kb(common): add article for activating telerik license with an assembly

Author: attilaantal

knowledge-base/common-activate-telerik-license-with-assembly.md

@@ -0,0 +1,78 @@
+---
+title: Activate your Telerik License with an Assembly (.dll)
+description: Create an Assembly containing your License Key that can be added to the bin folder of Web site projects to activate the Telerik License.
+type: how-to
+page_title: Activate your Telerik License with an Assembly (.dll)
+slug: common-activate-telerik-license-with-assembly
+tags: activate,telerik,license,assembly,dll,class library
+ticketid: 1678618
+res_type: kb
+---
+
+## Environment
+
+| Version | Product |
+| ---     | ---     |
+| 2025 Q1 or later | Telerik UI for ASP.NET AJAX |
+
+## Description
+
+I want to be able to activate the Telerik License without creating classes or adding code to the `App_Code` folder.  I want to ensure proper implementation of Telerik UI for ASP.NET AJAX licensing in a setup where an ASP.NET Web site project is used assemblies are referenced by adding the dll to the bin folder.
+
+This knowledge base article also answers the following questions:
+- Can I activate a the Telerik License using a `DLL` in the `Bin` folder?
+- How to activate the Telerik License without adding any code to the `App_Code` folder?
+- How to resolve assembly mismatches with Telerik.Licensing.Runtime.dll during production?  
+
+## Solution  
+
+### Creating a License Key Assembly
+
+1. In Visual Studio [Create a Class Library (.NET Framework)](https://learn.microsoft.com/en-us/dotnet/core/tutorials/library-with-visual-studio) project and name it something like TelerikLicenseKey
+2. Reference the Telerik Licensing
+   - **Option 1**: Install the `Telerik.Licensing` NuGet package the project through the Nuget Package Manager
+   - **Option 2**: Add a [NuGet PackageReference](https://learn.microsoft.com/en-us/nuget/consume-packages/package-references-in-project-files) to the project file (`.csproj` or `.vbproj`).
+      ````XML
+      <ItemGroup>
+         <PackageReference Include="Telerik.Licensing" Version="[1.4.6,2.0)" />
+      </ItemGroup>
+      ````
+3. Download your Telerik License Key:  
+   - Navigate to the [License Keys](https://www.telerik.com/account/your-licenses/license-keys) page in your Telerik account.  
+   - Locate the Telerik UI for ASP.NET AJAX row and click the "View Key" link. Select the programming language and Copy the license key.
+
+4. Add the License Key to the project
+   - In the Class Library, add the copied License Key Script to `Properties > AssemblyInfo.cs`
+
+5. Build the project then copy the compiled assembly e.g. `TelerikLicenseKey.dll` to the `Bin` folder of the Web site project you are aiming to activate the Telerik License for.
+
+>This works as if adding the License key to a Class in the `App_Code\` folder, except that the Class Library will need to be maitnained separately to keep the `Telerik.Licensing.Runtime.dll` up-to-date in case the Telerik UI gets updated.
+
+### Addressing Assembly Mismatches
+
+If you encounter assembly mismatch errors, follow these steps:  
+
+1. **Use Binding Redirects**:  
+   - Add a binding redirect to your `web.config` to resolve mismatches between versions of `Telerik.Licensing.Runtime.dll`. Example:  
+     ```xml  
+     <?xml version="1.0"?>  
+     <configuration>  
+       <runtime>  
+         <assemblyBinding xmlns="urn:schemas-microsoft-com:asm.v1">  
+           <dependentAssembly>  
+             <assemblyIdentity name="Telerik.Licensing.Runtime" publicKeyToken="98bb5b04e55c09ef" culture="neutral" />  
+             <bindingRedirect oldVersion="0.0.0.0-1.6.5.0" newVersion="1.6.5.0" />  
+           </dependentAssembly>  
+         </assemblyBinding>  
+       </runtime>  
+     </configuration>  
+     ```  
+
+2. **Version Compatibility**:  
+   - Ensure the `Telerik.Licensing.Runtime.dll` version referenced to the Class Library matches the Telerik version in your Web site project.
+
+## See Also  
+
+- [License Key Installation](https://www.telerik.com/products/aspnet-ajax/documentation/licensing/license-key#setup-your-license-key)  
+- [Web Application Projects vs. Web Site Projects](https://learn.microsoft.com/en-us/previous-versions/aspnet/dd547590(v=vs.110))  
+- [Adding Binding Redirects in Web.config](https://learn.microsoft.com/en-us/dotnet/framework/configure-apps/redirect-assembly-versions)