我试图创建一个简单的用户控件,这是一个滑块。当我添加一个AjaxToolkit SliderExtender到用户控件时,我得到这个(*&$#()@#错误:

Server Error in '/' Application. The Controls collection cannot be modified because the control contains code blocks (i.e. `<% ... %>`). Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.

Exception Details: System.Web.HttpException: The Controls collection cannot be modified because the control contains code blocks (i.e. `<% ... %>`).

Source Error:

An unhandled exception was generated during the execution of the current web request. Information regarding the origin and location of the exception can be identified using the exception stack trace below.

Stack Trace:

[HttpException (0x80004005): The Controls collection cannot be modified because the control contains code blocks (i.e. `<% ... %>`).]    System.Web.UI.ControlCollection.Add(Control child) +8677431    AjaxControlToolkit.ScriptObjectBuilder.RegisterCssReferences(Control control) in d:\E\AjaxTk-AjaxControlToolkit\Release\AjaxControlToolkit\ExtenderBase\ScriptObjectBuilder.cs:293 AjaxControlToolkit.ExtenderControlBase.OnLoad(EventArgs e) in d:\E\AjaxTk-AjaxControlToolkit\Release\AjaxControlToolkit\ExtenderBase\ExtenderControlBase.cs:306 System.Web.UI.Control.LoadRecursive()
+50    System.Web.UI.Control.LoadRecursive()
+141    System.Web.UI.Control.LoadRecursive()
+141    System.Web.UI.Control.LoadRecursive()
+141    System.Web.UI.Control.LoadRecursive()             
+141    System.Web.UI.Control.LoadRecursive()
+141    System.Web.UI.Control.LoadRecursive()
+141    System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +627


Version Information: Microsoft .NET Framework Version:2.0.50727.3074; ASP.NET Version:2.0.50727.3074

我尝试在用户控件中放置一个占位符,并以编程方式将文本框和滑块扩展器添加到占位符,但我仍然得到错误。

下面是简单的代码:

<table cellpadding="0" cellspacing="0" style="width:100%">
    <tbody>
        <tr>
            <td></td>
            <td>
                <asp:Label ID="lblMaxValue" runat="server" Text="Maximum" CssClass="float_right" />
                <asp:Label ID="lblMinValue" runat="server" Text="Minimum" />
            </td>
        </tr>
        <tr>
            <td style="width:60%;">
                <asp:CheckBox ID="chkOn" runat="server" />
                <asp:Label ID="lblPrefix" runat="server" />:&nbsp;
                <asp:Label ID="lblSliderValue" runat="server" />&nbsp;
                <asp:Label ID="lblSuffix" runat="server" />
            </td>
            <td style="text-align:right;width:40%;">                

                    <asp:TextBox ID="txtSlider" runat="server" Text="50" style="display:none;" />
                    <ajaxToolkit:SliderExtender ID="seSlider" runat="server" 
                        BehaviorID="seSlider" 
                        TargetControlID="txtSlider" 
                        BoundControlID="lblSliderValue" 
                        Orientation="Horizontal" 
                        EnableHandleAnimation="true" 
                        Length="200" 
                        Minimum="0" 
                        Maximum="100" 
                        Steps="1" />

            </td>
        </tr>
    </tbody>
</table>

有什么问题吗?


当前回答

我在不同的情况下遇到了同样的问题。 在body标签中有一个简单的元素。 解决方案是:

<asp:PlaceHolder ID="container" runat="server">
    <a id="child" href="<%# variable %>">Change me</a>
</asp:PlaceHolder>
protected new void Page_Load(object sender, EventArgs e)
{    
    Page.Form.DataBind(); // I neded to Call DataBind on Form not on Header
    container.InnerHtml = "Simple text";
}

其他回答

我可以确认将带有<% %>标记的javascript从头部移动到表单标记可以修复此错误

http://italez.wordpress.com/2010/06/22/ajaxcontroltoolkit-calendarextender-e-strana-eccezione/

将java脚本代码保存在body标记中

<body> 
   <script type="text/javascript">
   </script>
</body>

我有这个问题,但不是通过头。我的占位符在身体里。因此,我将所有<%=替换为<%#

protected void Page_Load(object sender, EventArgs e)
{
    Page.Header.DataBind();    
}

这招奏效了。

标签<%= %>不能作为runat="server"的标签。将<%= %>的代码移到runat="server"到另一个标记(body, head,…),或从容器中删除runat="server"。

我尝试使用<%# %>,但没有成功。然后我修改了Page.Header.DataBind();在代码后面this.Header.DataBind();它运行得很好。