As we all know web pages are stateless pages and we need to use session variables in web application to maintain some session over page. Some time we divide our application into multiple layers for example business logic layer,database layer etc. This all layers will be a class library projects.

So when you have your applications divided into the multiple layers at that time you might need to use session variables in the class library projects. For that we are adding System.Web namespace as a reference to a class library project and then we can use session with HttpContext object. That’s works fine if your layers are going to be used in web application projects. But for example if you have service oriented architecture and your services also access your class libraries via non standard protocol i.e. WCF Service hosted on TCP/IP bindings. At that time sessions will not work.

Instead of that you should always use the parameters in method and avoid direct use of session variables. That parameters will passed either from the web application or from the services which is calling the class libraries.

Hope you liked it. Stay tuned for more..

In this post we are going to learn about difference between ‘All’ and ‘Any’ operator in Linq.

Difference between ‘All’ and ‘Any’ operator:

All operator checks whether all elements have met specific conditions or not while Any operator check whether there is any elements exist in collection or not?

So what we are waiting for Let’s take a example.

using System;
using System.Linq;

namespace ConsoleApplication1
{
    class Program
    {
        static void Main(string[] args)
        {
            int[] intArray = {1,2,3,4,5};
            bool result = intArray.All(i => i > 2);
            Console.WriteLine(result);
            result = intArray.Any();
            Console.WriteLine(result);
            Console.ReadLine();
        }
    }
}

In the above example you can see that I have created an integer array and then checked with both all and any operator. In first condition I have checked that whether elements are greater then 2 or not and same way I have checked with any operator that its contains any element or not?

Now let’s run that example. To see how its works.

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Few days back I came across “All” operator in Linq. I thought it will be good idea to write a blog post about it and share it with community.

All operator in linq:

It’s almost similar to select it returns all the element in the input sequence with matching condition in given predicate. Following is syntax for All.

public static bool All<TSource>( 
this IEnumerable<TSource> source, 
Func<TSource, bool> predicate)

It check the condition whether all the elements on collection matches given criteria and based on that it will return bool value.  It can be useful in scenario where we need to do some kind of validation whether all the elements of collection matches with certain condition or not.

So Let’s take a simple example. Following is a code for that.

using System;
using System.Linq;

namespace ConsoleApplication1
{
    class Program
    {
        static void Main(string[] args)
        {
            int[] intArray = {1,2,3,4,5};
            bool result = intArray.All(i => i > 2);
            Console.WriteLine(result);
            result = intArray.All(i => i < 6);
            Console.WriteLine(result);
        }
    }
}

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In this post, I am going to explain about default keyword in c#.

Introduction:

As per MSDN default keyword in C# used to assign the default value of the type. In some situation its comes very handy where we don’t want to create object and directly assign the default value of it.

The basic syntax of default is default(T) where t is any reference type of value type and If T is a value type, whether it will be  a numeric value or struct.

Default Keyword usage:

We can use Default keyword in variety of cases.

Assigning value to nullable Type:

We can use it to assign default value to nullable types like below.

using System;

namespace ConsoleApplication3
{
    class Program
    {
        static void Main() {
            int? i = default(int);
            Console.WriteLine(i);
        }
    }
}

Here output will be.

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In this post, I am going to explain how we can convert an generic list to simple int array with Help of Linq. Recently, I was working on an application and there I needed an Int array of for list of ids in generic list. I tried various methods and then with the help of ‘Select’ operator and ToArray method I have easily converted an generic list to the int array.

Lets take a simple example. I need a contact id list from a generic list of contacts and following is my contact class.

public class Contact
{
    public int ContactId { get; set; }
    public string Name { get; set; }
}

Now I have created a new GetContacts methods to create a new Generic List of Contacts.

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In this post we are going to see how we can use Response.Redirect(Redirecttion) in asp.net friendly URLs. Before some day I have written a post about ASP.NET Friendly URLs – Cleaner, SEO friendly URLs. On that post one reader ‘Ramesh’ asked me that how we can do redirection with ASP.Net friendly URLs. So this post is in reply to Him.

