Question

我有一个数据表，并按特定顺序填充了数据。将数据放入表格后，我需要对其他字段进行一些计算，但是如果有意义的话，我需要从底部开始进行计算？

此刻我提出以下内容：

For Each dr As DataRow In Me.DataSet1.MyDataTable()

        Dim parent_warehouse As String = dr("WH")
        Dim parent_product As String = dr("ProductCode")
        Dim new_material = 0
        Dim new_labour = 0
        Dim new_overhead = 0
        Dim new_outwork = 0
        Dim new_total = 0

        If isassembly(parent_warehouse, parent_product) Then
            If Not IsDBNull(dr("assy")) Then

                For Each dr1 As DataRow In Me.DataSet1.MyDataTable()
                    Dim assy = dr("assy")
                    If assy = parent_warehouse + parent_product Then
                        new_material = new_material + (dr1("material") * (dr1("UsageQuantity") / dr1("Wastage")))
                        new_labour = new_labour + (dr1("labour") * dr1("UsageQuantity"))
                        new_overhead = new_overhead + (dr1("overhead") * dr1("UsageQuantity"))
                        new_outwork = new_outwork + (dr1("outwork") * dr1("UsageQuantity"))
                        new_total = new_material + new_labour + new_overhead + new_outwork
                    End If
                Next
                dr("new_material") = new_material
                dr("new_labour") = new_labour
                dr("new_overhead") = new_overhead
                dr("new_outwork") = new_outwork
                dr("new_total") = new_total
            Else
                GoTo skip
            End If
        Else
            dr("new_material") = dr("material")
            dr("new_labour") = dr("labour")
            dr("new_overhead") = dr("overhead")
            dr("new_outwork") = dr("outwork")
            dr("new_total") = dr("total")
        End If
skip:
    Next

我目前遇到的问题是，当它遍历记录时，它会从上到下遍历它们，我希望它从下而上遍历，因为成本应该从底层产品开始累积，因此他们的父产品会获得新的成本，并一直保持最高价格。

Answer 1

向后循环将是您的最佳选择。您将使用带有' declare a variable for our DataTable Dim dt As DataTable = Me.DataSet1.MyDataTable() ' we're setting our 'i' variable to the last row (account for 0-index) ' in a typical For Loop, the Step is +1, but we're specifying -1 to go backwards For i as Integer = dt.Rows.Count - 1 to 0 Step -1 ' execute logic ' something like CDec(dt.Rows(i).Item("DecimalColumn")) to convert decimal type ' CInt(), CStr(), CDate() are also very useful, Integer, String, and Date respectively Next

的For循环

jQuery( '.add_to_cart_button' ).on( 'click', function($) {
  $( 'body' ).trigger( 'update_checkout' );
});

Answer 2

我认为您需要对表的默认视图进行排序，然后遍历默认视图。

Me.DataSet1.MyDataTable.defaultview.sort = "material", "labor" 'etc.

For Each dr As DataRowView In Me.DataSet1.MyDataTable.defaultview
'...

*根据@jmcilhinney评论中的更正进行编辑。 -谢谢！

VB.net以特定顺序遍历记录

2 个答案: