i define a client script for define the 2 cell value when i edit another cell,the value is came from the fuction name getPCode,it genearate a unique value in the table,here is the code :

 <script type="text/javascript" language="javascript">
        function BeforeEnterEditMode(gridName,cellID,newValue)
        {
              //get the cell
              var cell = igtbl_getCellById(cellID);
              var value1 = cell.Row.getCell(0).getValue();
              var sessionID = "<%=getSession() %>";
              var dcode = "<%=getPCode() %>";

                if (value1 == null)
                {
                    cell.Row.getCell(0).setValue(sessionID);
                    sessionID = null;
                    cell.Row.getCell(1).setValue(dcode);
                    dcode = null;
                    cell.endEdit();
                }
                else {
                    cell.Row.getCell(1).setValue("789");
                }
                return 0;
        }
    </script> 

i define the fuction getPCode in my .cs file ,as this :

   protected string getPCode()
    {
        string PCode = string.Empty;
        //do some thing in db
        return PCode;
    } 

i  track the source code and find this getPCode() only one time,when i add a new empty row,the dcode value is the last value because the fuction getPCode() don't run,so can anybody tell me why?