Multiple controls with the same ID 'ctl34' were found.

[Andrew Lawrence]

Hi,
I have just tried upgrading Telerik RadControls for ASP .NET AJAX from 2008.3.1314 to 2010.1.519.

The upgrade appeared to go OK locally but once I deployed live I started getting the following exception thrown intermittently upon a loading a page:
System.Web.HttpException: Multiple controls with the same ID 'ctl34' were found. FindControl requires that controls have unique IDs.
at System.Web.UI.Control.FillNamedControlsTable(Control namingContainer, ControlCollection controls)
at System.Web.UI.Control.FillNamedControlsTable(Control namingContainer, ControlCollection controls)
at System.Web.UI.Control.EnsureNamedControlsTable()
at System.Web.UI.Control.FindControl(String id, Int32 pathOffset)
at System.Web.UI.Control.FindControl(String id, Int32 pathOffset)
at System.Web.UI.Control.FindControl(String id)
at Telerik.Web.ChildControlHelper.FindControlRecursive(Control searcher, String ID)
at Telerik.Web.UI.RadAjaxControl.PerformRender()
at Telerik.Web.UI.RadAjaxControl.OnPageRender(HtmlTextWriter writer, Control page)
at Telerik.Web.UI.RadAjaxControl.RenderPageInAjaxMode(HtmlTextWriter writer, Control page)
at System.Web.UI.Control.RenderChildrenInternal(HtmlTextWriter writer, ICollection children)
at System.Web.UI.Control.RenderChildren(HtmlTextWriter writer)
at System.Web.UI.Page.Render(HtmlTextWriter writer)
at umbraco.UmbracoDefault.Render(HtmlTextWriter output)
at System.Web.UI.Adapters.ControlAdapter.Render(HtmlTextWriter writer)
at System.Web.UI.Control.RenderControlInternal(HtmlTextWriter writer, ControlAdapter adapter)
at System.Web.UI.Control.RenderControl(HtmlTextWriter writer, ControlAdapter adapter)
at System.Web.UI.Control.RenderControl(HtmlTextWriter writer)
at System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint)


I have not made any changes to the page, and the error seems to be coming from inside RadAjax, so the culprit is definitely something going wrong within RadAjax.

On the page I have some RadAjax, a RadComboBox and a RadMaskedTextBox. I am also using PeterBlum 4.0.5 validators.

I think I remember getting this problem before with older versions of Telerik but I believe it disappeared with one of the upgrades, so this appears to be a regression.

[Iana Tsolova]

Hi Andrew,

Could you please confirm that the error does not persist if you disable ajax?
However I would suggest that you open a formal support ticket and send us a runnable sample or at least the problematic page.

Greetings,
Iana
the Telerik team

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