Extension Method in C#

  

protected void Button1_Click(object sender, EventArgs e)

{

            string a ="AP";

            a.DoChange("A", "P");
    

       //it will retun  APAPAjay

}

 

public static class TestExtension

{

  public static string DoChange(this string x, string a,string B)

  {

     return x + a + b + "Ajay";

  }

}