The Telerik UI for ASP.NET AJAX suite is not tested and supported under MVC. They are based on the web form paradigm and heavily rely on the web form server lifecycle that is not available in an MVC environment. You can only add the AJAX controls to a standard web form in an MVC project. The Razor engine is not supported by the Telerik UI for ASP.NET AJAX controls.
We recommend using the UI for ASP.NET MVC, the Telerik product built from the ground up to support the principles of MVC development
in your MVC projects.
If you have general questions about the UI for ASP.NET AJAX controls, you can post them in the General Discussions forum section
If you have questions about a specific control, you can post them in their respective forum under the UI For ASP.NET AJAX forum