private static void CheckIfLast(Excel.Workbook Wb, ref bool Cancel)
{
try
{
Excel.Workbooks wbs = _xlApp.Workbooks;
int count = wbs.OfType <Excel.Workbook>()
.Count(wb => !wb.Equals(Wb) && wb.Windows[1].Visible);
if (count <= 1)
{
_xlApp.Quit();
Marshal.ReleaseComObject(_xlApp);
_xlApp = null;
}
}
catch { }
}