
I put the ScriptManager in a Master Page now when I open any other aspx page I get the following
[A]Telerik.Web.UI.RadScriptManager cannot be cast to [B] Telerik.Web.UI.RadScriptManager. Type A originates from Telerik.Web.UI, Version 2010.1.309.20, .....at location <local machine path>\Project Assemblies\venh7src01\Telerik.Web.UI.dll. Type B originates from Telerik.Web.UI, Version 2010.1.309.35, .....at location <local machine path>\Project Assemblies\b1r6yiza01\telerik.web.ui.dll
If I open the master page then open the aspx page I don't get the error but when i open just the aspx page I get the error.
Ok so now I see what the problem is but how do I fix it? How did I do this? TIA
7 Answers, 1 is accepted

Please make sure that all references to the Telerik.Web.UI assembly point to the same version as the error message says that there is a version mismatch - an attempt to cast from 2010.1.309.20 to 2010.1.309.35.
In any case it will surely help to delete the cached version of your Web Site (located in [X]:\Windows\Microsoft.NET\Framework\[v2.0.50727 or v4.0.30319]\Temporary ASP.NET Files).
I hope this helps.
Best wishes,
Simon
the Telerik team


I have the same problem and I followed the instruction to delete the cached version of problmed Web Site from both V2.0 and V4.0's Temporpary ASP.NET files. Open the project in visual studio again, the problem "Error Rendering Control", [A]Telerik.Web.UI.RadScriptManager cannot be cast to [B], still exists. And I noticed that after I open the solution, the cached solution is created under V4.0, not under V2.0.
The virtual directory under localhost is .net 2.0. My toolbox only has RadControls Asp.net 20.
In Web.Config, I had
<
httpHandlers>
<
add path="Telerik.Web.UI.WebResource.axd" type="Telerik.Web.UI.WebResource, Telerik.Web.UI, Version=2010.2.713.20, Culture=neutral, PublicKeyToken=121fae78165ba3d4" verb="*" validate="false"/>
</
httpHandlers>
<
pages>
<
controls>
<
add tagPrefix="telerik" assembly="Telerik.Web.UI" namespace="Telerik.Web.UI"/>
</
controls>
</
pages>
<
system.webServer>
<
validation validateIntegratedModeConfiguration="false"/>
<
handlers>
<
add name="Telerik_Web_UI_WebResource_axd" verb="*" preCondition="integratedMode" path="Telerik.Web.UI.WebResource.axd" type="Telerik.Web.UI.WebResource, Telerik.Web.UI, Version=2008.3.1125.20, Culture=neutral, PublicKeyToken=121fae78165ba3d4"/>
</
handlers>
</
system.webServer>
I commented out the telerik reference in system.webServer but made no difference.
Any idea where else could I have set this project to be .net 40 unknowly? Thanks.
The version of the ASP.NET framework your site is running under is configured in the project/website properties dialog.
As another measure of dealing with the problem, please also delete the cached project assemblies in this folder:
[system_drive_letter]:\Users\[username]\AppData\Local\Microsoft\VisualStudio\10.0\ProjectAssemblies
I hope this helps.
Kind regards,
Simon
the Telerik team
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[A]Telerik.Web.UI.RadScriptManager cannot be cast to [B]Telerik.Web.UI.RadScriptManager. Type A originates from 'Telerik.Web.UI, Version 2011.2.915.40, Culture=neutral, PublicKeyToken=121fae78165ba3d4' in the context 'LoadNeither' at location 'C:\Users\xxxxx\AppData\Local\Microsoft\VisualStudio\10.0\ProjectAssemblies\jbvnawzx01\Telerik.Web.UI.dll'. Type B originates from 'Telerik.Web.UI, Version=2011.2.915.40, Culture=neutral, PublicKeyToken=121fae78165ba3d4' in the context 'LoadNeither' at location 'C:\Users\xxxxx\AppData\Local\Microsoft\VisualStudio\10.0\ProjectAssemblies\t0jbeogb01\telerik.web.ui.dll.
I tried deleting the cached locations as explained in this thread and as soon as I reopened VS the locations reappeared with the same message. Please assist with this as soon as possbile. Thanks
james
Please try the following:
1) Remove all references to Telerik.Web.UI from your project
2) Place the Telerik.Web.UI.dll and Telerik.Web.Design.dll in the BIN folder of your app
3) Add references to them
I hope this helps.
Regards,
Genady Sergeev
the Telerik team