CODE EXAMPLE FOR CSHARP

c# extension

public static class MyClassExtension
{
  // This is the method you are adding to a class "MyClass"
  public static string GetValue(this MyClass myClass)
  {
    return value.toString();
  }
}

// This is how you can use it in other parts of your code
MyClass myClass = new MyClass();
string s = myClass.GetValue();