主题：三个字段相同 提示已经存在

Select Case e.DataCol.Name
    Case "货物名称","牌号","规格型号"
        Dim dr As DataRow
        dr = e.DataTable.Find("规格型号 = '" & e.NewValue & "'" And "货物名称 = '" & e.NewValue & "'" And "牌号 = '" & e.NewValue & "'" )
        If dr IsNot Nothing Then
            MessageBox.Show("此货物名称已经存在!")
            e.Cancel = True
        End If
End Select

请老师帮下要怎样写