user3493106 user3493106 - 6 months ago 25
Javascript Question

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

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.AddAt(Int32 index, Control child) +8668018
Telerik.Web.UI.RadAjaxControl.MoveUpdatePanel(Control initiator, Control updated) +133

[HttpException (0x80004005): Please, see whether wrapping the code block, generating the exception, within RadCodeBlock resolves the error.]
Telerik.Web.UI.RadAjaxControl.MoveUpdatePanel(Control initiator, Control updated) +181
Telerik.Web.UI.RadAjaxControl.PerformRender() +375
Telerik.Web.UI.RadAjaxControl.OnPageRender(HtmlTextWriter writer, Control page) +1222
Telerik.Web.UI.RadAjaxControl.RenderPageInAjaxMode(HtmlTextWriter writer, Control page) +95
System.Web.UI.Control.RenderChildrenInternal(HtmlTextWriter writer, ICollection children) +256
System.Web.UI.Control.RenderChildren(HtmlTextWriter writer) +19
System.Web.UI.Page.Render(HtmlTextWriter writer) +29
System.Web.UI.Control.RenderControlInternal(HtmlTextWriter writer, ControlAdapter adapter) +27
System.Web.UI.Control.RenderControl(HtmlTextWriter writer, ControlAdapter adapter) +99
System.Web.UI.Control.RenderControl(HtmlTextWriter writer) +25
System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +1266

Answer

You can also have this problem without using telerik so much better solution is to add an

palceholder instead of RadCodeBlock which will fit for all cases

    <asp:PlaceHolder ID="PlaceHolder1"
your script 

 runat="server"></asp:PlaceHolder>