Getting type?

So I posted a question the other day about dynamically loading DLL components. And it works great if I know the type like this(whatever.whatever):

Assembly asm = Assembly.LoadFrom(openFileDialog1.FileName);
Type myType = asm.GetType("whatever.whatever");
UserControl uc = (UserControl)Activator.CreateInstance(myType);
uc.Name = "uc";
this.Controls.Add(uc); 

But now how would I do this without knowing the type before?

Thanks :)