The Controls collection cannot be modified because the control contains code blocks (i.e. <% ... %>). Telerik Application

Question

I'm getting this error when I add RadScheduler to my project. I'm using visual studio 2010 and RadControls 2011 q2 Thanks for the help

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) +8828175
   Telerik.Web.SkinRegistrar.RegisterCssReference(Page _page, Control _control, String _url) +486

    [HttpException (0x80004005): Please, see whether wrapping the code block, generating the exception, within RadCodeBlock resolves the error.]
       Telerik.Web.SkinRegistrar.RegisterCssReference(Page _page, Control _control, String _url) +557
       Telerik.Web.SkinRegistrar.RegisterCssReferences(ISkinnableControl _control) +1563
       Telerik.Web.UI.RadDataBoundControl.RegisterCssReferences() +74
       Telerik.Web.UI.RadDataBoundControl.ControlPreRender() +50
       Telerik.Web.UI.RadDataBoundControl.OnPreRender(EventArgs e) +47
       Telerik.Web.UI.RadScheduler.OnPreRender(EventArgs e) +131
       System.Web.UI.Control.PreRenderRecursiveInternal() +103
       System.Web.UI.Control.PreRenderRecursiveInternal() +175
       System.Web.UI.Control.PreRenderRecursiveInternal() +175
       System.Web.UI.Control.PreRenderRecursiveInternal() +175
       System.Web.UI.Control.PreRenderRecursiveInternal() +175
       System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +2496

Answer 1

You cannot modify the control tree when there are <% %> blocks. Check this help topic for additional info.