Here is a C# example: Create a COM object with events using C# and implement in a VB6 Application.
Step #1: Define COM interfaces
Need to create two interfaces - 1 class interface and a events interface
Public Class Interface: IMyClass
using System;
using System.Drawing;
using PicasaBloggerUserControls;
using System.Runtime.InteropServices;
namespace MyApp
{
[Guid("xxxxxxxx-yyyy-zzzz-aaaa-bbbbbbbbbbbb")]
[InterfaceType(ComInterfaceType.InterfaceIsIDispatch)]
public interface IMyClass
{
void GetDRCUpdate(string url, int majorVer, int minorVer, int RevisionVer, bool GetLatest);
}
}
Public Interface defining the events: IMyClassEvents
using System;
using System.Collections.Generic;
using System.Runtime.InteropServices;
using System.Text;
namespace MyApp
{
[InterfaceType(ComInterfaceType.InterfaceIsIDispatch)]
[Guid("xxxxxxxx-yyyy-zzzz-aaaa-bbbbbbbbbbbb")]
public interface IMyClassEvents
{
void DownloadComplete();
void DownloadCancel(bool downloadfailed);
}
}
Step #2
Define Public class using class interface: winformUI
using System.Drawing;
using System.Windows.Forms;
using PicasaBloggerUserControls;
using System.Runtime.InteropServices;
namespace PicasaBloggerUI
{
[Guid("xxxxxxxx-yyyy-zzzz-aaaa-bbbbbbbbbbbb")]
[
ComSourceInterfaces("MyApp.PicasaBloggerEventsInterface"),
ClassInterface(ClassInterfaceType.None)
]
[ProgId("winformUI")]
public class winformUI :
{
public event FileDownloadDelegate DRCDownloadComplete;
public delegate void FileDownloadDelegate();
public event FileDownloadCancelDelegate DRCDownloadCancel;
public delegate void FileDownloadCancelDelegate(bool downloadfailed);
private frmDRCUpdate _DRCUpdater;
//ctor
public winformUI()
{
_DRCUpdater = new frmDRCUpdate();
_DRCUpdater.OnFileDownload += new frmDRCUpdate.FileDownloadDelegate(_DRCUpdater_OnFileDownload);
_DRCUpdater.OnFileDownloadCancel += new frmDRCUpdate.FileDownloadCancelDelegate(_DRCUpdater_OnFileDownloadCancel);
}
void _DRCUpdater_OnFileDownloadCancel()
{
if (null != DRCDownloadCancel)
{
DRCDownloadCancel(!_DRCUpdater.Successful);
}
}
void _DRCUpdater_OnFileDownload()
{
try
{
//MessageBox.Show("Download Successful");
DRCDownloadComplete();
}
catch
{
}
}
void IPicasaBlogger.GetDRCUpdate(string url, int majorVer, int minorVer, int RevisionVer, bool GetLatest)
{
_DRCUpdater = new frmDRCUpdate();
_DRCUpdater.OnFileDownload += new frmDRCUpdate.FileDownloadDelegate(_DRCUpdater_OnFileDownload);
_DRCUpdater.OnFileDownloadCancel += new frmDRCUpdate.FileDownloadCancelDelegate(_DRCUpdater_OnFileDownloadCancel);
_DRCUpdater.Show();
_DRCUpdater.GetDRCUpdate(url, majorVer, minorVer, RevisionVer, GetLatest);
}
}
}
Step #3 Compile C# code and register the assembly:
REGASM MyApp.dll /tlb:com.MyApp.tlb
Now you are ready to add the COM object as a reference to a VB project.
1) Open VB6 project, select references and browse to locate of MyApp.tlb and add as a reference.
In a VB6 form Module
Private WithEvents oMyAppUI As MyApp.winformUI
Private Sub Form_Load()
Set oMyAppUI = New MyApp.winformUI
End Sub
Private Sub oMyAppUI_DownloadCancel(ByVal downloadfailed As Boolean)
If downloadfailed Then
MsgBox "Update Failed, please try again. If the failure persists, contact me at Gary.Kindel@gmail.com for assistance.", vbOKOnly
Else
MsgBox "You have the current version, no updates are available.", vbExclamation
End If
End Sub
Private Sub oMyAppUI_DownloadComplete()
If MsgBox("Do you want to exit and install the update?", vbYesNoCancel, "Exit DRC and run Update file") = vbYes Then
mApplyUpdate = True
Unload Me
End If
End Sub
