主题：帮我看看这段代码有没有问题,没有反应!

   Dim UserIsRole As String = e.Form.Controls("UserIsRole").Value

   Dim cmd As New SQLCommand
    Dim dt As DataTable
     cmd.C
    cmd.CommandText = "SELECT * From {权限管理}"
    dt = cmd.ExecuteReader()
    If dt.DataRows.Count > 0 Then
        For Each dr As DataRow In dt.Select("用户名='"& _UserName & "'And 角色 ='"  & UserIsRole "'")
                If dr.IsNull("列名") Then
                Tables(dr("表名")).Visible = Not dr("不可见")
                Tables(dr("表名")).AllowEdit = Not dr("不可编辑")
            Else
                Tables(dr("表名")).Cols(dr("列名")).Visible = Not dr("不可见")
                Tables(dr("表名")).Cols(dr("列名")).AllowEdit = Not dr("不可编辑")
            End If
       ' Next
    End If