动态创建 rbl 时，单选按钮列表结果不起作用

Question

我有 20 个动态创建的单选按钮列表 - 然后在提交表单时声明。

我还有一些代码，用于计算已回答问题的数量和已回答问题的总价值。 - 当单选按钮列表被硬编码到页面中时，此代码曾经可以工作，但现在不行了。 - 我正在将已回答的问题数和所有答案的总价值写入页面，但它们返回为 0。

有人能明白为什么现在单选按钮列表是动态创建的，这可能不起作用。？

背后代码：

Sub Page_Load(ByVal Sender as Object, ByVal E as EventArgs)

        For i As Integer = 1 To 20

            Dim TableRow As New TableRow()
            Dim TableRowCell_1 As New TableCell()
            TableRow.Cells.Add(TableRowCell_1)
            holidayQuestionnaireTable.Rows.Add(TableRow)

            Dim question As New RadioButtonList
            question.ID = "question" & i

            question.Items.Insert(0, new listitem("", "1"))
            question.Items.Insert(1, new listitem("", "2"))
            TableRowCell_1.Controls.Add(question)

        Next

End Sub

...

Sub btnSendFeedback_Click(sender as Object, e as EventArgs)

    Dim question1 As RadioButtonList = DirectCast(Page.FindControl("question1"), RadioButtonList)
    Dim question2 As RadioButtonList = DirectCast(Page.FindControl("question2"), RadioButtonList)
    Dim question3 ...
    ...
    Dim question19 As RadioButtonList = DirectCast(Page.FindControl("question19"), RadioButtonList)
    Dim question20 As RadioButtonList = DirectCast(Page.FindControl("question20"), RadioButtonList)

    Dim rblCount As Double
    Dim total As Double
    Dim avg As Double

    For Each ctrl As UI.Control In Me.myPanel.Controls
        If TypeOf ctrl Is RadioButtonList Then
            Dim rbl As RadioButtonList = DirectCast(ctrl, RadioButtonList)
            If rbl.SelectedIndex > -1 And not rbl.ID = "question18" Then
                Dim value As Double = Double.Parse(rbl.SelectedValue)
                total += value
                rblCount += 1
            End If
        End If
    Next

    Response.Write(rblCount & " - " & total & " - " & (total / rblCount))

End Sub

正文：

<asp:Placeholder ID="myPanel" runat="server">
        <asp:Table runat="server" CellPadding="0" CellSpacing="0" GridLines="None" HorizontalAlign="Center" CssClass="ratingtable" ID="holidayQuestionnaireTable" />
        <asp:Button OnClick="btnSendFeedback_Click" runat="server" Text="Submit..." ID="submitbutton" />
</asp:Placeholder>

Answer 1

您已更改面板的内容并添加了一个表格，而不是使用面板直接添加RadioButtonLists。 FindControl 将仅查找面板的 NamingContainer，而不查找其子控件的 NamingContainer。搜索面板的控制集合也不起作用，因为 RBL 位于面板内的表内。因此，您必须循环 TableRows 才能获取 RBL。看一下：

For Each row As TableRow In Me.holidayQuestionnaireTable.Rows
     For Each cell As TableCell In row.Cells
         For Each ctrl As Control In cell.Controls
             If TypeOf ctrl Is RadioButtonList Then
                Dim rbl As RadioButtonList = DirectCast(ctrl, RadioButtonList)
                If rbl.SelectedIndex <> -1 AndAlso rbl.ID <> "question18" Then
                   Dim value As Int32 = Int32.Parse(rbl.SelectedValue)
                   total += value
                   rblCount += 1 'count only the selected RadiobuttonLists'
                End If
             End If
         Next
    Next
Next

如果您想使用 FindControl 方法，则必须使用每个 radioButtonList 的 NamingContainer，即 TableRow。所以这也可以工作，但是非常静态并且容易出错：

Dim question1 As RadioButtonList = DirectCast(Me.holidayQuestionnaireTable.Rows(0).FindControl("question1"), RadioButtonList)
Dim question2 As RadioButtonList = DirectCast(Me.holidayQuestionnaireTable.Rows(1).FindControl("question2"), RadioButtonList)
Dim question3 As RadioButtonList = DirectCast(Me.holidayQuestionnaireTable.Rows(2).FindControl("question3"), RadioButtonList)