Drawable wrapper?

[Anonymous]

I have a custom AcGiDrawable entity that I want to wrap in .Net. All this is done and compiles fine but when I try to instance the object I get the message "Cannot create an instance of the abstract class or interface '....'.

Any ideas why this would be an issue. I have several custom entities (derived from AcDbEntity and AcDbObject) that aren't a problem, but for this one, problems arise.

#pragma once

#include "mgdinterop.h"
#include "..\InForm.Dbx\ReferenceIndicator.h"

using namespace System;
using namespace Autodesk::AutoCAD::DatabaseServices;
using namespace Autodesk::AutoCAD::Runtime;
using namespace Autodesk::AutoCAD::Geometry;
using namespace Autodesk::AutoCAD::GraphicsInterface;
using namespace Autodesk::AutoCAD::GraphicsSystem;
using namespace inform::dbx;

namespace aag = Autodesk::AutoCAD::GraphicsInterface;
namespace gs = Autodesk::AutoCAD::GraphicsSystem;

namespace InForm { namespace Dbx { namespace Net 
{
	[Autodesk::AutoCAD::Runtime::Wrapper("ReferenceIndicator")]
	public ref class ReferenceIndicatorWrapper : aag::Drawable
	{
#pragma region " Constructor "
		public:
			ReferenceIndicatorWrapper(void);
			ReferenceIndicatorWrapper(System::IntPtr ent, bool autoDel);
#pragma endregion

#pragma region " Internal Object "
	private:
		inline inform::dbx::ReferenceIndicator* GetInternalObject()
		{
			return static_cast<inform::dbx::ReferenceIndicator*>(UnmanagedObject.ToPointer());
		}
#pragma endregion

#pragma region " Public Methods "
		public:
			void Initialize(gs::View^ v, gs::Model^ m)
			{
				inform::dbx::ReferenceIndicator* p = GetInternalObject();
				if(p)
				{
					AcGsView* view = static_cast<AcGsView*>(v->UnmanagedObject.ToPointer());
					AcGsModel* model = static_cast<AcGsModel*>(m->UnmanagedObject.ToPointer());

					p->Initialize(view, model);
				}
			}
#pragma endregion
	};
}}}

#include "stdafx.h"
#include "ReferenceIndicatorWrapper.h"

using namespace InForm::Dbx::Net;

ReferenceIndicatorWrapper::ReferenceIndicatorWrapper(void)
	: aag::Drawable((System::IntPtr)new inform::dbx::ReferenceIndicator(), true)
{
}

ReferenceIndicatorWrapper::ReferenceIndicatorWrapper(System::IntPtr ent, bool autoDel)
	: aag::Drawable(ent, autoDel)
{
}

[DiningPhilosopher]

Just guessing, but it looks like the managed runtime is trying to create an instance of the base type (Drawable), which is abstract.  I assume you've derived from an AcRxClass* and have implemented AcMgObjectFactory and that you're calling rxinit()