How to Validate Column with Same Value? - asp.net

Question

How to validate the column with same value, i try with this code :
protected void ASPxGridView1_RowValidating(object sender, DevExpress.Web.Data.ASPxDataValidationEventArgs e)
{
XPQuery<Inventory_Library.Inventory.t_barang_master> q = new XPQuery<Inventory_Library.Inventory.t_barang_master>(ses);
List<Inventory_Library.Inventory.t_barang_master> lst = (from o in q
where (o.nama_barang == e.OldValues["nama_barang"] && o.kode_barang == e.OldValues["kode_barang"])
select o).ToList<Inventory_Library.Inventory.t_barang_master>();
if (lst.Contains(e.OldValues["nama_barang"]))
{
e.RowError = "Nama barang yang anda masukkan telah terdaftar dalam sistem";
}
else if (lst.Contains(e.OldValues["kode_barang"]))
{
e.RowError = "Kode barang yang anda masukkan telah terdaftar dalam sistem";
}
}
but that's not work, how to solve this problem, thanks for the answer

Answer 1

problem solve, if you find the same problem with me, you can use this code:
protected void ASPxGridView1_RowValidating(object sender, DevExpress.Web.Data.ASPxDataValidationEventArgs e)
{
XPQuery<Inventory_Library.Inventory.t_kategori> q = new XPQuery<Inventory_Library.Inventory.t_kategori>(ses);
List<Inventory_Library.Inventory.t_kategori> lst = (from o in q
where (o.kategori == e.NewValues["kategori"])
select o).ToList<Inventory_Library.Inventory.t_kategori>();
if (lst.Count > 0)
{
e.RowError = "Kategori yang anda masukkan telah terdaftar dalam sistem";
}
}