主题：导入不重复值

Dim Book As New XLS.Book("c:\test\订单.xls")
Dim Sheet As XLS.Sheet = Book.Sheets(0)
Tables("订单").StopRedraw()
Dim nms() As String = {"编号","产品","客户","雇员","单价","折扣","数量","日期"}
For n As Integer = 1 To Sheet.Rows.Count -1
    Dim bh As String = sheet(n,0).Text
    Dim dr As DataRow = DataTables("订单").Find("编号 = '" & bh & "'")
    If dr Is Nothing Then '如果不存在同编号的订单
        dr =  DataTables("订单").AddNew()
    End If
    For m As Integer = 0 To nms.Length - 1
        dr(nms(m)) = Sheet(n,m).Value
    Next
Next
Tables("订单").ResumeRedraw()

请问编号 产品 客户 雇员 四个数值不重复要怎样写，Dim CP As String = sheet(n,0).Text  定义4次吗？

Dim dr As DataRow = DataTables("订单").Find("编号 = '" & bh & CP & KH & CY  & "'")