Dear All
I am working with VS2005, C#, Developer tool kit, GP 10.
I am trying to use Continuum API to handle the response of Dialog Box 
because I can't do that using Developer tool kit.
So I did create a new application "Microsoft Dynamics GP Add-in" C#
I have this error: "Specified cast is not valid"
I build my solution and I add the DLL in this path: C:\Program 
Files\Microsoft Dynamics\GP\AddIns
Please I need your advise please.
And I wrote the below Code
using System;
using System.Collections.Generic;
using System.Text;
using Microsoft.Dexterity.Bridge;
using Microsoft.Dexterity.Applications;
namespace HowToTestContinuumAPI
{
    public class GPAddIn : IDexterityAddIn
    {
        // IDexterityAddIn interface
        public static Dynamics.Application GPAPP = new Dynamics.Application();
        public GPCallbackClass GPCallBack = new GPCallbackClass();
        enum focus_type
        {
            PRE = 0, CHANGE, POST, PRINT, ACTIVATE, FILL, INSERT,
            DELETE, MODAL_DIALOG         }
        enum attach_type { Before = 1, After }        
        public void Initialize()
        {        
        //Dynamics.DIALOG_RESPONSE
        
        GPAPP.RegisterFocusTrigger("window 'IV_Transaction_Lot_Numbers' of 
form 'IV_Transaction_Entry'",
            8, 1, GPCallBack, "POP_Lot_Entry_Dialogs");        
        }
GPAPP.SetParamHandler(GPCallBack);
    } 
}
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////////////////////////////////////////////////////////////////////////////////////////////////
using System;
using System.Collections.Generic;
using System.Text;
namespace ContinuumAPIProjectCSharp
{
    public class GPCallbackClass
    {
        public GPCallbackClass()
        {
        }
        public void POP_Lot_Entry_Dialogs(int dialogType, string prompt, ref 
string
        control1, ref string control2, ref string control3, ref int answer)
        {
            if (dialogType == 0 && prompt == "Are you sure you want to 
remove all lot numbers?")
            {
                answer = 0;
                HowToTestContinuumAPI.GPAddIn.GPAPP.StopProcessing();
            }
        }
    }
}