.NET Core 3 support request

Description

I would like to use FsXaml with .NET Core 3 .NET Core 3 brings support for WPF, but it doesn’t seem to work with FsXaml

Repro steps

Please provide the steps required to reproduce the problem

Using the latest preview for .NET Core 3 -

1. Create a new dotnet core 3.0 application with WPF support -

project.fsproj

<Project Sdk="Microsoft.NET.Sdk.WindowsDesktop">

    <PropertyGroup>
        <OutputType>WinExe</OutputType>
        <TargetFramework>netcoreapp3.0</TargetFramework>
        <RootNamespace>MyNamespace</RootNamespace>
        <UseWPF>true</UseWPF>
    </PropertyGroup>

    <ItemGroup>
        <PackageReference Include="Elmish.WPF" Version="3.1.0"/>
        <PackageReference Include="FsXaml.Wpg" Version="3.1.6"/>
    </ItemGroup>
</Project>

1. Add a XAML file to the project.

2. Build the project.

Expected behavior

Project builds and I can start using the Type provider for the XAML file in my code.

Actual behavior

Build outputs an error as follows

C:\Program Files\dotnet\sdk\3.0.100-preview8-013656\Sdks\Microsoft.NET.Sdk.WindowsDesktop\targets\Microsoft.WinFX.targets(243,9): error MC1000: Unknown build error, 'Object reference not set to an instance of an object.'  [C:\Users\dam5s\workspace\epub-desktop\epub-desktop\epub-desktop.fsproj]  

Known workarounds

None that I know of. I’m using a C# project with my XAML files instead.

Related information

• Windows 10 Pro
• Latest stable version
• 3.0.100-preview8-013656

[mattstermiller]

I took the project files and other changes from @amazingant 's repo that he linked above, applied them in a branch on my fork, and worked with it to get as far as I could.

Here is the progress I was able to make:

• The core projects of this library, FsXaml.Wpf and FsXaml.Wpf.TypeProvider, have the new sdk project file format and target both netcoreapp3.0 and net45. They build and pass tests.
• The FsXaml.Wpf.Blend project has the new sdk project file format but only targets net45 since its dependency System.Windows.Interactivity.WPF is only compatible with .NET framework. It was last updated in 2013.
• 3 of the demo projects build with Visual Studio 2019 and run. 1 more builds but crashes on startup with a XamlParseException. The other 2 fail to build with “The provided method is marked as an abstract method; therefore, it should not define an implementation” and “Cannot inherit a sealed type” errors. I don’t know how to fix these since the TypeProviders SDK seems to have changed quite a bit since the last release of FsXaml and I don’t know if there were fundamental design changes regarding generating sealed vs. abstract types.

I need guidance on how to fix the demo apps or possibly the library to get this working.

Also, I noticed that the FAKE build script is very out-of-date. I was unable to use it and resorted to using paket, the dotnet SDK, and VS (and for building the demo projects, manually copying the library DLLs to the bin folder).

[xp44mm]

request to support latest version, the fsproj file like this:

<Project Sdk="Microsoft.NET.Sdk">

  <PropertyGroup>
    <OutputType>WinExe</OutputType>
    <TargetFramework>net7.0-windows</TargetFramework>
    <UseWPF>true</UseWPF>
    <UseWindowsForms>False</UseWindowsForms>
  </PropertyGroup>

  <ItemGroup>
    <Resource Include="FirstMetroWindow.xaml" />
    <Resource Include="App.xaml" />
    <Compile Include="FirstMetroWindow.fs" />
    <Compile Include="App.fs" />
  </ItemGroup>


  <ItemGroup>
    <PackageReference Include="FsXaml.Wpf" Version="3.1.6" />
    <PackageReference Include="MahApps.Metro" Version="2.4.9" />
    <PackageReference Include="System.Reactive" Version="5.0.0" />
  </ItemGroup>

</Project>