Telerik UI for ASP.NET controls are added automatically to the Visual Studio Toolbox during MSI installation.
If you are installing Telerik UI for ASP.NET AJAX from a ZIP distribution, however, you can do this manually by following the steps below:
Log into your account and download the Telerik_UI_for_ASP.NET_AJAX_20xx_x_xxx_Dev_hotfix.zip hotfix zip installation
Open your application in Visual Studio.
Expand the Toolbox.
Expand the General section. Alternatively, you can create a new section by selecting the Add Tab option from the context menu (right click anywhere in the toolbox). When the new tab is added you can choose its name (e.g. Telerik UI for ASP.NET AJAX RX YYYY).
Right-click in the General section (or the new one you just created) and open Choose Items.
On the .NET Framework Components tab, click Browse.
Browse to the installation folder, open the Bin45 folder and select the Telerik.Web.UI.dll.
If the Windows Installer MSI Package was used to install Telerik UI for ASP.NET AJAX, the bin45 folder is located in C:\Program Files (x86)\Progress\Telerik UI for ASP.NET AJAX RX YYYY\Bin45. If this folder is missing, download the hotfix installation and obtain the Telerik.Web.UI.dll assembly from it as instructed in point 1 in the above list.
If the ZIP was used to install the Telerik controls, the Bin45 folder is located in the folder where the installation files have been unzipped.
If you want to add Telerik controls for .NET 3.5 or .NET 4.0 web project you should select the Telerik.Web.UI.dll from the C:\Program Files (x86)\Progress\UI for ASP.NET AJAX RX YYYY\Bin35 or ~/Bin40 folder.
If the controls do not appear in the ToolBox, please make sure that the project is of type ASP.NET Web Forms site or application.
You can find more information in the Design-time Troubleshooting section.