Build Error on .NET 5

[PiotrekPKP]

After upgrading from .NET 5 preview 7 to .NET 5 RC 2 I'm getting this error on project build:
Microsoft.NET.Sdk.targets(934, 5): [NETSDK1130] Referencing a Windows Metadata component directly when targeting .NETCoreApp,Version=v5.0 is not supported. Use the C#/WinRT projection tool (https://aka.ms/cswinrt) or a provided projection for this target.
To reproduce:
Create WPF app using .NET 5, install newest version of ModernWpfUI (I'm getting error on older versions too), run build.
Thanks in advance!

[PiotrekPKP]

I'm using proper target framework name and latest preview. It's because of that Nuget package.

[Kinnara]

The project needs to target net5.0-windows10.0.18362.0 or higher, since this library calls WinRT APIs. You can find related documentation here. The app will still be able to run on older versions of Windows.

[eltechnic0]

Now that NET 5 and VS2019 16.8 are out, this problem is still there and more relevant. Could you release a new version updated for this?

[rasyidf]

After targeting net5.0-windows10.0.18362.0 as you've said earlier throw another error:

Referencing a Windows Metadata component directly when targeting .NETCoreApp,Version=v5.0 is not supported. Use the C#/WinRT projection tool (https://aka.ms/cswinrt) or a provided projection for this target.

Based on this issue stated that

We should update the error message (or perhaps just the link pointed at by https://aka.ms/cswinrt) to make it clear that the fix is to reference the Microsoft.Windows.CsWinRT NuGet package.

and after adding the references, there are some conflict like.

The type 'Color' exists in both 'Microsoft.Windows.SDK.NET, Version=10.0.18362.10, Culture=neutral, PublicKeyToken=31bf3856ad364e35' and 'System.Runtime.WindowsRuntime, Version=4.0.14.0, Culture=neutral, PublicKeyToken=b77a5c561934e089'

Edit:

It's working, I just explicitly referenced Windows.UI.Color (as for my cases)

[rfloresarg]

Hi, I have a project made in VS2019 WPF net core 3.1 and the package ModernWPF works great. When try migrate to Net 5, I can´t run the project and give it me this error

NETSDK1130 Referencing a Windows Metadata component directly when targeting .NETCoreApp,Version=v5.0 is not supported. Use the C#/WinRT projection tool (https://aka.ms/cswinrt) or a provided projection for this target. SPCMAX C:\Program Files\dotnet\sdk\5.0.100\Sdks\Microsoft.NET.Sdk\targets\Microsoft.NET.Sdk.targets 934

I install the nuget package Microsoft.Windows.CsWinRT and try run the project and give it me this error.

System.Windows.Markup.XamlParseException: ''Initialization of 'ModernWpf.ThemeResources' threw an exception.' Line number '12' and line position '18'.'
TypeInitializationException: The type initializer for 'ModernWpf.ThemeManager' threw an exception.
TypeInitializationException: The type initializer for 'ModernWpf.ColorsHelper' threw an exception.
PlatformNotSupportedException: Operation is not supported on this platform. (0x80131539)

I just only installed the package Microsoft.Windows.CsWinRT. It´s necessary make some kind of configuration on project?

Thanks in advance!

[ghost1372]

@rfloresarg just change targetframework to this:
net5.0-windows10.0.18362.0

[rfloresarg]

net5.0-windows10.0.18362.0

Thanks for your help!

[skel35]

How can I still use ModernWpf in .NET 5 if I do not want to build separately for Windows 10.0.18362+, but for all Windows versions supported by .NET 5?

[ShankarBUS]

@skel35,

It's just the target SDK!

It will work older Windows versions!

Try it out yourself 🙃.

[ghost1372]

How can I still use ModernWpf in .NET 5 if I do not want to build separately for Windows 10.0.18362+, but for all Windows versions supported by .NET 5?

I created a custom version and I removed winRT dependency you can find it in my repo

[skel35]

Thanks, @ShankarBUS @ghost1372 !
I haven't used OS versions in target framework monikers before, so I misunderstood what it means.
I'll test this on an older OS when I can, but there should be no issues.
Here's a relevant doc for someone who might misunderstand it as I did: https://docs.microsoft.com/en-us/dotnet/standard/frameworks#os-version-in-tfms

[ilovegabagoolsomuch]

just change targetframework to this:
net5.0-windows10.0.18362.0 or newer

Can reproduce, this fixes everything for me. Thanks for the fix! It's quite important for me to use the non-forked Nuget versions.