Question

I have a DynamicObject-based class that implements an interface dynamically (via TryGet* and TryInvoke*). I want to call the methods that it implements using reflection. The problem is that it throws a TargetException (Object does not match target type).

Like I said, it’s dynamic, so it forwards the calls via a series of connections as text to another program, which then calls the destination method using reflection. It is basically a proxy class. The method names are known at compile time (because of the interface), but are called externally.

typeof(ITelescope).GetMethod(Console.ReadLine()).Invoke(prox,null);

ITelescope is the interface, prox is the dynamic object.

Answer 1

Although you can not invoke a dynamic method with reflection, you can invoke TryGet…/TryInvoke… methods of DynamicObject which in turn execute your dynamic method…

dynamic obj = new MyDyn();
Console.WriteLine(obj.Text);

string methodName = "YourDynamicMethod";                    

var p1 = new ParameterModifier(2);
p1[0] = false; p1[1] = true;

var args = new object[] { new MemberBinder(methodName, true), null };

var res = typeof(DynamicObject).InvokeMember(
    "TryGetMember",
    BindingFlags.Instance | BindingFlags.InvokeMethod | BindingFlags.Public,
    null,
    obj,
    args,
    new ParameterModifier[] { p1 },
    null,
    null);

var result = args[1];

---

public class MyDyn : DynamicObject
{
    public override bool TryGetMember(GetMemberBinder binder, out object result)
    {
        result = "#" + binder.Name + "#";
        return true;
    }
}

public class MemberBinder : GetMemberBinder
{
    public MemberBinder(string name, bool ignoreCase) : base(name, ignoreCase)
    {
    }

    public override DynamicMetaObject FallbackGetMember(DynamicMetaObject target, DynamicMetaObject errorSuggestion)
    {
        throw new NotImplementedException();
    }
}