Add methods to base class c#

Question

Is that possible to add methods to Base classes like List? or others? I really need to add method to generic list class if it has MyClass type. like this: List<MyClass>.FindCoolStuff() or List<MyClass>.SetValueByName()

thanks

Answer 1

No, but you can use an extension method.

public static class ListExtensions
{
    public static IEnumerable<T> DoCoolStuff<T>(this List<T> collection)
    {
        // Do cool stuff
    }
}

From MSDN: In your code you invoke the extension method with instance method syntax.

var awesomeList = new List<string>();

var awesomestuff = awesomeList.DoCoolStuff();

Answer 2

While you cannot add methods to a class, you can give the illusion of doing so using extension methods ( http://msdn.microsoft.com/en-us/library/vstudio/bb383977.aspx). Note that these methods will only appear on instances of that class or interface, not on the type (like static methods).

Answer 3

If you want to restrict it to working only for MyClass, you can use the where keyword; so using the example above

public static class ListExtensions
{
    public static IEnumerable<T> DoCoolStuff<T>(this List<T> collection) where T : MyClass
    {
        // Do cool stuff
    }
}