在 ControlParameter 中找不到控件

Question

我的页面有一个详细信息视图，其中有一个隐藏字段，该字段由 SQLDataSource 引用以填充同一详细信息视图中的不同字段。无论我尝试多少种不同的方法，我都无法通过代码隐藏来找到控件。我确实需要能够显示与 dsPicklist SqlDataSource 关联的 TEXT 字段。我已经标记了导致问题的代码。我真的很感谢在尝试显示此信息时提供一些帮助。

<asp:Label ID="Label1" runat="server" Text="Select Survey:"></asp:Label>

<asp:DropDownList ID="DropDownList1" runat="server" AutoPostBack="True"
    DataSourceID="dsSurvey" DataTextField="SurveyName" DataValueField="SurveyID">
</asp:DropDownList>

<asp:DetailsView ID="dvSurveyQuestions" runat="server" AllowPaging="True" 
AutoGenerateRows="False" CellPadding="4" DataKeyNames="QuestionID" 
DataSourceID="dsSurveyQuestions" ForeColor="#333333" GridLines="None" Height="50px" 
Width="100%">
<Fields>
    <asp:BoundField DataField="QuestionNum" HeaderText="Question Number" 
        SortExpression="QuestionNum" />

    **<asp:TemplateField>
        <ItemTemplate>
            <asp:HiddenField ID="hiddenQuestionID" runat="server" 
            Value='<%# Bind("QuestionID") %>'>
            </asp:HiddenField>
        </ItemTemplate>
    </asp:TemplateField>**

    <asp:TemplateField HeaderText="Question Type" SortExpression="QType">
        <EditItemTemplate>
            <asp:DropDownList ID="DropDownList4" runat="server" 
                SelectedValue='<%# Bind("QType") %>'>
                <asp:ListItem Value="Picklist">Picklist</asp:ListItem>
                <asp:ListItem Value="Text">Text</asp:ListItem>
            </asp:DropDownList>
        </EditItemTemplate>
        <InsertItemTemplate>
            <asp:DropDownList ID="DropDownList5" runat="server" 
                SelectedValue='<%# Bind("QType") %>'>
                <asp:ListItem Value="Picklist">Picklist</asp:ListItem>
                <asp:ListItem Value="Text">Text</asp:ListItem>
            </asp:DropDownList>
        </InsertItemTemplate>
        <ItemTemplate>
            <asp:Label ID="lblQType" runat="server" Text='<%# Bind("QType") %>'>
            </asp:Label>
        </ItemTemplate>
    </asp:TemplateField>

    <asp:TemplateField HeaderText="Question" SortExpression="Question">
        <EditItemTemplate>
            <asp:TextBox ID="TextBox1" runat="server" TextMode="MultiLine" 
            Text='<%# Bind("Question") %>'>
            </asp:TextBox>
        </EditItemTemplate>
        <InsertItemTemplate>
            <asp:TextBox ID="TextBox1" runat="server" TextMode="MultiLine" 
            Text='<%# Bind("Question") %>'>
            </asp:TextBox>
        </InsertItemTemplate>
        <ItemTemplate>
            <asp:Label ID="lblQuestion" runat="server" Text='<%# Bind("Question") %>'>    
            </asp:Label>
        </ItemTemplate>
    </asp:TemplateField>

    <asp:TemplateField HeaderText="Answer" SortExpression="PicklistID">
        <EditItemTemplate>
        <!-- put something here after ItemTemplate testing -->
        </EditItemTemplate>
        <InsertItemTemplate>
        <!-- put something here after ItemTemplate testing -->
        </InsertItemTemplate>
        <ItemTemplate>
            <asp:HiddenField ID="hiddenPicklistID" runat="server"  
            Value='<%# Bind("PicklistID") %>' />
            <asp:BulletedList ID="blText" runat="server" DataSourceID="dsPicklist" 
            DataTextField="TEXT">
            </asp:BulletedList>
        </ItemTemplate>
    </asp:TemplateField>

