I know I can receive messages with the code below in c#, how do I send to vb6, and receive in vb6, and send from vb6? [System.Security.Permissions.PermissionSet(System.Security.Permissions.SecurityAction.Demand, Name = "FullTrust")] protected override void WndProc(ref Message m) { int _iWParam = (int)m.WParam; int _iLParam = (int)m.LParam; switch ((ECGCardioCard.APIMessage)m.WParam) { // handling code goes here } base.WndProc(ref m); }