When upgrading to UI for WPF R3 2021 (NuGet), we are unable to build our projects because of a broken reference to Microsoft.VisualStudio.DesignTools.Extensibility. We also noticed that for each dll, a corresponding *.DesignTools reference was added to the project when we did the update - maybe there is a connection?
I was able to reproduce the problem by creating a new .NET Framework app (default VS template, .NET Framework 4.8) and adding the Telerik.Windows.Controls.for.Wpf nuget package (see attached screenshot). As soon as the package is added, I get the following IntelliSense warning:
Severity Code Description Project File Line Source Suppression State
Warning Unknown build error, 'Could not load file or assembly 'Microsoft.VisualStudio.DesignTools.Extensibility, Version=16.5.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a' or one of its dependencies. The located assembly's manifest definition does not match the assembly reference. (Exception from HRESULT: 0x80131040)' WpfApp5 Build
When trying to build the project, I get the following error:
Severity Code Description Project File Line Source Suppression State
Error Unknown build error, 'Cannot resolve dependency to assembly 'Microsoft.VisualStudio.DesignTools.Extensibility, Version=16.5.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a' because it has not been preloaded. When using the ReflectionOnly APIs, dependent assemblies must be pre-loaded or loaded on demand through the ReflectionOnlyAssemblyResolve event.' WpfApp5 Build
Manually adding the nuget package "Microsoft.VisualStudio.DesignTools.Extensibility" resolves the problem.
I would expect the telerik packages to reference the mentioned package as their dependency if it is required (allowing Visual Studio to resolve the missing reference automatically). If this is not possible for some reason, this should at least be noted in the documentation.
Regards
Simon Müller
Hofmann Fördertechnik GmbH