    <asp:TemplateField HeaderText="Answer Type" SortExpression="AnswerType">
        <EditItemTemplate>
            <asp:DropDownList ID="DropDownList2" runat="server" 
                SelectedValue='<%# Bind("AnswerType") %>'>
                <asp:ListItem Value="S">Single Choice (radio button)</asp:ListItem>
                <asp:ListItem Value="M">Multiple Choices (checkboxes)</asp:ListItem>
                <asp:ListItem Value="T">Text (textbox)</asp:ListItem>
            </asp:DropDownList>
        </EditItemTemplate>
        <InsertItemTemplate>
            <asp:DropDownList ID="DropDownList3" runat="server" 
                SelectedValue='<%# Bind("AnswerType") %>'>
                <asp:ListItem Value="S">Single Choice (radio button)</asp:ListItem>
                <asp:ListItem Value="M">Multiple Choices (checkboxes)</asp:ListItem>
                <asp:ListItem Value="T">Text (textbox)</asp:ListItem>
            </asp:DropDownList>
        </InsertItemTemplate>
        <ItemTemplate>
            <asp:Label ID="lblAnswerType" runat="server" Text='<%# Bind("AnswerType") %>'></asp:Label>
        </ItemTemplate>
    </asp:TemplateField>

    <asp:BoundField DataField="Subsequence" HeaderText="Subsequence" 
        SortExpression="Subsequence" />
    <asp:CheckBoxField DataField="Active" HeaderText="Active" 
            SortExpression="Active" />
    <asp:CheckBoxField DataField="Question_Locked" HeaderText="Question Locked" 
            SortExpression="Question_Locked" />
    <asp:BoundField DataField="QHelp" HeaderText="Question Help" SortExpression="QHelp" />
    <asp:BoundField DataField="Script" HeaderText="Script" 
        SortExpression="Script" />
    <asp:CommandField ShowDeleteButton="True" ShowEditButton="True" 
        ShowInsertButton="True" />
    </Fields>
</asp:DetailsView>
<asp:SqlDataSource ID="dsPicklist" runat="server" 
    ConnectionString="<%$ ConnectionStrings:SurveyConnectionString %>" 
    SelectCommand="SELECT p.TEXT 
                   FROM PICKLIST p 
                   JOIN C_Survey_Questions c 
                   ON p.PICKLISTID = c.PicklistID 
                   AND c.QuestionID = @QuestionID 
                   AND c.SurveyID = @SurveyID 
                   WHERE p.PICKLISTID IS NOT NULL 
                   AND c.PicklistID IS NOT NULL">
    <SelectParameters>
        <asp:ControlParameter ControlID="DropDownList1" Name="SurveyID" 
            PropertyName="SelectedValue" Type="Int32" />
        **<asp:ControlParameter ControlID="hiddenQuestionID" Name="QuestionID" 
            PropertyName="SelectedValue" Type="Int32" />**
    </SelectParameters>
</asp:SqlDataSource>

<asp:SqlDataSource ID="dsSurvey" runat="server" 
    ConnectionString="<%$ ConnectionStrings:SurveyConnectionString %>" 
    SelectCommand="SELECT [SurveyID], [SurveyName] 
                   FROM [C_Survey] 
                   ORDER BY [SurveyName]">
</asp:SqlDataSource>