How to redirect a page to ASP.Net friendly URLs:

Actually!! there is nothing to learn. It’s very easy You can directly use the ‘Response.Redirect’ with the ASP.Net friendly URLs. The NuGet Package itself takes care of all the things. You just need to write the route name as a parameter in ‘Response.Redirect’ and you are done!!

Uh!! don’t believe me!!. Let’s take a sample example. I am going to use by default template with ASP.NET Friendly URLs.  So for this example I have created a ASP.Net button in Default template AboutUs.aspx page. Once the click of that button we are going to use ‘Response.Redirect’ for redirection and redirect this page to Contact Page. Following is a html code for that button.

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Search Engine optimization is one of the key factor for your site. If you spend millions of dollars on making your website looks good and bug free then also its possible that you will not get attention of search engine because of your URLs.  For example you’re having shopping cart created in asp.net and you have not optimized your URL then it will look like following.

www.foo.com ?Product.aspx?Category=1& Page=1

If you search engine read this URL then search engine will not know much about this URLs. Even normal people  who does not know querystring menaing(?Category=watch&Page=1) will not understand it. But If you have URL like following.

www.foo.com/prduct/category/watch/page/1

It’s easy to read and search engine and normal people will know that you are loading products that belongs to category watch and this is a first page.

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Before some days I have posted an blog about How to create overloaded web methods in asp.net web service? In this post I am going to explain how we can create overload methods in WCF(Windows Communication Foundation) service with C# language.

So let’s consider same Hello world example which we have used web service overload method. Let’s create two methods HelloWorld one is with name and another is without parameter. For WCF service we have to first create interface following is a code for that.

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SelectMany is an important operator in Linq. It takes each element of a sequence to an IEnumerable and flattens the resulting sequences into one sequence. You can find out more information about different overload list from the below link.

http://msdn.microsoft.com/en-us/library/system.linq.enumerable.selectmany.aspx

In this post I am going to explain How it can be really useful when you want to find list related to two entities. Practical example will be like a person can have multiple address and if you want to find list of addresses that are used with person then this SelectMany operator can be really useful.

So for this example First, I have create Address class with Street and Postalvcode property

public class Address
{
    public string Street { get; set; }
    public string PostalCode { get; set; }
}

Continue reading →

C# language provides many features and null-coalescing operator(??) is one of them. It’s a great operator to check whether object is null and if it is null then it will provide a default value. I have seen most of the people are not using while it’s a great feature. So I decided to write a blog about this.

You can find more information about null-coalescing operator from the below link.
http://msdn.microsoft.com/en-us/library/ms173224.aspx

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I was needed to convert an string array into the comma delimited string and the old way to do that is too with for loop. But I was sure that there should be some ready made function that will do this very easily.

After doing some research I have found string.Join. With the help of this we can easily an array into the comma delimited string.

String.join have two arguments one is separator and other one is either array or enumerable.

Following is a code for that.

namespace ConsoleApplication3
{
    class Program
    {
        static void Main() {
            string[] name = {"Jalpesh", "Vishal", "Tushar", "Gaurang"};
            string commnaDelmietedName = string.Join(",", name);
            System.Console.WriteLine(commnaDelmietedName);
        }
    }
}

Continue reading →

Recently I was using resharper to refactor some of my code and found that it was suggesting to use any() extension method instead of count() method in List<T>. I was really keen about performance and found that resharper was right. There is huge performance difference between any() and count() if you are using count() just to check whether list is empty or not.

Difference between Count() and Any():

In Count() method code will traverse all the list and get total number of objects in list while in Any() will return after examining first element in the sequence. So in list where we have many object it will be significant execution time if we use count().

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Problem:

Recently one of my friend was needed only first three rows of data table and so he asked me and I have multiple solutions for that. So thought it would be great idea to share with you guys.

