Question

我在DataGrid中对列的值求和，每次更新另一个DataGrid时都会更新该列。比如说，用户在DataGrid1中选择值，它将该数据添加到DataGrid。那部分工作非常好。我需要对其中一个列进行求和，这样它就能给我一个总和。这是我提出的代码，它在GridView1.SelectedIndexChanged事件下触发。

        For Each GridViewRow In GridView2.Rows


            Sum = Convert.ToDouble(row.Cells(3).Text)
            Total = Sum + Total
            lblTotal.Text = Total.ToString

        Next

现在问题来自于此。如果我有两个值，比如... 2.00，总和就可以了。它会给我4.但如果我添加另一个项目，比如说Item2，它的值为2.30，它总共给我4.60。如果我先添加2.30项，然后添加2项，它会给我一个值4.发生了什么，这样一个简单的数学怎么会出错：P！我错过了什么吗？四舍五入？需要解析什么？

提前完整代码

 Protected Sub GridView1_SelectedIndexChanged(sender As Object, e As EventArgs) Handles GridView1.SelectedIndexChanged


    Dim row = GridView1.SelectedRow
    If Not row Is Nothing AndAlso IsNumeric(row.Cells(3).Text) Then
        Dim Price As Double = CDbl(row.Cells(3).Text)
        Dim Name As String = CStr(row.Cells(2).Text)
        lblCart.Visible = True
        Dim InfoTotal As String = "$" & "    " & Precio & "      " & Nombre


        Dim Total As Double

        If GridView2.Rows.Count = 0 Then
            '  dt = New DataTable()
            dt.Columns.Add(New DataColumn("Name", GetType(System.String)))
            dt.Columns.Add(New DataColumn("Price", GetType(System.String)))
        Else
            dt = DirectCast(Session("DataTable"), DataTable)
        End If

        Dim Sum As Double
        Dim dr1 As DataRow = dt.NewRow()
        dr1(0) = Name.ToString
        dr1(1) = CDbl(Price.ToString)
        dt.Rows.Add(dr1)
        GridView2.DataSource = dt
        GridView2.DataBind()
        Session("DataTable") = dt

        For Each GridViewRow In GridView2.Rows
            Sum = CDbl(row.Cells(3).Text)
            Total += Sum
        Next

        lblTotal.Text = Total.ToString
        ListBox1.Items.Add(CStr(InfoTotal))

    End If


End Sub

Answer 1

听起来你错过了一些额外的代码，你在那里添加两次值 - 请发布你的完整代码。下面的代码完成了你正在做的事情（从而稍微减少） - 同样，在for完成之前，没有必要更新标签。

For Each GridViewRow In GridView2.Rows
                Sum = CDbl(row.Cells(3).Text)
                Total += Sum
            Next

lblTotal.Text = Total.ToString

Answer 2

代码很好......这很简单。我添加了一个会话并将Rows更改为Column。该领域的代码：

 Dim Total As Double
    Dim Sum As Double
    Total = Session("Total")



    For Each GridViewRow In GridView2.Columns

        Sum = CDbl(row.Cells(3).Text)
        Total = CDbl(Total + Sum)
        Session("Total") = Total

    Next

    lblTotal.Text = Total.ToString

DataGrid不正确地汇总值

2 个答案: