I'm in deep water now. The item deletion has been worked fine but suddenly
stop working. The ItemRemove event stops firing. But the add and change
still work fine. I don't know what cause that.

I do declare variables in the class level, following the advices in the
article "mstehle: The CDOs and CDONTS of Messaging Development"
http://blogs.msdn.com/mstehle/archiv...op-firing.aspx.

Here is my code:

public partial class ThisAddIn
{
// appointment related
private Outlook.Explorer explorer;
private Outlook.Items items;

private void ThisAddIn_Startup(object sender, System.EventArgs e)
{
try
{
/******* appointment related event handler registration
*********/

//explorer = this.Application.ActiveExplorer();
//explorer.SelectionChange += new
Outlook.ExplorerEvents_10_SelectionChangeEventHand ler(ThisAddIn_SelectionChanged);

//openInspectors = this.Application.Inspectors;
//openInspectors.NewInspector += new
Outlook.InspectorsEvents_NewInspectorEventHandler( ThisAddIn_NewInspector);

Outlook._NameSpace ns =
this.Application.GetNamespace("MAPI");
Outlook.MAPIFolder calendarFolder =
ns.GetDefaultFolder(Outlook.OlDefaultFolders.olFol derCalendar);
items = calendarFolder.Items;

items.ItemAdd += new
Outlook.ItemsEvents_ItemAddEventHandler(ThisAddIn_ CalenmdarItemAdded);
items.ItemChange += new
Outlook.ItemsEvents_ItemChangeEventHandler(ThisAdd In_CalenmdarItemChanged);
items.ItemRemove += new
Outlook.ItemsEvents_ItemRemoveEventHandler(ThisAdd In_CalenmdarItemRemoved);
}
catch (Exception ex)
{
...
}
}

private void ThisAddIn_CalenmdarItemAdded(object item)
{
}

private void ThisAddIn_CalenmdarItemChanged(object item)
{
}

private void ThisAddIn_SelectionChanged()
{
}

private void ThisAddIn_CalenmdarItemRemoved()
{
}

private void ThisAddIn_NewInspector(Outlook.Inspector newInspector)
{
Marshal.ReleaseComObject(newInspector);
}