Possible Solutions to problem:

There are two ways to solve this problem.

1. With normal for loop
2. With lamda expression and linq

1. With normal for loop:

Following is code from where we can get 3 rows of data table.

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I have already written lots of post about Visual Studio 2012 features and this post is also going to be part of that series. You can get whole series of post from the following link.

Visual Studio 2012 features

In this post we are going to talk about search and filters provided into the visual studio 2012. There are lots of emphasis there in search and filters in visual studio 2012.You can almost search every thing including errors also. There are different search options are available for that.

Quick launch search in visual studio:

Prior to previous edition in visual studio 2012 there was quick launch search given at the top of the visual studio. From here you can search for anything in solutions and even menu’s also. It will provide you a quick launch for that.

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Before C# 4.0 there was no on demand initialization by default. So at the time of declaration we need to create a value or object will be null or we have to create on demand initialization via coding.. But with C# 4.0 we now have lazy class. As per MSDN it support lazy initialization so it means if we use lazy class then it will initialize the object at the time of demand.

It is very useful for UI responsiveness and other scenario's.  Lazy initialization delays certain initialization and  it’s improve the start-up time of a application. In the earlier framework if we need this kind of functionality we have to do it manually via coding but from C# 4.0 onwards it have Lazy<T> class. With the Help of this we can improve the responsiveness of C# application. Following is a simple example.

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As we have written earlier we have now multi-core CPU for our computers and laptops and to utilize that we need to use threading in code. Now if we create thread and access same resource at same time then it will create a problem at that time locking become quite essential in any programming language.

Let’s consider a scenario. We are having a small firm of computers and each computer is shared by two employees and they need to use computer for putting their sales data in excel sheet. So they can not work together at same time and one has to work and other has to wait till first one complete the work. Same situation can be occurred in programming in where we are using same resource for multiple thread.

C# provides locking mechanism via lock keyword. It restricts code from being executed by more then one thread at a time. That is the most reliable way of doing multi threading programming.

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Yesterday I have written a blog post about Where I can find SQL Generated by Entity Framework? and same day I got request from one of the our reader Ramesh that how I can find SQL generated by Linq-To-SQL?. I thought its a good idea to write a blog post to share amongst all who need this instead of reply in comments.  In this post I am going to explain how we can get SQL generated by Linq-To-SQL.

For this post I am going to use same table like following. A customer table with two columns CustomerId and CustomerName.

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Few days back I was optimizing the performance with Entity framework and Linq queries and I was using LinqPad and looking SQL generated by the Linq or entity framework queries. After some point of time I got the same question in mind that how I can find the SQL Statement generated by Entity framework?

After some struggling I have managed to found the way of finding SQL Statement so I thought it would be a great idea to write a post about  same and share my knowledge about that. So in this post I will explain how to find SQL statements generated Entity framework queries.

To demonstrate the idea Let’s a very simple console application with C# and then  create a table called ‘Customer’ with CustomerId and CustomerName field in sql server.

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In c# 5.0 Microsoft has introduced a Caller information attribute. It’s a new feature that is introduced in C# 5.0 and very useful if you want to log your code activities. With the help of this you can implement the log functionality very easily. It can help any programmer in tracing, debugging and diagnostic of any application.
With the help of Caller Information we can get following information over there.

1. CallerFilePathAttribute: With help of  this attribute we can get full path of source file that contains caller. This will be file path from which contains caller at compile time.
2. CallerLineNumberAttribute:  With the help of this attribute we can get line number of source file which the method is called.
3. CallerMemberNameAttribute: With the help of this attribute we can get the method or property name of the caller.

Let’s write a simple example for that to see how its works. Following is a code for that.

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In today’s computing world  is all about Parallel processing. You have multicore CPU where you have different core doing different work parallel or its doing same task parallel. For example I am having 4-core CPU as follows. So the code that I write should take care of this. C# does provide that kind of facility to write code for multi core CPU with task parallel library. We will explore that in this post.

 

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