Add .NET Core 3.0 WinForms/WPF/OffScreen examples

[kpreisser]

Add a WinForms, WPF and OffScreen example using .NET Core 3.0. For this, I added new .netcore.csproj files in the existing project folders, and (for WinForms) adjusted the output of the status bar to display the .NET Core version.
See cefsharp/CefSharp#2796

Current limitations of using CefSharp.WinForms, CefSharp.Wpf and CefSharp.OffScreen with .NET Core 3.0:

• You still need to have .NET Framework 4.5.2 or higher installed, as the CefSharp.BrowserSubprocess.exe is still used.
• The project file needs to update the references of CefSharp.WinForms/CefSharp.WPF/CefSharp.OffScreen, as well as CefSharp.Core and CefSharp to use <Private>true</Private>, as otherwise the CoreCLR would not load these libraries as they would not be specified in the .deps.json file.
• When publishing a self-contained app using a runtime identifier win-x64 or win-x86, you need to set the Platform property to x64 or x86; as otherwise it would be AnyCPU and the check in the .targets file of the NuGet package would fail.
  Example:
  x86: dotnet publish -f netcoreapp3.0 -r win-x86 -p:Platform=x86
  x64: dotnet publish -f netcoreapp3.0 -r win-x64 -p:Platform=x64

The application can also be published as single EXE file by adding -p:PublishSingleFile=true.

Thank you!

[amaitland]

Please add the examples to their own solution as we still need to support older versions of VS.

CefSharp.MinimalExample.netcore.sln appears to be a convention that I've seen MS use, open to other suggestions.

[kpreisser]

OK, I reverted the changes to CefSharp.MinimalExample.sln and created a new CefSharp.MinimalExample.netcore.sln.

[amaitland]

Great, thanks 👍

How practical do you think it is to reuse the code files? By this I mean just using a different .csproj file for the .Net Core projects?

I see examples of this in https://github.com/microsoft/WPF-Samples/tree/master/Input%20and%20Commands/CaptureUnCaptureMouse

Thoughts?

[kpreisser]

How practical do you think it is to reuse the code files? By this I mean just using a different .csproj file for the .Net Core projects?

I see examples of this in https://github.com/microsoft/WPF-Samples/tree/master/Input%20and%20Commands/CaptureUnCaptureMouse

Thanks, I applied this by creating new .netcore.csproj files in the existing CefSharp.MinimalExample.WinForms and CefSharp.MinimalExample.Wpf folders, so that the code files are reused.

A minor drawback of this approach is that when you want to switch between the .NET Core and .NET Framework solutions, you might have to delete the existing obj folder to avoid errors from the build system.

[amaitland]

Great, thanks 👍 Will merge this after 75.1.142 has been released and the WPF P/Invoke issue has been resolved.

[kpreisser]

I have also added a .NET Core project file for CefSharp.MinimalExample.OffScreen.

Note: The change to Process.Start is needed because UseShellExecute is false by default in .NET Core.

Will merge this after 75.1.142 has been released and the WPF P/Invoke issue has been resolved.

Once this is released, we can remove the <PackageReference Include="CefSharp.Common" ... /> in the .netcore.csproj files.

Thanks!

[amaitland]

Version 75.1.142 should appear on Nuget.org shortly.

[kpreisser]

Thanks, I upgraded the .NET Core examples to 75.1.142. The WPF example is working now.

I also updated the README.md to mention support for .NET Core and the current limitations, is this OK?

Thanks!

[amaitland]

I also updated the README.md to mention support for .NET Core and the current limitations, is this OK?

Excellent start, thanks 👍

[amaitland]

Thanks for your hard work on this 👍 Merging now.