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

试着写你的java脚本代码以外的头标签,它肯定会工作。当我复制并粘贴我的Java脚本代码到页面底部时,它就解决了。在以前它放在HEAD标签,现在只是在关闭表单标签之前。

    </div>
        <script>
                    function validate() {
                        try {

                        var username = document.getElementById("<%=txtUserName.ClientID%>").value;
                        var password = document.getElementById("<%=txtPWD.ClientID%>").value;

                            if (username == "" && password == "")
                                alert("Enter Username and Passowrd");
                            else {
                                if (username == "")
                                    alert("Enter Username");
                                else if (password == "")
                                    alert("Enter Password");
                            }

                        }

                    catch (err) {
                    }
                }
                </script>
</form>

其他回答

将JavaScript放在div标签下。

<div runat="server"> //div tag must have runat server
  //Your JavaScript code goes here....
</div>

它会工作! !

“<%#”数据绑定技术不会直接在<head>标签中的<link>标签内工作:

<head runat="server">

  <link rel="stylesheet" type="text/css" 
        href="css/style.css?v=<%# My.Constants.CSS_VERSION %>" />

</head>

上面的代码将计算为

<head>

  <link rel="stylesheet" type="text/css" 
        href="css/style.css?v=&lt;%# My.Constants.CSS_VERSION %>" />

</head>

相反,你应该做以下事情(注意里面的两个双引号):

<head runat="server">

  <link rel="stylesheet" type="text/css" 
        href="css/style.css?v=<%# "" + My.Constants.CSS_VERSION %>" />

</head>

你会得到你想要的结果:

<head>

  <link rel="stylesheet" type="text/css" href="css/style.css?v=1.5" />

</head>

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。

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"。

我解决了一个类似的错误,把<script>内容占位符内的<head>,而不是把<script>之外的内容占位符内的<head>