Set the selected value of RadCombobox on itemcommand of radgrid

if (e.CommandName == "Edt")
{
   ViewState["SerialOrder"] = strSerail.ToString();
   ViewState["Edit"] = "True";//this is used for data changed in edit mode
                        
   if (e.Item.Cells[6].Text != " " && e.Item.Cells[6].Text != "")
     txtBatch.Text = e.Item.Cells[6].Text;
   else
     txtBatch.Text = "";
   CheckBatchItem();//for check the batch item or not
   if (e.Item.Cells[9].Text != " " && e.Item.Cells[9].Text != "")
     txtQuantity.Text =e.Item.Cells[9].Text;
   else
     txtQuantity.Text = "";
   string strProductiondate = e.Item.Cells[7].Text;
   RadDatePicker StartRadProductionDate = new RadDatePicker();
   StartRadProductionDate = (RadDatePicker)DateCalenderProductDate.FindControl("StartDate");
   if (!string.IsNullOrEmpty(strProductiondate) && strProductiondate != " ")
   {
      StartRadProductionDate.SelectedDate = Convert.ToDateTime(strProductiondate);
   }
   else
   {
      StartRadProductionDate.Clear();
   }
   string strexpirydate =  e.Item.Cells[8].Text;
   RadDatePicker StartRadExpiryDate = new RadDatePicker();
   StartRadExpiryDate= (RadDatePicker)DateCalenderExpiryDate.FindControl("StartDate");
   if (!string.IsNullOrEmpty(strexpirydate) && strexpirydate != " ")
   {
      StartRadExpiryDate.SelectedDate = Convert.ToDateTime(strexpirydate);
   }
   else
   {
      StartRadExpiryDate.Clear();
   }
   ddlItem.SelectedValue = ((Label)e.Item.FindControl("lblfieldId")).Text;                        
   ddlItem.Enabled = false;