主题：求一代码连接

三个表，{入库}{出库}{库存表}

{库存表}DataColChanged事件本来有这个代码

Dim dr As DataRow = e.DataRow
Dim dt1 As DataTable = DataTables("入库")
Dim dt2 As DataTable = DataTables("出库")
If e.DataCol.Name = "序号" Then
    dr("入库数量") = dt1.Compute("Sum(入库数量)","[序号] = '" & dr("序号") & "'")
    dr("入库额") = dt1.Compute("Sum(入库额)","[序号] = '" & dr("序号") & "'")
    dr("出库数量") = dt2.Compute("Sum(出库数量)","[序号] = '" & dr("序号") & "'")
    dr("出库额") = dt2.Compute("Sum(出库额)","[序号] = '" & dr("序号") & "'")
End If

在{库存表}里如何加上下面的代码

Select Case e.DataCol.Name
Case "入库数量","出库数量"
For Each dr As DataRow In e.DataTable.Select("[_SortKey] >= " & e.DataRow("_SortKey"))
Dim Val1 As Double = e.DataTable.Compute("Sum(入库数量)","[_SortKey] <= " & dr("_SortKey"))
Dim Val2 As Double = e.DataTable.Compute("Sum(出库数量)","[_SortKey] <= " & dr("_SortKey"))
dr("库存量") = Val1 - Val2
Next
End Select

还有小小问题，没入库的也自动计算了

刷新一下