主题：[求助]表事件运算

Dim dr As DataRow = e.DataRow
Select Case e.DataCol.Name
    Case "重量","单价","折扣"
        If dr.IsNull("重量") Then
            dr("金额") = Nothing
        Else
            dr("金额") = dr("重量") * dr("单价") * dr("折扣")
        End If
End Select

If e.DataCol.Name = "货物名称" Then 
    If e.NewValue Is Nothing Then  
        e.DataRow("单价2") = Nothing
    Else
        Dim fdr As DataRow
        fdr = DataTables("货物名称").Find("[货物名称] = '" & e.NewValue & "'")
        If fdr IsNot Nothing Then
            e.DataRow("单价2") = fdr("单价2")
        End If
    End If
End If
If e.DataCol.Name = "公司名称" Then 
    If e.NewValue Is Nothing Then
        e.DataRow("起运地") = Nothing
        e.DataRow("仓库") = Nothing
        e.DataRow("折扣") = Nothing 
    Else
        Dim fdr As DataRow
        fdr = DataTables("客户").Find("[公司名称] = '" & e.NewValue & "'")
        If fdr IsNot Nothing Then 
            e.DataRow("起运地") = fdr("起运地")
            e.DataRow("仓库") = fdr("仓库")
            e.DataRow("折扣") = fdr("折扣")
        End If
    End If
End If