Error Creating Control

[Merso Djul]

Hi

I have problem when I try to add some controls (not all, i.e. RadCalendar) on page instead of control it appears box with error message like this:>> Error Creating Control - RadCalendar1Could not load file or assembly 'Telerik.Web.UI, Version=2009.1.311.35, Culture=neutral, PublicKeyToken=121fae78165ba3d4' or one of its dependencies. The system cannot find the file specified<<. I've read some posts and checked if assembly exist (Telerik.Web.UI), and it does in web.config and in assemblies folder. What is causing this, and what is solution?

Thanks

Merso

[Erjan Gavalji]

Hi Merso Djul,

This error message most often happens when using Visual Studio 2008 without the Service Pack installed. In this case, the IDE cannot resolve the binding between the Telerik.Web.UI and Telerik.Web.Design assemblies (Telerik.Web.UI being in the local BIN folder and Telerik.Web.Design in the GAC).

My suggestion is to install Visual Studio 2008 SP1.
The other possible approach is to copy the Telerik.Web.UI assembly to the [VisualStudioInstallationFolder]\Common7\IDE\PrivateAssemblies folder. This way the Visual Studio IDE would be able to properly resolve the reference between the two assemblies and load the designers. This approach is not the best one though, as you would need to perform the copy each time we release a new version of the suite.

Let me know if this helps.

Kind regards,
Erjan Gavalji
the Telerik team

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[Analogue]

I am experiencing exactly the same problem (and I've seen others have the same too) - I run VS2008 SP1.

I've tried all the work arounds I've seen in the forum on my main vista business work machine and I've tried it all again on a brand new machine with a virgin install of Win 7 64 + VS 2008 + SP1 + Rad controls 2009 q3. I just get the 'cannot create controls' message in the IDE.

Now forgive me if i'm way out here, but I bought into a set of controls that work 'with' VS - so to say that VS fails to connect the assemblies is sure wrong. VS is the dog, Telerik controls is the tail since when did we flip that concept??

I have around 200 days left on my subscription - I honestly cannot justify having that sub for a product that doesn't install and work........because my dev express ones do without any problems. Frustrated? You bet.

[Erjan Gavalji]

Hi Analogue,

I'm sorry for the frustration, our aim is exactly the opposite. I can only point out that we list all the reasons for this problem we've been able to identify so far.

Anyways, the most important thing now is to fix the designer load on your side. Can you give me some more details on the project you get the error in? Does it use any special entries in the web.config? Do you run it in Medium Trust, or do you run it in Full trust? Do you run the Visual Studio IDE as an administrator?

Can you try creating a very basic website and add a RadControl to it? Can you verify that you have a Telerik.Web.Design assembly in the GAC, which version matches the version of the Telerik.Web.UI assembly, which has been copied to the website BIN?

I'm looking forward to your reply.

Best wishes,
Erjan Gavalji
the Telerik team

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[Analogue]

I know you mean good and appologies for any bad notes! Not my intention - just got a big work load and an embarrassing situation where I can't deliver urgent work because of this glitch.

Ok here's where I'm at.

My set up Windows Vista Business 32bit fully patched, VS2008 SP1, running as administrator, UAC switched the hell off.

I un-installed everything Telerik, deleted asp.net temp cache files, removed anything telerik in iis and anywhere I saw it including all previous version installs & left overs. Rebooted & re-installed using MSI (RadControls_for_ASP.NET_AJAX_2009_3_1103_dev.msi). For the Install options I choose only 3.5 stuff and excluded 2.0.

I Created a new website (Website1) pulled in a Rad menu which displays an error where the  control should render 'Error Creating Control' 'Failed to create designer etc etc. I get similar messages when I drag other telerik controls on too.

Then I checked the GAC (which I assume is C:/Windows/Assembly from the google searches I've done) - I see there is a file Telerik.Web.Design - 2009.3.1103.35 which seems correct.

Beyond this I'm out of my depth.

[Analogue]

bingo.

I just restarted my machine then added Telerik.Web.UI assembly to the [VisualStudioInstallationFolder]\Common7\IDE\PrivateAssemblies folder. And now it all works.

I tried that yesterday and it didn't work - now it does. Which is also scary.....but I can hopefully get the project I'm working on out today.

If you require any further info please let me know and I'll post what ever is required.

[Erjan Gavalji]

Hi Analogue,

I'm glad the problem is solved now (please, excuse the delay in my reply - I was too busy with some meetings and I wanted to personally deal with the problem you're experiencing).

The only reason I can guess (now that you mentioned the operating system restart) is that there could have been a devenv.exe process hanging on your machine, which the restart has solved. While I'm not sure about that, I think that a possible hanged IDE instance could have prevented the proper load of the design assembly.

We will try reproducing this locally so that at least we will know the exact case and hopefully help other customers faster.

P.S. Please, find your Telerik account updated for reporting your solution!

Best regards,
Erjan Gavalji
the Telerik team

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Watch a video on how to optimize your support resource searches and check out more tips on the blogs.