Avalonia Designer Preview process exited。 Could not load file or assembly。

[submaie]

Describe the bug

The preview window displays error messages。

To Reproduce

The basic window code is Avalonia's default code:

<Window xmlns="https://github.com/avaloniaui"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
        xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
        mc:Ignorable="d" d:DesignWidth="800" d:DesignHeight="450"
        x:Class="SanxingReport.MainWindow"
        Title="SanxingReport">
    Welcome to Avalonia!
</Window>

AvaloniaVS plugin version

12.1.1.0

Avalonia version

12.0.4

Visual Studio version

18.4.2

Relevant log output

03:17:04.696 [Information] [PreviewerProcess (#16851234)] [33424] Connection initialized
03:17:04.709 [Error] [PreviewerProcess (#16851234)] [33424] <= Unhandled exception. System.Reflection.TargetInvocationException: Exception has been thrown by the target of an invocation.
03:17:04.709 [Error] [PreviewerProcess (#16851234)] [33424] <=  ---> System.IO.FileNotFoundException: Could not load file or assembly 'Avalonia.Headless, Version=11.2.0.0, Culture=neutral, PublicKeyToken=c8d484a7012f9a8b'. 系统找不到指定的文件。
03:17:04.709 [Error] [PreviewerProcess (#16851234)] [33424] <= File name: 'Avalonia.Headless, Version=11.2.0.0, Culture=neutral, PublicKeyToken=c8d484a7012f9a8b'
03:17:04.709 [Error] [PreviewerProcess (#16851234)] [33424] <=    at AvaloniaUI.Previewer.DesignerSupport.Remote.RemoteDesignerEntryPoint.StartAvaloniaApplication(CommandLineArgs args)
03:17:04.709 [Error] [PreviewerProcess (#16851234)] [33424] <=    at AvaloniaUI.Previewer.DesignerSupport.Remote.RemoteDesignerEntryPoint.StartAvaloniaApplication(CommandLineArgs args)
03:17:04.709 [Error] [PreviewerProcess (#16851234)] [33424] <=    at AvaloniaUI.Previewer.DesignerSupport.Remote.RemoteDesignerEntryPoint.SetupPreviewer(String[] cmdline)
03:17:04.709 [Error] [PreviewerProcess (#16851234)] [33424] <=    at AvaloniaUI.Previewer.DesignerSupport.Remote.RemoteDesignerEntryPoint.Main(String[] cmdline)
03:17:04.709 [Error] [PreviewerProcess (#16851234)] [33424] <=    at System.Reflection.MethodBaseInvoker.InterpretedInvoke_Method(Object obj, IntPtr* args)
03:17:04.709 [Error] [PreviewerProcess (#16851234)] [33424] <=    at System.Reflection.MethodBaseInvoker.InvokeDirectByRefWithFewArgs(Object obj, Span`1 copyOfArgs, BindingFlags invokeAttr)
03:17:04.709 [Error] [PreviewerProcess (#16851234)] [33424] <=    --- End of inner exception stack trace ---

Additional context

After inspection, it was found that Avalonia Designer Preview requires Avalonia.Headless, Version=11.2.0.0, but in the local NuGet cache, the version of Avalonia.Headless is only as shown in the picture below：
12.0.0
12.0.3
12.0.4

[maxkatz6]

@submaie unfortunately I am not able to reproduce this issue. Have you reproduced it on a template project too? If you only reproduced it on your actual project, it's likely that dependencies are in play here.

Previewer requires Avalonia.Headless, but it matches it with your Avalonia version. So, it must be one of these 12.0 you listed. It was failing back to 11.2.0 only if previewer failed to resolve version from your project - but in previous VS extension versions. In newer versions it falls back to 12.0. And yeah, 11.2.0 exists on nuget.

Can you double check that you have latest VS extension installed?
Does it fix the problem, if you include "Avalonia.Headless" 12.0 in your project? (can be left unused)

[submaie]

AvaloniaVS :

My project include "Avalonia.Headless" 12.0, The error still occurs：

08:04:17.177 [Information] [PreviewerProcess (#24840161)] [36952] Connection initialized
08:04:17.225 [Error] [PreviewerProcess (#24840161)] [36952] <= Unhandled exception. System.Reflection.TargetInvocationException: Exception has been thrown by the target of an invocation.
08:04:17.225 [Error] [PreviewerProcess (#24840161)] [36952] <=  ---> System.TypeInitializationException: The type initializer for 'SkiaSharp.SKImageInfo' threw an exception.
08:04:17.225 [Error] [PreviewerProcess (#24840161)] [36952] <=  ---> System.DllNotFoundException: Unable to load DLL 'libSkiaSharp' or one of its dependencies: 找不到指定的模块。 (0x8007007E)
08:04:17.225 [Error] [PreviewerProcess (#24840161)] [36952] <=    at SkiaSharp.SkiaApi.sk_colortype_get_default_8888()
08:04:17.225 [Error] [PreviewerProcess (#24840161)] [36952] <=    at SkiaSharp.SkiaApi.sk_colortype_get_default_8888()
08:04:17.225 [Error] [PreviewerProcess (#24840161)] [36952] <=    at SkiaSharp.SKImageInfo..cctor()
08:04:17.225 [Error] [PreviewerProcess (#24840161)] [36952] <=    --- End of inner exception stack trace ---

[maxkatz6]

@submaie is this a project that you can send? Or can you create a minimal project where you see the same issue?
You latest log shows different error - now with Avalonia.Skia. And you might then get Avalonia.Markup.Xaml.Loader one. Can you add these packages and check? But again, previewer should and normally does resolve these packages automatically.

