Change the visibility of label within a datalist - asp.net

Question

How can I change the visibility of a label with a datalist using asp.net and C#-4.0 ? I tried the following code but unfortunately it is not working:
protected void Page_Load(object sender, EventArgs e)
{
if (!IsPostBack)
{
viewall();
}
protected void viewall()
{
MySqlCommand objacess = new MySqlCommand();
objacess.CommandText = "select * from product_tbl ";
DataTable dobj = new DataTable();
dobj = objDataAccess.GetRecords(objacess);
for (int i = 0; i < dobj.Rows.Count; i++)
{
string d = dobj.Rows[i]["pdiscount"].ToString();
int di = Convert.ToInt32(d);
if (di > 0)
{
Label lbldisc = (Label)DataList1.FindControl("lbl_discount");
lbldisc.Visible=true;
}
}
DataList1.DataSource = dobj;
DataList1.DataBind();
}
When I try this I receive the following Error:
Error : Object reference not set to an instance of an object.

Answer 1

dear friend your code is not finding the lable control thats why its giving you this error and all our databound countrol are working on then indexes so change you this line
Label lbldisc = (Label)DataList1.FindControl("lbl_discount");
to the following
Label lbldisc = (Label)DataList1.item[i].FindControl("lbl_discount");

Answer 2

you need to write hide code after binding the values.
//bind value to datalist
DataList1.DataSource = dobj;
DataList1.DataBind();
//after binding hide the label
for (int i = 0; i < dobj.Rows.Count; i++)
{
string d = dobj.Rows[i]["pdiscount"].ToString();
int di = Convert.ToInt32(d);
if (di > 0)
{
Label lbldisc = (Label)DataList1.FindControl("lbl_discount");
lbldisc.Visible=true;
}
}