Generation of designer file failed, unable to create type telerik RadScriptManager
Posted on 15 July 2009
| problem | quick solution | cause | remarks | references |
Problem
You may get the following warning when you take over someones project where Telerik controls are used, and you haven’t installed Telerik yourself, and open an ASPX page or run the project:
Generation of designer file failed: Unable to create type 'telerik:RadScriptManager'. Could not load file or assembly 'System.Web.Extensions, Version=1.0.61025.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35' or one of its dependencies. The system cannot find the file specified. D:\Project\YourProject\Default.Master
Quick Solution
A simple and quick fix is to do the following:
- Install or reinstall the Telerik controls, either the free demo version or the full licensed verion;
- Remove the Telerik reference from the project;
- Add the Telerik reference back again.
Perhaps not that quick a fix — it takes forever to install Telerik — but after the tedious install experience, you’re all set. And yes, when you open the Help of Visual Studio again, it will take a long time (minutes to hours) before the Telerik help items are fully added.
Cause
The Telerik controls have been compiled with an older version of System.Web.Extensions, probably because for better backwards compatibility. When you simply add the Telerik DLLs to a project, or you use open a project that you copied from another computer, you will receive this error.
Remarks
This Telerik error causes collateral damage if you try to work with it or around it:
You may not notice it the first time around, but if the designer cannot be updated, controls you add inside the ASPX or Master file (code view, designer won’t work), will actually not be added. The result is that IntelliSense doesn’t work for the added controls, even if the controls are as basic as an asp:Label or asp:Button. When you run your code (if your page does not use Telerik you can run your code without the above error), the added controls will not show up on the page in your browser. And even if you used FindControl to try to find where your control is hidden: you won’t find it anywhere!
References
So far, I have not seen any reference of this issue, but if you know one, let me know too, it’d be nice to link it here.
Don’t follow the advised on the TechNet, MS Connect and MSDN forums, they are time-consuming and don’t work if you have a newer version of .NET installed like .NET 4.0. Instead, read this and easily fix this hard-to-resolve error by simply changing one registry value. read article
Ever tried to shrink a volume? Ever wondered why you cannot shrink a volume smaller than half its size? Ever wondered what $MFTMirr is all about and what it’s doing in the middle of your drive? Or do you just want to get the biggest available free space and shrink your drive? Then this article is for you — read article
Have you ever received this error using Windows System Backup and Restore Center? Never managed to get rid of it or it mysteriously keeps coming back? Here’s a lightweight and easy solution — read article
1 Response to Generation of designer file failed, unable to create type telerik RadScriptManager
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I had the same problem, but it turned out that the 1.0.61025.0 version of the system.web.extensions was not installed on my development machine…
Downloading and installing ASP.NET 2.0 AJAX Extensions 1.0 from: http://www.asp.net/ajax/downloads/archive/ fixed the problem.