<asp:SqlDataSource ID="dsSurveyQuestions" runat="server" 
    ConnectionString="<%$ ConnectionStrings:SurveyConnectionString %>" 
    DeleteCommand="DELETE FROM [C_Survey_Questions] WHERE [QuestionID] = @QuestionID" 
    InsertCommand="INSERT INTO [C_Survey_Questions] ([SurveyID], [Question], [QType],
                   [PickListID], [QuestionNum], [Subsequence], [Active], [Script], 
                   [Question_Locked], [QHelp], [Createdate], [Modifydate],
                   [AnswerType]) 
                   VALUES (@SurveyID, @Question, @QType, @PickListID, @QuestionNum, 
                   @Subsequence, @Active, @Script, @Question_Locked, @QHelp, getdate(), 
                   getdate(), @AnswerType)" 
    SelectCommand="SELECT * FROM C_Survey_Questions WHERE SurveyID = @SurveyID" 
    UpdateCommand="UPDATE [C_Survey_Questions] 
                   SET [SurveyID] = @SurveyID, [Question] = @Question,
                   [QType] = @QType, [PickListID] = @PickListID, 
                   [QuestionNum] = @QuestionNum, [Subsequence] = @Subsequence, 
                   [Active] = @Active, [Script] = @Script, 
                   [Question_Locked] = @Question_Locked, 
                   [QHelp] = @QHelp, [Modifydate] = getdate(), 
                   [AnswerType] = @AnswerType WHERE [QuestionID] = @QuestionID">
    <DeleteParameters>
        <asp:Parameter Name="QuestionID" Type="Int32" />
    </DeleteParameters>
    <InsertParameters>
        <asp:Parameter Name="SurveyID" Type="Int32" />
        <asp:Parameter Name="Question" Type="String" />
        <asp:Parameter Name="QType" Type="String" />
        <asp:Parameter Name="PickListID" Type="String" />
        <asp:Parameter Name="QuestionNum" Type="Int32" />
        <asp:Parameter Name="Subsequence" Type="Int32" />
        <asp:Parameter Name="Active" Type="Boolean" />
        <asp:Parameter Name="Script" Type="String" />
        <asp:Parameter Name="Question_Locked" Type="Boolean" />
        <asp:Parameter Name="QHelp" Type="String" />
        <asp:Parameter Name="Createdate" Type="DateTime" />
        <asp:Parameter Name="Modifydate" Type="DateTime" />
        <asp:Parameter Name="AnswerType" Type="String" />
    </InsertParameters>
    <SelectParameters>
        <asp:ControlParameter ControlID="DropDownList1" Name="SurveyID" 
            PropertyName="SelectedValue" Type="Int32" />
    </SelectParameters>
    <UpdateParameters>
        <asp:Parameter Name="SurveyID" Type="Int32" />
        <asp:Parameter Name="Question" Type="String" />
        <asp:Parameter Name="QType" Type="String" />
        <asp:Parameter Name="PickListID" Type="String" />
        <asp:Parameter Name="QuestionNum" Type="Int32" />
        <asp:Parameter Name="Subsequence" Type="Int32" />
        <asp:Parameter Name="Active" Type="Boolean" />
        <asp:Parameter Name="Script" Type="String" />
        <asp:Parameter Name="Question_Locked" Type="Boolean" />
        <asp:Parameter Name="QHelp" Type="String" />
        <asp:Parameter Name="Modifydate" Type="DateTime" />
        <asp:Parameter Name="AnswerType" Type="String" />
    </UpdateParameters>
</asp:SqlDataSource>




Protected Sub dvSurveyQuestions_ItemInserting(ByVal sender As Object, ByVal e As System.Web.UI.WebControls.DetailsViewInsertEventArgs) Handles dvSurveyQuestions.ItemInserting
    'The DetailsView does not include SurveyID column...we need to set this column during INSERT operations because each question must belong to some survey.
    e.Values("SurveyID") = DropDownList1.SelectedValue
End Sub
Protected Sub dvSurveyQuestions_ItemUpdating(ByVal sender As Object, ByVal e As System.Web.UI.WebControls.DetailsViewUpdateEventArgs) Handles dvSurveyQuestions.ItemUpdating
    'The DetailsView does not include SurveyID column...we need to set this column during UPDATE operations because each question must belong to some survey.
    e.NewValues("SurveyID") = DropDownList1.SelectedValue
End Sub
Protected Sub dvSurveyQuestions_DataBound(ByVal sender As Object, ByVal e As System.EventArgs) Handles dvSurveyQuestions.DataBound
    'The event handler checks the row count of the DetailsView control. If it is zero then the mode of the DetailsView is changed to Insert using ChangeMode() method.
    If dvSurveyQuestions.Rows.Count = 0 Then
        dvSurveyQuestions.ChangeMode(DetailsViewMode.Insert)
    End If
    If dvSurveyQuestions.CurrentMode = DetailsViewMode.[ReadOnly] Then
        Dim txtName As TextBox = DirectCast(Page.Form.FindControl("dvSurveyQuestions:hiddenQuestionID"), TextBox)
    End If
End Sub
End Class

Answer 1

我发现此链接有助于在没有服务器端的情况下解决问题： 解决错误“无法” find control 'xxx' in ControlParameter 'xxx'."

作者说可以使用美元字符（$）来访问内部控件。

例如：

dvSurveyQuestions$hiddenQuestionID

将获取hiddenQuestionID的值，它是dvSurveyQuestions的内部控件

Answer 2

试试这个：

Dim txtName = DirectCast(dvSurveyQuestions.FindControl("hiddenQuestionID"), TextBox) 

因为 TextBox 的 NamingContainer 是 DetailsView 而不是 Page。