void PrintInvSumm(DateTime printdate1, DateTime printdate2)
{
IPrintDocument prtInv = PrintDocManager.GetPrintSummary <PrintSummary>();
prtInv.SetNoOfCopy(1);
Hashtable para = new Hashtable();
para.Add("DateStart", printdate1);
para.Add("DateEnd", printdate2);
prtInv.SetExtraPara(para);
prtInv.SetCallingActivity(this);
prtInv.StartPrint();
Toast.MakeText(this, prtInv.GetErrMsg(), ToastLength.Long).Show();
}