void f_ApprovalDone(object sender, ApprovalEventArgs e)
 {
     if (e.ApproverId == 0)
     {
         ClientHelper.ShowErrorMessage("Invalid approver.");
     }
     else
     {
         AddPurchaseReturn();
     }
 }
 void form_ApprovalDone(object sender, ApprovalEventArgs e)
 {
     if (e.ApproverId == 0)
     {
         ClientHelper.ShowErrorMessage("Invalid approver.");
     }
     else
     {
         approver = e.ApproverId;
         SaveReturn();
     }
 }