Hello, I hope I posted in the correct forum... I'm in the progress of migrating our WPF from .Net 4.7.2 to .Net Core 6 I run into issues with our test projects that reference WPF and use Microsoft Fakes Please see my demo repo here: https://github.com/RoyRosenberg/msFakesWPF Basically, the problem can be described like the following: Class Library project with <UseWPF>true</UseWPF> The project contains ControlDemo class that inherits from UserControl class MSTest project with reference to the class library project I added fakes assembly to the class lib. project When trying to compile, I got the following error Error CS7069 Reference to type 'DependencyObject' claims it is defined in 'WindowsBase', but it could not be found The error is duplicated 20 times, so I got 20 errors in the error list window: Please help me find out the problem Thanks in advance, Roy

Hi LP, The issue is fixed in the latest version of VS (17.4 I guess).

Net Core 6: Microsoft Fakes and WPF Issue

Roy Rosenberg 1

Hello,

I hope I posted in the correct forum...

I'm in the progress of migrating our WPF from .Net 4.7.2 to .Net Core 6
I run into issues with our test projects that reference WPF and use Microsoft Fakes
Please see my demo repo here:

https://github.com/RoyRosenberg/msFakesWPF

Basically, the problem can be described like the following:

Class Library project with <UseWPF>true</UseWPF>
The project contains ControlDemo class that inherits from UserControl class
MSTest project with reference to the class library project
I added fakes assembly to the class lib. project

When trying to compile, I got the following error

Error CS7069 Reference to type 'DependencyObject' claims it is defined in 'WindowsBase', but it could not be found

The error is duplicated 20 times, so I got 20 errors in the error list window:

Please help me find out the problem
Thanks in advance,
Roy

Tianyu Sun-MSFT 31,246 Reputation points Microsoft Vendor

2022-08-24T10:01:24.27+00:00

Hi @Roy Rosenberg ,

Welcome to Microsoft Q&A forum. I tested on my side with the demo you shared but the solution built well. Are there some NuGet packages not using the correct version(latest version)? You can try cleaning NuGet cache and then restore NuGet packages. Please also try to clean project cache and VS cache(remove all folders named ComponentModelCache in this path: C:\Users\[username]\AppData\Local\Microsoft\VisualStudio\17.0_XXXXXXXX ) and test again(make a backup in case).
LP 1 Reputation point

2022-11-18T20:36:14.407+00:00

I have the same problem :
Reference to type 'DependencyObject' claims it is defined in 'WindowsBase', but it could not be found

I've tried your advice with no result.
I am considering use Moq, Microsoft Fakes is very problematic

Thanks
LP

1 answer

Roy Rosenberg 1 Reputation point

2022-11-18T22:35:55.253+00:00

Hi LP,
The issue is fixed in the latest version of VS (17.4 I guess).
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Net Core 6: Microsoft Fakes and WPF Issue

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