dynamic validation does not work

[parshupooja]

hey all,

I have DataTable binded to Gridview . This Datatable contains Data from Database. Before binding it to Gridview I am adding extra line with few controls dynamically in it such as text box below. When page loads I see extra Text box on the bottom of gridview but Validation is not working. Any Idea?

I am calling this Function on each page load.

Private Sub AddControls()
Dim con As SqlConnection = New SqlConnection(ConfigurationManager.ConnectionStrings("ConnectionString").ConnectionString)
        Dim cmd1 As SqlCommand = New SqlCommand("sp_get", con)
        cmd1.CommandType = CommandType.StoredProcedure
        Dim da1 As SqlDataAdapter = New SqlDataAdapter(cmd1)
        Dim dt1 As DataTable = New DataTable
        da1.Fill(dt1)
        Dim dr1 As DataRow = dt1.NewRow
        dt1.Rows.InsertAt(dr1, 0)

       Dim txtqty As New TextBox
        txtqty.ID = "txtqtyextra"
        txtqty.Width = 20

        Dim validation As New RequiredFieldValidator
        validation.ID = "reqvaltxtqty"
        validation.ControlToValidate = txtqty.ID
        validation.ErrorMessage = "*"

        Dim custvalidation As New CompareValidator
        custvalidation.ID = "custvalidationtxtqty"
        custvalidation.ControlToValidate = txtqty.ID
        custvalidation.ErrorMessage = "Value should be greater than 0"
        custvalidation.Type = ValidationDataType.Integer
        custvalidation.Operator = ValidationCompareOperator.GreaterThan
        custvalidation.ValueToCompare = 0
GridView1.Rows(GridView1.Rows.Count - 1).Cells(2).Controls.Add(txtqty)
 End Sub