checkbox validation in side datalist

protected void sbmt_btn_Click1(object sender, ImageClickEventArgs e)

{

foreach (DataListItem item in divProducts.Items)

{

Label lbl_pro_nm = item.FindControl("lbl_pro_nm") as Label;

Label lbl_product_id = item.FindControl("lbl_product_id") as Label;

DropDownList drop_quantity = item.FindControl("drop_quantity") as DropDownList;

h_productId.Value = lbl_product_id.Text;

CheckBox cb = item.FindControl("chkbox") as CheckBox;

if (cb != null)

{

if (cb.Checked == true)

{

objAdmin.wholesale_cartId = 0;

objAdmin.wholesale_clientFkId = int.Parse(h_wholesaleId.Value.ToString());

objAdmin.cat_f_kid = int.Parse(Session["cat_id"].ToString());

objAdmin.product_ka_naam = lbl_pro_nm.Text;

objAdmin.quantity = int.Parse(drop_quantity.SelectedValue.ToString());

objAdmin.product_ki_fk_id = int.Parse(h_productId.Value.ToString());

objAdmin.whole_category_fkid = int.Parse(Session["whole_category_fkid"].ToString());

Label2.Font.Size = 10;

Label2.Text += lbl_pro_nm.Text + "-" + int.Parse(drop_quantity.SelectedValue.ToString())+ "
";

Label3.Text = "?Thanks for considering our shop for your wholesale requirements successfully insert.
We will contact you within next few hours on your mail..";

DataSet ds = objAdmin.InsertWholesaleCartItem();

cb.Checked = false;

sbmt_btn.Visible = false;

//Button1.Visible = true;

}

//Response.Redirect("WholesaleOrder.aspx");

}

else

{

lblerror.Text = "Please select any item !!";

}

}