How to use Reflection to Invoke an Overloaded Method in .NET

Question

Is there a way to Invoke an overloaded method using reflection in .NET (2.0). I have an application that dynamically instantiates classes that have been derived from a comm

Answer 1

Yes. When you invoke the method pass the parameters that match the overload that you want.

For instance:

Type tp = myInstance.GetType();

//call parameter-free overload
tp.InvokeMember( "methodName", BindingFlags.InvokeMethod, 
   Type.DefaultBinder, myInstance, new object[0] );

//call parameter-ed overload
tp.InvokeMember( "methodName", BindingFlags.InvokeMethod, 
   Type.DefaultBinder, myInstance, new { param1, param2 } );

If you do this the other way round(i.e. by finding the MemberInfo and calling Invoke) be careful that you get the right one - the parameter-free overload could be the first found.

Answer 2

Use the GetMethod overload that takes a System.Type[], and pass an empty Type[];

typeof ( Class ).GetMethod ( "Method", new Type [ 0 ] { } ).Invoke ( instance, null );

Answer 3

You have to specify which method you want:

class SomeType 
{
    void Foo(int size, string bar) { }
    void Foo() { }
}

SomeType obj = new SomeType();
// call with int and string arguments
obj.GetType()
    .GetMethod("Foo", new Type[] { typeof(int), typeof(string) })
    .Invoke(obj, new object[] { 42, "Hello" });
// call without arguments
obj.GetType()
    .GetMethod("Foo", new Type[0])
    .Invoke(obj, new object[0]);