public void CloseDBConnection()
 {
     _ctx.Dispose();
 }
 void ThisAddIn_Shutdown(object sender, System.EventArgs e)
 {
     // Note: Outlook no longer raises this event. If you have code that
     //    must run when Outlook shuts down, see https://go.microsoft.com/fwlink/?LinkId=506785
     ctx.Dispose();
 }