Question

Is it possible to reflect on an explicit interface implementation from the call stack? I want to use this info to look up an attribute on the interface itself.

Given this code:

interface IFoo
{
    void Test();    
}

class Foo : IFoo
{
    void IFoo.Test() { Program.Trace(); }
}

class Program
{
    static void Main(string[] args)
    {
        IFoo f = new Foo();
        f.Test();
    }

    public static void Trace()
    {
        var method = new StackTrace(1, false).GetFrame(0).GetMethod();
        // method.???
    }
}

Specifically, in Trace(), I would like to be able to get to typeof(IFoo) from method.

In the watch window, if I look at method.ToString() it gives me Void InterfaceReflection.IFoo.Test() (InterfaceReflection is the name of my assembly).

How can I get to typeof(IFoo) from there? Must I use a name-based type lookup from the assembly itself, or is there a Type IFoo hidden somewhere in the MethodBase?

UPDATE:

Here’s the final solution, thanks to Kyte

public static void Trace()
{
    var method = new StackTrace(1, false).GetFrame(0).GetMethod();
    var parts = method.Name.Split('.');
    var iname = parts[parts.Length - 2];
    var itype = method.DeclaringType.GetInterface(iname);
}

itype will have the interface type for the implementing method. This will only work with explicit interface implementations, but that’s exactly what I need. Now I can use itype to query attributes attached to the actual interface type.

Thanks to everyone for their help.

Answer 1

Testing around with VS2010, I found DeclaringType, which gets the object type that contains the method, from where you can get the interfaces as Type objects.

    public static void Trace() {
        var stack = new StackTrace(1, true);
        var frame = stack.GetFrame(0);
        var method = frame.GetMethod();

        var type = method.DeclaringType;

        Console.WriteLine(type);
        foreach (var i in type.GetInterfaces()) {
            Console.WriteLine(i);
        }
    }

Returns:

TestConsole.Foo
TestConsole.IFoo

(I called the project TestConsole)