Nicolas Penin

Generics in C#

Have you already used generics in C# ? Yes ? Then you may already have struggled with the issues I'm going to talk about.

When you are in a generic method, you may want to cast your generic object into another type to do some specific treatment :

    class Program
    {
        static void Main(string[] args)
        {
            GenericMethod<Class1>(new Class1());
        }

        static T GenericMethod<T>(T item)
        {
            Class1 c1 = ((Class1)item);
            return item;
        }
    }

However when you do this, you have the compiler that says you "cannot convert type 'T' to 'Class1'". The tip is to use the as keyword, and the compiler wont bore you anymore :

    class Program
    {
        static void Main(string[] args)
        {
            GenericMethod<Class1>(new Class1());
        }

        static T GenericMethod<T>(T item)
        {
            Class1 c1 = item as Class1;
            return item;
        }
    }

One more thing really useful : when you want to use generic methods, you do not necessarly need to specify the generic type. If the method expect this generic type as parameter, the compiler can infer it :

	class Program
	{
		static void Main(string[] args)
		{
			GenericMethod(new Class1());
		}

		static T GenericMethod<T>(T item)
		{
			Class1 c1 = item as Class1;
			return item;
		}
	}

Hope it was useful. Have fun, and keep your little fingers brawny.