customizing default filters in Radgridview windows forms

Private Sub grd_ContextMenuOpening(sender As Object, e As ContextMenuOpeningEventArgs) Handles grd.ContextMenuOpening
        Dim i As Integer = 0
        Dim IgnoreOperator() As String = {"Ends with", "Equals", "not equal to", "no filter"}
        If DirectCast(e.ContextMenuProvider, Telerik.WinControls.UI.GridCellElement).ColumnInfo.FieldName = "AcctNbr" Then
            While i < e.ContextMenu.Items.Count
                If Not IgnoreOperator.Contains(e.ContextMenu.Items(i).Text, StringComparer.CurrentCultureIgnoreCase) Then
                    e.ContextMenu.Items(i).Visibility = Telerik.WinControls.ElementVisibility.Collapsed
                End If
                i = i + 1
            End While
        End If
    End Sub

Private Sub grd_FilterChanging(sender As Object, e As GridViewCollectionChangingEventArgs) Handles grd.FilterChanging
        dv.RowFilter =""
        If e.NewValue IsNot Nothing
        If DirectCast((DirectCast(e.NewItems, Object())(0)), Telerik.WinControls.Data.FilterDescriptor).[Operator] = Telerik.WinControls.Data.FilterOperator.IsEqualTo AndAlso DirectCast((DirectCast(e.NewItems, Object())(0)), Telerik.WinControls.Data.FilterDescriptor).PropertyName = "AcctNbr" Then
            Dim CurrentVal As String = CStr(e.NewValue)
            dv.RowFilter = "EnAcctNbr ='" & CurrentVal & "'"
        End If
        If DirectCast((DirectCast(e.NewItems, Object())(0)), Telerik.WinControls.Data.FilterDescriptor).[Operator] = Telerik.WinControls.Data.FilterOperator.IsNotEqualTo AndAlso DirectCast((DirectCast(e.NewItems, Object())(0)), Telerik.WinControls.Data.FilterDescriptor).PropertyName = "AcctNbr" Then
            Dim CurrentVal As String = CStr(e.NewValue)
            dv.RowFilter = "EnAcctNbr <>'" & CurrentVal & "'"
        End If
        End If