Question

I recently wrote an Outlook plug-in (for use in Outlook 2010) for a client that syncs up their user’s Outlook databases with a third-party application. This works fine. However, one thing that the client wants to do is to leverage standard copy/paste functionality to duplicate records in Outlook. The issue is that I define a UserProperty for any Outlook record that has been sent to the third-party system (it stores the internal ID from the third-party system). When the client performs a copy/paste, this UserProperty is also copied (which is bad as it creates multiple records with the same third-party ID). I was wondering if there was some way to detect via code that a copy/paste was occurring and to make a modification in the record (removal of this UserProperty) prior to save. As they might perform this on Tasks, Appointments, or Contacts, I would need guidance that would apply across the board.

Per the suggestions below, I attempted to leverage BeforeItemPaste, as seen below:

private void ThisAddIn_Startup(object sender, System.EventArgs e) {
    Globals.ThisAddIn.Application.ActiveExplorer().BeforeItemPaste += new Outlook.ExplorerEvents_10_BeforeItemPasteEventHandler(Item_BeforeItemPaste);
}

private void Item_BeforeItemPaste(ref System.Object ClipboardContent,
    Microsoft.Office.Interop.Outlook.MAPIFolder Target, ref bool Cancel) {
    System.Windows.Forms.MessageBox.Show("Trying to paste");
}

The message appears the very first time I do a copy/paste, and then never again. I tried leveraging Application.Explorers, which theoretically gives me access to all Explorers in Outlook, but that didn’t give me access to the individual ones (Appointment, Task, Contact) that I was looking for (there was only one element in that ‘array’ when I debugged it). Also, I tried to access those specific Explorer items by invoking MAPIFolder.GetExplorer, but this always returned null.

Answer 1

Try to use Explorer.BeforeItemPaste event.