I'm using Visual Studio 2015, Telerik Reporting 10.2.16.1025 and Visual Studio Online (hosted Team Foundation).
I've got a report project built and it works and runs just fine. If I publish it manually it works just fine.
The problem comes in when I try to set it up for the continuous integration so I don't have to push it to our QA server a bunch of times during the day. VSO just doesn't want to make use of the Report viewer dlls no matter what I try. I've got copy local set. I've even added them to the solution and checked them into source control (team foundation source control). Nothing works.
The only thing that did work was setting up a private NuGet server and making use of the Nuget package provided by Telerik.
BUT
When I do that,we can no longer make use of the designer in visual studio.According to the forums, we can only use the GAC version of the dlls if we want to use the designer.
Is there some trick to be able to swap out the GAC dlls with a hosted set or a set that's checked in? Again, this is a hosted TFS so I have no ability to install them on the server.
6 Answers, 1 is accepted

Here are the initial errors I'm getting, by the way.
C:\Program Files (x86)\MSBuild\14.0\bin\Microsoft.Common.CurrentVersion.targets (1820, 5)
C:\Program Files (x86)\MSBuild\14.0\bin\Microsoft.Common.CurrentVersion.targets(1820,5): Warning MSB3245: Could not resolve this reference. Could not locate the assembly "Telerik.Reporting, Version=10.1.16.615, Culture=neutral, PublicKeyToken=a9d7983dfcc261be, processorArchitecture=MSIL". Check to make sure the assembly exists on disk. If this reference is required by your code, you may get compilation errors.
C:\Program Files (x86)\MSBuild\14.0\bin\Microsoft.Common.CurrentVersion.targets (1820, 5)
C:\Program Files (x86)\MSBuild\14.0\bin\Microsoft.Common.CurrentVersion.targets(1820,5): Warning MSB3245: Could not resolve this reference. Could not locate the assembly "Telerik.Reporting.Services.WebApi, Version=10.1.16.615, Culture=neutral, PublicKeyToken=a9d7983dfcc261be, processorArchitecture=MSIL". Check to make sure the assembly exists on disk. If this reference is required by your code, you may get compilation errors.
C:\Program Files (x86)\MSBuild\14.0\bin\Microsoft.Common.CurrentVersion.targets (1820, 5)
C:\Program Files (x86)\MSBuild\14.0\bin\Microsoft.Common.CurrentVersion.targets(1820,5): Warning MSB3245: Could not resolve this reference. Could not locate the assembly "Telerik.ReportViewer.Mvc, Version=10.1.16.615, Culture=neutral, PublicKeyToken=a9d7983dfcc261be, processorArchitecture=MSIL". Check to make sure the assembly exists on disk. If this reference is required by your code, you may get compilation errors.
Telerik Reporting must be installed on the dev machine in order VS designers and wizards to work.
As far as it relates VSO, please check Online build can't resolve references(msdn forum) . You can create packages with automatic restore to have the project built. Use a private Nuget feed due to the License agreement's terms. Telerik Reporting assemblies can be used in build and test environments, or they can be bin-deployed for other developers not working on the reporting part.
I hope this helps.
Regards,
Stef
Telerik by Progress

By private Nuget feed, I do not refer to http://nuget.telerik.com. The Nuget packages by Telerik Reporting uploaded at http://nuget.telerik.com are for usage in ASP.NET Core Web Applications - HTML5 Report Viewer in ASP.NET Core. VS Report Designer and wizards will not work in ASP.NET Core projects, even if the product is installed on the machine. Settings should be applied manually.
For other type of projects, you can create private Nuget feed to distribute the assemblies used in your application. When the dev machine has Telerik Reporting installed, you will be able to load VS reports in the VS Report Designer, as long as referenced assemblies are of the same version as the one installed on the machine.
If Telerik Reporting is not installed on the machine, the Dlls distributed through the private Nuget feed will be enough to have the solution built in VS, but VS Report Designer and Toolbox items will not appear.
Regards,
Stef
Telerik by Progress

Mots probably the version of the DLLs in the Nuget feed is different than the installed one. Please check the attached video that illustrates our test.
In general, the Upgrade Wizard operates from within Visual Studio. On installing Telerik Reporting, the MSI adds assemblies in the GAC, and registers the installation folder of DLLs for the VS Upgrade Wizard. When you run the Wizard it check's the project items like references, configuration files, reports, control registrations and updates them, where references start pointing to the local installation folder and the installed version.
Regards,
Stef
Telerik by Progress