主题：如何加载列

        Dim bd1 As New GroupTableBuilder("统计表1",DataTables("成本fa piao录入"))
        Dim dt1 As fxDataSource
        bd1.Groups.AddDef("项目分类")
        bd1.Groups.AddDef("材料供应商")
        bd1.Totals.AddDef("购进金额","已开piao_金额")
        bd1.Totals.AddDef("fa piao数量","已开piao_数量")
        dt1 = bd1.BuildDataSource()
       
        Dim bd2 As New GroupTableBuilder("统计表2",DataTables("付款明细表"))
        Dim dt2  As fxDataSource
        bd2.Groups.AddDef("项目分类")
        bd2.Groups.AddDef("材料供应商")
        bd2.Totals.AddDef("付款金额","已付金额")
        dt2 = bd2.BuildDataSource()
       
        Dim bd3 As New GroupTableBuilder("统计表3",DataTables("材料入库登记"))
        Dim dt3  As fxDataSource
        bd3.Groups.AddDef("项目分类")
        bd3.Groups.AddDef("材料供应商")
        bd3.Totals.AddDef("数量","收料结算_数量")
        bd3.Totals.AddDef("金额","收料结算_金额")
        dt3 = bd3.BuildDataSource()
       
        Dim arr() As String = {"项目分类","材料供应商"}
        dt1.Combine(arr,dt2,arr)
        dt1.Combine(arr,dt3,arr)
       
        dt1.show("统计表") '将统计结果绑定到Table
       
        Dim t As Table = Tables("统计表")
        With t.DataTable.DataCols  '用表达式列计算库存数据
            .Add("按fa piao未付款金额",Gettype(Integer), "IsNull([已开piao_金额],0) - ISNULL([已付金额],0)")
            .Add("未开piao金额",Gettype(Integer), "IsNull([收料结算_金额],0) - ISNULL([已开piao_金额],0)")
            .Add("按收料未付款金额",Gettype(Integer), "IsNull([收料结算_金额],0) - ISNULL([已付金额],0)")
        End With
       
        With Tables("统计表")
            .MergeMode = MergeModeEnum.Standard
            .MergeCols.Clear()
            .MergeCols.Add("项目分类")
            .MergeCols.Add("材料供应商")
            .MergeSort = "项目分类,材料供应商"
            .AllowMerge = True
        End With
       
        Dim g As Subtotalgroup
        t.SubtotalGroups.Clear()
        t.GroupAboveData = False
        t.TreeVisible = False
        t.SpillNode = True
       
        g = New Subtotalgroup
        g.Aggregate = AggregateEnum.Sum
        g.GroupOn = "*"
        g.TotalOn = "收料结算_数量,收料结算_金额,已开piao_金额,已开piao_数量,已付金额,按fa piao未付款金额,按收料未付款金额"
        g.Caption = "总计"
        t.SubtotalGroups.Add(g)
       
        t.Subtotal()
        MainTable = t