I cannot get my extension method to work (C#)

Question

Any ideas? I marked it as static but it's not working!

class ExtensionMethods
{
    public static int Add(this int number, int increment)
    {
        return number + increment;
    } 
}

Answer 1

You are missing a static on the class. The compiler should have told you this?

public static class ExtensionMethods

Answer 2

I think, it needs to be defined in a static class:

namespace MyNameSpace
{
    public static class ExtensionMethods
    {
        public static int Add(this int number, int increment)
        {
            return number + increment;
        } 
    }
}

You must also include a using MyNameSpace; in the code file you want to use them in, unless it is in the same namespace