Page had an existing working RadGrid control.
Issue started after I dragged a NEW radgrid control onto the page.
Script Error:
Runtime: Error:
Script control 'gdtcSharedCalendar' is not a registered script control. Script controls must be registered using RegisterScriptControl() before calling RegisterScriptDescriptors().
Parameter name: scriptControl
Warning shown in Visual Studio.
c:\tfs\Test\FirmDB\FirmDB.Web\MasterPages\Main.Master: ASP.NET runtime error: Reference assemblies for target .NET Framework version not found; please ensure they are installed, or select a valid target version.
Any suggestions?
Thanks,
Rog
1 Answer, 1 is accepted
Hi Rog,
Based on your description, the error "Script control 'gdtcSharedCalendar' is not a registered script control" and the Visual Studio warning about missing reference assemblies indicate two separate but potentially related issues that appeared after dragging the new RadGrid onto the page.
The ID gdtcSharedCalendar is the shared RadCalendar instance auto-created by GridDateTimeColumn for its filter/edit popup, so the error almost always points to a ScriptManager registration problem on the page rather than to the grid itself.
Troubleshooting Steps
Only one ScriptManager / RadScriptManager per page
- When you drag a control from the Toolbox onto a content page that already lives inside a MasterPage, Visual Studio frequently inserts a second
<asp:ScriptManager>(or<telerik:RadScriptManager>) — even though one already exists on the Master. ASP.NET allows only one per page. - Open the content page in Source view and remove any newly added ScriptManager. If you need to add scripts/services from the content page, use a
<asp:ScriptManagerProxy>instead. - The ScriptManager must be inside the
<form>tag and outside anyUpdatePanel.
- When you drag a control from the Toolbox onto a content page that already lives inside a MasterPage, Visual Studio frequently inserts a second
Control placement
- All Telerik controls, including RadGrid and the auto-created calendars, must be within the
<form>element — not in the<head>or outside the form.
- All Telerik controls, including RadGrid and the auto-created calendars, must be within the
RegisterWithScriptManager property
- If you have set
RegisterWithScriptManager="false"on any Telerik control, you must manually register all required scripts and styles. For most scenarios keep it set totrue.
- If you have set
Check for duplicate IDs or conflicts
- Adding a new RadGrid may introduce duplicate control IDs or conflicting script registrations. Make sure every control on the page has a unique
ID.
- Adding a new RadGrid may introduce duplicate control IDs or conflicting script registrations. Make sure every control on the page has a unique
Check web.config for duplicated entries
- The designer can re-add entries under
<system.web>/<httpHandlers>,<system.webServer>/<handlers>,<pages>/<controls>, or<assemblies>. Remove duplicates so the same handler/tag prefix is not registered twice.
- The designer can re-add entries under
Verify a single Telerik.Web.UI.dll version
- Make sure the
Telerik.Web.UI.dllreferenced by the content page matches the version used on the Master Page. Mismatched versions can also causeRegisterScriptControlfailures.
- Make sure the
Project target framework (the VS warning)
- The warning "Reference assemblies for target .NET Framework version not found" means Visual Studio cannot find the targeting pack for the .NET Framework version your project targets. It is unrelated to Telerik but can mask real compile errors and produce odd designer/runtime behaviour.
- Right-click the web project → Properties → check the Target Framework.
- Install the matching .NET Framework Developer Pack from https://dotnet.microsoft.com/download/dotnet-framework (e.g., 4.6.2, 4.7.2, or 4.8), or add it via the Visual Studio Installer → Modify → Individual components → ".NET Framework 4.x targeting pack".
- For Telerik UI for ASP.NET AJAX, the project should target .NET Framework 4.5 or later.
Clean and rebuild
- Clean the solution, delete the
bin\andobj\folders, and clear the ASP.NET temporary files in:%LOCALAPPDATA%\Temp\Temporary ASP.NET Files%WINDIR%\Microsoft.NET\Framework[64]\<ver>\Temporary ASP.NET Files
- Then rebuild. Stale cached scripts are a common cause of "not a registered script control" after toolbox edits.
- Clean the solution, delete the
Recommended Order
Fix the targeting pack first so the build is trustworthy, then remove the duplicate ScriptManager that Visual Studio injected when you dropped the second RadGrid, clean up any duplicated web.config entries, and finally clean/rebuild. This combination resolves the gdtcSharedCalendar registration error in the vast majority of reported cases.
Additional Information Needed
If the issue persists after the steps above, please share:
- Your aspx, usercontrol and masterpage along with any codebehind files
- The exact markup of your
RadScriptManager/ScriptManagerand bothRadGridcontrols. - Details about any
UpdatePanelusage on the page or master. - The Telerik UI for ASP.NET AJAX version you are using.
- The full error stack trace, if available.
Summary
The gdtcSharedCalendar error is almost certainly caused by a duplicate ScriptManager or duplicated web.config registrations introduced when the new RadGrid was dragged onto the page, while the framework warning is a separate environment issue fixed by installing the correct .NET Framework Developer Pack. Addressing both should restore the page to a working state.
Regards,
Rumen
Progress Telerik