C# Generics How Can I get the type passed as an argument for a generic method with no object type as a parameter?

Question

I need a method to find the original type of an argument called for a generic method like this:

public GetGenericArgumentName<T>() where T : IFoo
{
        StackFrame fr = new StackFrame(0, true);
        StackTrace st = new StackTrace(fr);
        var ga = fr.GetMethod().GetGenericArguments();

        foreach (var item in ga)
        {
            Console.WriteLine(item.Name);
        }
}

But I couldn't get the original type at the caller.

Let's say, I have to derived classes from IFoo

public class Foo : IFoo {}
public class Foo2 : IFoo {}

If I call them with the following methods I expect these results:

/* 1 */ GetGenericArgumentName<Foo>()
/* 2 */ GetGenericArgumentName<Foo2>()

For the first one, I expected Foo as result, and for the second Foo2. What am I missing?

Answer 1

You don't need to use stack traces at all there - just use typeof(T) :

Console.WriteLine(typeof(T).Name);

That will print Foo for the first call and Foo2 for the second call.

This is simpler, more reliably and more efficient than going up the stack.