When using WinForms and WPF report viewers to show reports that are hosted in a Telerik Report Server instance or resolved using a REST service, a few additional libraries need to be referenced. Below is the list of these libraries along with a brief explanation of how to install and reference them.
Telerik.Reporting.Services.HttpClient.dll - this assembly containes the client used to make requests and process response from the REST service Web API. The assembly can be found in the \bin subfolder of the Telerik Reporting installation folder. Make sure the CopyLocal property is set to true.
System.Net.Http.Formatting.dll - contains classes for serializing and deserializing HTTP message body in a format based on the requested media type.
System.Net.Http.dll - contains classes of HTTP attributes.
Newtonsoft.Json.dll - a popular high-performance JSON framework for .NET
The recommended way of obtaining the three third-party assemblies is via NuGet package. The package that contains all three of them is Microsoft ASP.NET Web API Client v.4.0.30506 NuGet package. Note that the higher versions of this package require updating the project's target framework to .NET 4.5 or later.