Updated to WinUI3.

[azchohfi]

Ready to review.

[michael-hawker]

@RosarioPulella feel free to take a quick look, but think we're good for you to move ahead if you want Alex.

[azchohfi]

I'll move ahead for now, since I wanna make sure the signing is working properly.

[Rosuavio]

I could not build the WinUI projects.

Build started...
1>------ Build started: Project: ColorCode.Core, Configuration: Debug Any CPU ------
1>ColorCode.Core -> C:\Users\Rosario\source\repos\ColorCode-Universal\ColorCode.Core\bin\Debug\netstandard1.4\ColorCode.Core.dll
2>------ Build started: Project: ColorCode.HTML, Configuration: Debug Any CPU ------
3>------ Build started: Project: ColorCode.WinUI, Configuration: Debug Any CPU ------
4>------ Build started: Project: ColorCode.UWP, Configuration: Debug Any CPU ------
2>ColorCode.HTML -> C:\Users\Rosario\source\repos\ColorCode-Universal\ColorCode.HTML\bin\Debug\netstandard1.4\ColorCode.HTML.dll
5>------ Build started: Project: ColorCode.BasicTests, Configuration: Debug Any CPU ------
3>C:\Program Files (x86)\Microsoft Visual Studio\2019\Enterprise\MSBuild\Current\Bin\Microsoft.Common.CurrentVersion.targets(2123,5): warning MSB3277: Found conflicts between different versions of "WinRT.Runtime" that could not be resolved.  These reference conflicts are listed in the build log when log verbosity is set to detailed.
3>CSC : error CS1705: Assembly 'Microsoft.WinUI' with identity 'Microsoft.WinUI, Version=3.0.0.0, Culture=neutral, PublicKeyToken=de31ebe4ad15742b' uses 'WinRT.Runtime, Version=1.1.0.0, Culture=neutral, PublicKeyToken=99ea127f02d97709' which has a higher version than referenced assembly 'WinRT.Runtime' with identity 'WinRT.Runtime, Version=1.0.1.33301, Culture=neutral, PublicKeyToken=99ea127f02d97709'
3>Done building project "ColorCode.WinUI.csproj" -- FAILED.
6>------ Build started: Project: ColorCode.WinUITests, Configuration: Debug x64 ------
5>ColorCode.BasicTests -> C:\Users\Rosario\source\repos\ColorCode-Universal\Tests\ColorCode.BasicTests\bin\Debug\netcoreapp2.1\ColorCode.BasicTests.dll
4>ColorCode.UWP -> C:\Users\Rosario\source\repos\ColorCode-Universal\ColorCode.UWP\bin\Debug\uap10.0\ColorCode.UWP.dll
6>C:\Program Files (x86)\Microsoft Visual Studio\2019\Enterprise\MSBuild\Current\Bin\Microsoft.Common.CurrentVersion.targets(2123,5): warning MSB3277: Found conflicts between different versions of "WinRT.Runtime" that could not be resolved.  These reference conflicts are listed in the build log when log verbosity is set to detailed.
6>C:\Users\Rosario\source\repos\ColorCode-Universal\Tests\ColorCode.WinUITests\ColorCode.WinUITests.csproj : XamlCompiler error WMC1006: Cannot resolve Assembly or Windows Metadata file 'C:\Users\Rosario\source\repos\ColorCode-Universal\ColorCode.WinUI\bin\Debug\net5.0-windows10.0.18362.0\ColorCode.WinUI.dll'
7>------ Build started: Project: ColorCode.UWPTests, Configuration: Debug x64 ------
6>CSC : error CS0006: Metadata file 'C:\Users\Rosario\source\repos\ColorCode-Universal\ColorCode.WinUI\bin\Debug\net5.0-windows10.0.18362.0\ColorCode.WinUI.dll' could not be found
6>Done building project "ColorCode.WinUITests.csproj" -- FAILED.
8>------ Build started: Project: ColorCode.WinUITests (Package), Configuration: Debug x64 ------
7>  ColorCode.UWPTests -> C:\Users\Rosario\source\repos\ColorCode-Universal\Tests\ColorCode.UWPTests\bin\x64\Debug\ColorCode.UWPTests.exe
7>C:\Program Files (x86)\Microsoft Visual Studio\2019\Enterprise\MSBuild\Microsoft\VisualStudio\v16.0\AppxPackage\Microsoft.AppXPackage.Targets(826,5): warning : Certificate file does not exist: ColorCode.UWPTests_TemporaryKey.pfx
8>C:\Program Files (x86)\Microsoft Visual Studio\2019\Enterprise\MSBuild\Current\Bin\Microsoft.Common.CurrentVersion.targets(2123,5): warning MSB3277: Found conflicts between different versions of "WinRT.Runtime" that could not be resolved.  These reference conflicts are listed in the build log when log verbosity is set to detailed.
8>C:\Users\Rosario\source\repos\ColorCode-Universal\Tests\ColorCode.WinUITests\ColorCode.WinUITests.csproj : XamlCompiler error WMC1006: Cannot resolve Assembly or Windows Metadata file 'C:\Users\Rosario\source\repos\ColorCode-Universal\ColorCode.WinUI\bin\Debug\net5.0-windows10.0.18362.0\ColorCode.WinUI.dll'
7>C:\Program Files (x86)\Microsoft Visual Studio\2019\Enterprise\MSBuild\Microsoft\VisualStudio\v16.0\AppxPackage\Microsoft.AppXPackage.Targets(2714,5): warning APPX0104: Certificate file 'ColorCode.UWPTests_TemporaryKey.pfx' not found.
7>C:\Program Files (x86)\Microsoft Visual Studio\2019\Enterprise\MSBuild\Microsoft\VisualStudio\v16.0\AppxPackage\Microsoft.AppXPackage.Targets(2714,5): warning APPX0107: The certificate specified is not valid for signing. For more information about valid certificates, see http://go.microsoft.com/fwlink/?LinkID=241478.
8>CSC : error CS0006: Metadata file 'C:\Users\Rosario\source\repos\ColorCode-Universal\ColorCode.WinUI\bin\Debug\net5.0-windows10.0.18362.0\ColorCode.WinUI.dll' could not be found
8>Done building project "ColorCode.WinUITests.csproj" -- FAILED.
========== Build: 5 succeeded, 3 failed, 0 up-to-date, 0 skipped ==========

There is nothing documented as for local development setup so I don't know if there is anything I need to install.

[Rosuavio]

Also I dont know if this is new as of this PR but I got this modal pop up

I never got that prompt or had to install 10.0.16299.0 for building and developing the windows community toolkit, should we up the minimum versions in this project?

[azchohfi]

You need the .NET SDK 5.0.201.
Also, the tests are targeting an older SDK, so just install that one, or raise an issue so we can properly either change this or document this.

[Rosuavio]

Tested, looks good.