我试图创建一个简单的用户控件,它是一个滑块。当我在用户控件中添加 AjaxToolkit 的 SliderExtender 时,我会遇到这个错误:(*&$#()@#)。
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添加占位符,然后以编程方式将文本框和滑块扩展程序添加到占位符中,但仍然出现错误。
以下是简单的代码:
<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" />:
<asp:Label ID="lblSliderValue" runat="server" />
<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>
问题是什么?