主题：请帮修正一下代码

If e.DataCol.Name = "来电_单位" OrElse e.DataCol.Name = "通知_办报员" Then
    Dim dr As DataRow
    Dim Filter As String
    Dim a As String
    Dim b As String
    Filter = "[单位_名称] = '" & e.DataRow("通知_单位") & "' And [用户_姓名] = '" & e.DataRow("通知_办报员") & "'"
    dr = DataTables("人员管理").Find(Filter)
    If dr IsNot Nothing Then
        If dr.IsNull("电话_手机2")  Then
            a = ""
        Else
            a = ","
        End If
        If dr.IsNull("电话_手机3") Then
            b = ","
        Else
            b = ""
        End If
        e.DataRow("通知_办公电话") = dr("电话_办公室")
        e.DataRow("通知_移动电话") = dr("电话_手机1") & a & dr("电话_手机2") & b & dr("电话_手机3")
    Else
        e.DataRow("通知_办公电话") = Nothing
    End If
End If