C++ classes in C# via a DLL

[Resnymph]

Hello,

I am trying to write a GUI in Visual C# which controls a C++ DLL, specifically getting hold of C++ objects and editing them via the C# propertygrid controls.

- The first part of the question is 'is this actually possible'?

I know I can use wrapper functions to return an object and marshall it but doesn't that essentially require me re-coding all of the classes in C#? All I want to do I have access to the properties so it seems a little extreme (as well as requiring multiple changes if I change a class).

- To hopefully avoid having to re-code everything, I saw that you can export a C++ class to a DLL but have had no luck in accessing its member functions or properties.

Here is the snippet of code I am attempting to get working:

C++ Class

#define LIB_IMPORT __declspec(dllimport)
#define LIB_EXPORT __declspec(dllexport)

namespace TestNamespace
{
class LIB_EXPORT TestClass;

	public class TestClass
	{
	
	public:

		TestClass()
		{
		}

		virtual ~TestClass()
		{
		};

		virtual int GetIntValue() 
		{ 
			return value; 
		}

	private:
		int value;
	};
}

C# access

using System;
using System.Collections.Generic;
using System.Windows.Forms;
using System.Runtime.InteropServices;
using TestNamespace;

namespace DLL
{
    static class Program
    {
        /// <summary>
        /// The main entry point for the application.
        /// </summary>
        [STAThread]
        static void Main()
        {
            TestClass c = new TestClass();
            Application.EnableVisualStyles();
            Application.SetCompatibleTextRenderingDefault(false);
            Application.Run(new Form1());
        }
    }
}

Whilst this code does compile, TestClass c is just a struct that has been declared in metadata with no functions or variables/

Is what I am trying to do possible or am I completely off the mark?

(Also sorry if this is in the wrong place, I assumed that C# people might have more experience with linking dlls)

Any help would be much appreciated.