Before that, can you share %LocalAppData%\AvaloniaUI\com.AvaloniaUI.Net.VisualStudio\Previewer\%YOUR_PROJECT_FOLDER%\%YOUR_ASSEMBLY%.previewer.bin file? This file includes nuget package paths for your project.

[maxkatz6]

One thing that I don't understand, is where "11.2.0" comes from.
I checked VS extension "12.1.1.0", and it most definitely falls back to "12.0" instead. I wonder if it makes sense to reinstall the extension.

[submaie]

@maxkatz6 :
I found the reason for the error. I referenced a VC enhancement package from Nuget: VC-LTL, the address is:
https://github.com/Chuyu-Team/VC-LTL5
As long as this package is referenced, Avalonia's preview window will show an error, usually 'file not found'.

I have packaged the minimal example below.
A standalone Avalonia C# project, single file, referencing AvaloniaEdit and VC-LTL.

AvaloniaApplication1.zip

[maxkatz6]

@submaie thanks! I was able to reproduce the issue.

[maxkatz6]

Looks like "net10.0-windows" target is core of the problem.

[submaie]

TFM from "net10.0-windows" change to "net10.0-windows7.0" :

09:23:28.283 [Information] [PreviewerProcess (#64977235)] [2360] Connection initialized
09:23:28.299 [Information] [AvaloniaUI.Previewer.Process.PreviewerProcessFactory] Resolving metadata for 'E:\SanxingReport\ReportGenerator\SanxingReport.csproj' (TFM=net10.0-windows7.0)
09:23:28.299 [Information] [AvaloniaUI.VisualStudio.Extension.Services.CpsAssetsPreviewerMetadataService] Resolving previewer metadata for 'E:\SanxingReport\ReportGenerator\SanxingReport.csproj' [net10.0-windows7.0]
09:23:28.304 [Information] [AvaloniaUI.Previewer.Process.Output.ShadowCopyOutputStrategy] Shadow copy reused at 'C:\Users\马跃新\AppData\Local\AvaloniaUI\com.AvaloniaUI.Net.VisualStudio\Previewer\SanxingReport_3_ZUNeC1UO4R1cY0' (28 files)
09:23:28.303 [Information] [AvaloniaUI.VisualStudio.Extension.Services.CpsAssetsPreviewerMetadataService] Resolving extra packages [Avalonia.Headless, Avalonia.Markup.Xaml.Loader] (Avalonia 12.0.4, net10.0-windows7.0)
09:23:28.457 [Error] [PreviewerProcess (#64977235)] [2360] <= Unhandled exception. System.Reflection.TargetInvocationException: Exception has been thrown by the target of an invocation.
09:23:28.457 [Error] [PreviewerProcess (#64977235)] [2360] <=  ---> System.InvalidCastException: Unable to cast object of type 'AvaloniaUI.Previewer.DesignerSupport.DesignTimeApplicationLifetime' to type 'Avalonia.Controls.ApplicationLifetimes.IClassicDesktopStyleApplicationLifetime'.
09:23:28.457 [Error] [PreviewerProcess (#64977235)] [2360] <=    at SanxingReport.App.OnFrameworkInitializationCompleted() in E:\SanxingReport\ReportGenerator\App.axaml.cs:line 31
09:23:28.457 [Error] [PreviewerProcess (#64977235)] [2360] <=    at Avalonia.AppBuilder.SetupUnsafe()
09:23:28.457 [Error] [PreviewerProcess (#64977235)] [2360] <=    at Avalonia.AppBuilder.Setup()
09:23:28.457 [Error] [PreviewerProcess (#64977235)] [2360] <=    at Avalonia.AppBuilder.SetupWithLifetime(IApplicationLifetime lifetime)
09:23:28.457 [Error] [PreviewerProcess (#64977235)] [2360] <=    at AvaloniaUI.Previewer.DesignerSupport.Remote.RemoteDesignerEntryPoint.StartAvaloniaApplication(CommandLineArgs args)
09:23:28.457 [Error] [PreviewerProcess (#64977235)] [2360] <=    at AvaloniaUI.Previewer.DesignerSupport.Remote.RemoteDesignerEntryPoint.SetupPreviewer(String[] cmdline)
09:23:28.457 [Error] [PreviewerProcess (#64977235)] [2360] <=    at AvaloniaUI.Previewer.DesignerSupport.Remote.RemoteDesignerEntryPoint.Main(String[] cmdline)
09:23:28.457 [Error] [PreviewerProcess (#64977235)] [2360] <=    at System.Reflection.MethodBaseInvoker.InterpretedInvoke_Method(Object obj, IntPtr* args)
09:23:28.457 [Error] [PreviewerProcess (#64977235)] [2360] <=    at System.Reflection.MethodBaseInvoker.InvokeDirectByRefWithFewArgs(Object obj, Span`1 copyOfArgs, BindingFlags invokeAttr)
09:23:28.457 [Error] [PreviewerProcess (#64977235)] [2360] <=    --- End of inner exception stack trace ---