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Anonymous Methods in C# .NET


Anonymous Methods in C#

An anonymous method is a method which doesn’t contain any name, it is introduced in C# 2.0. It is useful when the user wants to create an inline method and also wants to pass parameter in the anonymous method like other methods. An Anonymous method is defined using the delegate keyword and the user can assign this method to a variable of the delegate type.

Syntax of Anonymous method

Anonymous methods are declared with the creation of the delegate instance, with a delegate keyword. For example
delegate(parameterList)
{
    // Code..
};

Example of Anonymous method

using System;

namespace LegalManagementSystem.Models
{
    public delegate void CsharpArticle(string article);
    public class CsharpnaijaAnonymous
    {
        public static void Main()
        {
            // An anonymous method with one parameter
            CsharpArticle p = delegate (string article)
            {
                Console.WriteLine("My favorite article in                    Csharp naija blog is: {0}",article);
            };
            p("Anonymous method in C#");
        }
    }
}

 Important Points:

·         This method is also known as inline delegate.
·         Using this method you can create a delegate object without writing separate methods.
·         This method can access variable present in the outer method. Such type of variables is known as Outer variables. As shown in the below example art is the outer variable.

You can also pass anonymous method to another method which accepts delegate as a parameter. As shown in the below example:

using System;

namespace LegalManagementSystem.Models
{
    public delegate void CsharpArticle(string article);

    public delegate void ReadArticle(string x);
    public class CsharpnaijaAnonymous
    {
        // identity method with two parameters
        public static void CsharpArticle(ReadArticle article,
                                  string articleDesc)
        {
            articleDesc = " Delegates and Events ";
            article(articleDesc);
        }
        public static void Main()
        {
            // Here anonymous method pass as 
            // a parameter in CsharpArticle method
            CsharpArticle(delegate (string articleDesc) {
                Console.WriteLine("The Anonymous method is a good concept in understanding of {0}", articleDesc);
            }, "in C#");
        }
    }
}

Notes

·         In anonymous methods, you are allowed to remove parameter-list, which means you can convert an anonymous method into a delegate.
·         The anonymous-method-block means the scope of the parameters in the anonymous method.
·         An anonymous method does not contain jump statements like ‘goto’, break, or continue.
·         An anonymous method does not access unsafe code.
·         An anonymous method does not access in, ref, and out parameter of the outer scope.
·         You cannot use an anonymous method to the left side of the ‘is’ operator.
·         You can also use an anonymous method as an event handler.

We will see how to use anonymous method as an event handler in the next article

References

1.     Geeksforgeeks
2.     TutorialPoint

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