Telerik Radgrid控制问题

Question

Protected Sub GrdCodes_ItemDataBound(ByVal sender As Object, ByVal e As GridItemEventArgs) Handles grdCodes.ItemDataBound
Try
  If (TypeOf e.Item Is GridDataItem) Then
    Dim item = DirectCast(e.Item, GridDataItem)
    Dim btnDelete = DirectCast(item("DeleteColumn").Controls(0), LinkButton)
    Dim btnEdit = DirectCast(item("EditColumn").Controls(0), LinkButton)
    btnDelete.Visible = HasRights()
    btnEdit.Visible = HasRights()
  End If
  If (TypeOf e.Item Is GridEditableItem AndAlso DirectCast(e.Item, GridEditableItem).IsInEditMode) AndAlso Not TypeOf e.Item.DataItem Is GridInsertionObject Then
            Dim editedItem = DirectCast(e.Item, GridEditableItem)
            Dim txtBc = DirectCast(e.Item.FindControl("Barcode").Controls(0), TextBox)
            txtBc.Enabled = False
  End If
Catch ex As Exception
  Logger.WriteToLog(LoggingBase.eLoggingSeverity.eErrorSeverity, "GrdCodes_ItemDataBound failed", ex, Now)
End Try
End Sub

  

txtBc.Enabled错误= False，未设置对象引用错误

我们需要在编辑模式下禁用特定的文本框 但失败并捕获了异常