Restrict parameter to Controls and Forms in C#

I think this is what you require
where T: Control, Form

See this for more info.
https://docs.microsoft.com/en-us/dotnet/csharp/programming-guide/generics/constraints-on-type-parameters

I'd been puzzled by the request (it is ambiguous, control and form objects - does it mean all controls including forms or the control must be a form?).  The link provided should show all possibilities for the generic and their combinations.

I've made a quick test here.  (Guess who doesn't use the where clause that much and misunderstood the docs).

My first comment is wrong, it won't compile.

Thanks for all the input. You are right that Control also includes Form. I found that out just after I posted.

Regarding extension, that example was actually not relevant for my case since I use this to set one control edge (top, left, width, height) relative to another. Building a class out of all these relatives to resize controls on a form when the forms size changes in the form resize event.

David, while I appreciate the points.  I believe that gr8gonzo deserves credit as well.

-saige-

I agree with it_saige, gr8gonzo was the first to point out Forms are Controls


ps.  Should anyone require completely unconnected classes in a generic then this (rather theoretical example) is a way to do it.  Provide a dummy interface and have each class implement the interface even if it doesn't actually do anything.

        private void button1_Click(object sender, EventArgs e)
        {
            foo2<X>(new X());
            foo2<Y>(new Y());
        }




        private void foo2<T>(T ob) where T:IFoo2
        {

        }


    public interface IFoo2
    {
        void Z();
    }

    public class X : IFoo2
    {
        public X() { }
        public void Z() { }
    }

    public class Y : IFoo2
    {
        public Y() { }
        public void Z() { }
    }