专家坐堂-关于取值的代码Foxtable(狐表) - 新一代数据库软件，完美融合Access、Foxpro、Excel、vb.net之优势，人人都能掌握的快速软件开发工具!

Dim aa As Integer = CurrentTable.Position

Dim bb As String = Tables("原材料出库表").Rows(aa)("物料名称")

Dim cc As String = Tables("原材料出库表").Rows(aa)("领用日期")

output.show(bb)

output.show(cc)

Dim sum1 As Double = DataTables("原材料入库表").Compute("Sum(数量)", "物料名称 = \'"& bb &"\' and 日期 <= #"& cc &"# ")

Dim sum2 As Double = DataTables("原材料入库表").Compute("Sum(金额)", "物料名称 = \'"& bb &"\' and 日期 <= #"& cc &"# ")

output.show(sum1)

output.show(sum2)

Dim sum3 As Double = sum2 / sum1

output.show(sum3)

结果：

烧饼

2017-10-15

2.7

放到表事件后，计算的条件表达式里的bb和cc改成了新值zf1 和zf2后的代码：

Dim co1 As DataCol = e.DataCol

Dim dr As DataRow = e.DataRow

Select Case co1.Name

Case "领用日期","物料代码"

If dr.IsNull("物料代码") OrElse dr.IsNull("领用日期") Then \'如果数量或单价为空

dr("数量") = Nothing

dr("单价") = Nothing

dr("金额") = Nothing

Else

Dim zf1 As String = e.NewValue

Dim zf2 As String = e.NewValue

zf1 = dr("物料代码")

zf2 = dr("领用日期")

Dim sum1 As Double = DataTables("原材料入库表").Compute("Sum(数量)", "物料名称 = \'"& zf1 &"\' and 日期 <= #"& zf2 &"# ")

Dim sum2 As Double = DataTables("原材料入库表").Compute("Sum(金额)", "物料名称 = \'"& zf1 &"\' and 日期 <= #"& zf2 &"# ")

Messagebox.Show(sum1)

Messagebox.Show(sum2)

Dim sum3 As Double = sum2 / sum1

dr("单价") = sum3

Messagebox.Show(sum3)

End If

End Select

运行后sum1和sum2没计算出结果，全是0。

请老师给看下这段代码吧，谢谢！！！！