主题：出库数量大于库存是禁止操作

出库本datacolchanging事件

If e.DataCol.Name.StartsWith("尺码_") Then
    Dim sum1 As Double = DataTables("入库表").compute("sum(" & e.DataCol.name & ")", "款号='" & e.DataRow("款号") & "'")
    Dim sum2 As Double = DataTables("出库表").compute("sum(" & e.DataCol.name & ")", "款号='" & e.DataRow("款号") & "'")
    If sum2-e.OldValue+e.NewValue > sum1 Then
        msgbox("库存不够")
        e.cancel = True
    End If
End If