If you are using third-party .NET component libraries such as Telerik or DevExpress, you may come across the error message below while trying to include controls in your page.
Server Error in ‘/TestASPNET’ Application.
Parser Error
Description: An error occurred during the parsing of a resource required to service this request. Please review the following specific parse error details and modify your source file appropriately.
Parser Error Message: Unknown server tag ‘telerik:RadScriptManager’.
Solution
Make sure to include 2 DLL files below in your project references of Visual Studio:
- Telerik.Web.UI
- Telerik.Web.UI.Skins
If you are still receiving the error above, add a reference to your Telerik assembly in your web.config file. You can use the following lines to make this reference.
<system.web>
<pages viewStateEncryptionMode="Always" controlRenderingCompatibilityVersion="3.5" clientIDMode="AutoID">
<controls>
<add tagPrefix="telerik" namespace="Telerik.Web.UI" assembly="Telerik.Web.UI"/>
</controls>
</pages>
</system.web>