-hotfix-patch-available-for-asp-net-compilation-issues.aspx

http://www.west-wind.com/weblog/posts/306990.aspx

http://www.hanselman.com/blog/PermaLink,guid,d88f7539-10d8-4697-8c6e-1badb08bb3f5.aspx

http://blogs.msdn.com/isha/archive/2009/04/04/issues-with-wcf-service-when-the-asp-net-website-is-deployed-using-the-web-deployment-project-and-as-non-updatable-project.aspx

In aspx page:

function GetDesignation() {
Service.GetDesignationData(onGetDataSuccess);
}
function onGetDataSuccess(result) {
DesignationDatatable(result);
addclick();
}
function InsertDesignation() {
Service.SetDesignationInsertData($("#TxtDesigName").val(), $("#TxtDescription").val());
Service.GetDesignationData(OnInsertSuccess);
}
function OnInsertSuccess(result) {

Service.GetDesignationData(onGetDataSuccess);

}

$(document).ready(function() {
GetDesignation();
HideDiv();
});

function addclick() {
$("#submitt").click(function(event) {
$("#datatable").fadeIn(7000);
$("#ImageButtonDiv").show();
$("#adddiv").hide('slow');
});

}

// function add1click() {
$("#add1").click(function(event) {
$("#ImageButtonDiv").hide('slow');
$("#datatable").hide('slow');
$("#adddiv").fadeIn(000);
});

}

Service.cs:

[ServiceContract(Namespace = "")]
[AspNetCompatibilityRequirements(RequirementsMode = AspNetCompatibilityRequirementsMode.Allowed)]
public class Service
{
IDesignationController _designationController;
// Add [WebGet] attribute to use HTTP GET
[OperationContract]
public string GetDesignationData()
{
DataSet dt = GetDesignationViewData();
return GetJSONString(dt.Tables[0]);
}
public string GetJSONString(DataTable Dt)
{
string[] StrDc = new string[Dt.Columns.Count];
string HeadStr = string.Empty;
for (int i = 0; i < Dt.Columns.Count; i++) { StrDc[i] = Dt.Columns[i].Caption; HeadStr += "\"" + StrDc[i] + "\" : \"" + StrDc[i] + i.ToString() + "¾" + "\","; } HeadStr = HeadStr.Substring(0, HeadStr.Length - 1); StringBuilder Sb = new StringBuilder(); Sb.Append("{\"" + Dt.TableName + "\" : ["); for (int i = 0; i < Dt.Rows.Count; i++) { string TempStr = HeadStr; Sb.Append("{"); for (int j = 0; j < Dt.Columns.Count; j++) { if (Dt.Rows[i][j].ToString().Contains("'") == true) { Dt.Rows[i][j] = Dt.Rows[i][j].ToString().Replace("'", ""); } TempStr = TempStr.Replace(Dt.Columns[j] + j.ToString() + "¾", Dt.Rows[i][j].ToString()); } Sb.Append(TempStr + "},"); } Sb = new StringBuilder(Sb.ToString().Substring(0, Sb.ToString().Length - 1)); Sb.Append("]}"); return Sb.ToString(); } public DataSet GetDesignationViewData() { try { string connectionString = System.Configuration.ConfigurationManager.ConnectionStrings["connectionString"].ConnectionString; return SqlHelper.ExecuteDataset(connectionString, CommandType.StoredProcedure, DataTemplate.spDesignation_View); } catch (Exception err) { throw err; } } [OperationContract] public bool SetDesignationInsertData(string name,string description) { try { string connectionString = System.Configuration.ConfigurationManager.ConnectionStrings["connectionString"].ConnectionString; SqlParameter[] _spParams = new SqlParameter[3]; _spParams[0] = new SqlParameter(DataTemplate.paramName, name); _spParams[1] = new SqlParameter(DataTemplate.paramDescription, description); _spParams[2] = new SqlParameter(DataTemplate.paramCreatedDate, System.DateTime.Now); if (SqlHelper.ExecuteNonQuery(connectionString, CommandType.StoredProcedure, DataTemplate.spDesignation_Create, _spParams) > -2)
{
return true;
}
else
{
return false;
}
}
catch (Exception err)
{
throw err;
}

}
// Add more operations here and mark them with [OperationContract]
}