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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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; }
}

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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);
        }
    }
}

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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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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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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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I am writing few post on different type of delegates and this post also will be part of it. In this post I am going to write about Predicate delegate which is available from C# 2.0. Following is list of post that I have written about delegates.

1. Delegates in C#.
2. Multicast delegates in C#.
3. Func delegate in C#.
4. Action delegate in C#.

Predicate delegate in C#:

As per MSDN predicate delegate is a pointer to a function that returns true or false and takes generics types as argument. It contains following signature.

Predicate<T> – where T is any generic type and this delegate will always return Boolean value. The most common use of a predicate delegate is to searching items in array or list. So let’s take a simple example. Following is code for that.

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In last few posts about I have written lots of things about delegates and this post is also part of that series. In this post we are going to learn about Action delegates in C#.  Following is a list of post related to delegates.

1. Delegates in C#.
2. Multicast Delegates in C#.
3. Func Delegates in C#.

Action Delegates in c#:

As per MSDN action delegates used to pass a method as parameter without explicitly declaring custom delegates. Action Delegates are used to encapsulate method that does not have return value. C# 4.0 Action delegates have following different variants like following. It can take up to 16 parameters.

• Action – It will be no parameter and does not return any value.
• Action(T)
• Action(T1,T2)
• Action(T1,T2,T3)
• Action(T1,T2,T3,T4)
• Action(T1,T2,T3,T4,T5)
• Action(T1,T2,T3,T4,T5,T6)
• Action(T1,T2,T3,T4,T5,T6,T7)
• Action(T1,T2,T3,T4,T5,T6,T7,T8)
• Action(T1,T2,T3,T4,T5,T6,T7,T8,T9)
• Action(T1,T2,T3,T4,T5,T6,T7,T8,T9,T10)
• Action(T1,T2,T3,T4,T5,T6,T7,T8,T9,T10,T11)
• Action(T1,T2,T3,T4,T5,T6,T7,T8,T9,T10,T11,T12)
• Action(T1,T2,T3,T4,T5,T6,T7,T8,T9,T10,T11,T12,T13)
• Action(T1,T2,T3,T4,T5,T6,T7,T8,T9,T10,T11,T12,T13,T14)
• Action(T1,T2,T3,T4,T5,T6,T7,T8,T9,T10,T11,T12,T13,T14,T15)
• Action(T1,T2,T3,T4,T5,T6,T7,T8,T9,T10,T11,T12,T13,T14,T15,T16)

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We already know about delegates in C# and I have previously posted about basics of delegates in C#. Following are posts about basic of delegates I have written.

Delegates in C#
Multicast Delegates in C#

In this post we are going to learn about Func Delegates in C#. As per MSDN following is a definition.

“Encapsulates a method that has one parameter and returns a value of the type specified by the TResult parameter.”

Func can handle multiple arguments. The Func delegates is parameterized type. It takes any valid C# type as parameter and you have can multiple parameters as well you have to specify the return type as last parameters.

Followings are some examples of parameters.
Func<int T,out TResult>
Func<int T,int T, out Tresult>

Now let’s take a string concatenation example for that. I am going to create two func delegate which will going to concate two strings and three string. Following is a code for that.

using System;
using System.Collections.Generic;

namespace FuncExample
{
    class Program
    {
        static void Main(string[] args)
        {
            Func<string, string, string> concatTwo = (x, y) => string.Format("{0} {1}",x,y);
            Func<string, string, string, string> concatThree = (x, y, z) => string.Format("{0} {1} {2}", x, y,z);

            Console.WriteLine(concatTwo("Hello", "Jalpesh"));
            Console.WriteLine(concatThree("Hello","Jalpesh","Vadgama"));
            Console.ReadLine();
        }
    }
}

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Yesterday, One of my friends, Dharmendra ask me why C# does not support multiple inheritance. This is the question most of the people ask every time. So I thought it will be good to write a blog post about it. So why it does not support multiple inheritance?

I tried to dig into the problem and I have found the some of good links from C# team from Microsoft for why it’s not supported in it. Following is a link for it.

http://blogs.msdn.com/b/csharpfaq/archive/2004/03/07/85562.aspx


Also, I was giving some of the example to my friend Dharmendra where multiple inheritance can be a problem.The problem is called the diamond problem. Let me explain a bit. If you have class that is inherited from the more then one classes and If two classes have same signature function then for child class object, It is impossible to call specific parent class method.

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C# 4.0 language includes a new feature called Tuple. Tuple provides us a way of grouping elements of different data type. That enables us to use it a lots places at practical world like we can store a coordinates of graphs etc.

In C# 4.0 we can create Tuple with Create method. This Create method offer 8 overload like following. So you can group maximum 8 data types with a Tuple. Followings are overloads of a data type.

• Create(T1)- Which represents a tuple of size 1
• Create(T1,T2)- Which represents a tuple of size 2
• Create(T1,T2,T3) – Which represents a tuple of size 3
• Create(T1,T2,T3,T4) – Which represents a tuple of size 4
• Create(T1,T2,T3,T4,T5) – Which represents a tuple of size 5
• Create(T1,T2,T3,T4,T5,T6) – Which represents a tuple of size 6
• Create(T1,T2,T3,T4,T5,T6,T7) – Which represents a tuple of size 7
• Create(T1,T2,T3,T4,T5,T6,T7,T8) – Which represents a tuple of size 8

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I have used delegates in my programming since C# 2.0. But I have seen there are lots of confusion going on with delegates so I have decided to blog about it. In this blog I will explain about delegate basics and use of delegates in C#.

What is delegate?

We can say a delegate is a type safe function pointer which holds methods reference in object. As per MSDN it's a type that references to a method. So you can assign more than one methods to delegates with same parameter and same return type.

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