public void cost_Update(Object sender, DataGridCommandEventArgs e)
{
if(((TextBox)e.Item.Cells[2].Controls[0]).Text!="")
{
sql="UPDATE Cost SET CostStatus=@CostStatus,CostDateTime=@CostDateTime,
where CostID=@CostId";
}
else
{
sql="UPDATE Cost SET CostStatus=@CostStatus,CostDateTime=null,
where CostID=@CostId";
}