Convert various DirectProperty definitions to StyledProperty

[TomEdwardsEnscape]

What does the pull request do?

This is the first change which directly addresses #9944, the end goal of which is to avoid public DirectProperty setters on types which derive from StyledElement.

What is the current behavior?

See #9944.

What is the updated/expected behavior with this PR?

This PR refactors a large batch of properties from DirectProperty to StyledProperty. The new SetCurrentValue method is now used to set the value of refactored properties, where necessary.

Only properties which could be easily changed are included. Properties with complicated behaviours will be handled in smaller PRs.

There are some additional changes:

• In a few cases, a DirectProperty was not changed to StyledProperty, but instead had its setter removed. StyledElement.TemplatedParent is a notable example: the CLR property has an internal setter, but this could be evaded by calling SetValue(TemplatedParentProperty). Closing backdoors like these reduces Avalonia's API surface.
• TemplateBinding now uses SetCurrentValue.
• The various property AddOwner methods now accept a metadata object, mirroring WPF's API.
• ComboBox.SelectionBoxItem has been changed from a protected property to a public property with a protected setter. This better reflects the accessibility of the DirectProperty it wraps around.
• Button.IsPressed has been changed to a read-only DirectProperty, and an old test that tried to data bind to it has been removed.

Breaking changes

• The refactored properties now function with binding priorities. This means that when a value source is removed, the property now reverts to a different value source (or the default value). Anyone who relied on the old, broken behaviour of the value remaining unchanged in this scenario will have to refactor their code.
• Anyone who calls AddOwner on a refactored property will have to refactor their controls to match the new property type.
• Anyone sneakily calling internal C# property setters with the incorrectly-exposed DirectProperty setters that this PR removes will have to stop hacking Avalonia. 🤡

Obsoletions / Deprecations

None

Fixed issues

Part of #9944

[avaloniaui-team]

You can test this PR using the following package version. 11.0.999-cibuild0030143-beta. (feed url: https://pkgs.dev.azure.com/AvaloniaUI/AvaloniaUI/_packaging/avalonia-all/nuget/v3/index.json) [PRBUILDID]

[avaloniaui-team]

You can test this PR using the following package version. 11.0.999-cibuild0030367-beta. (feed url: https://pkgs.dev.azure.com/AvaloniaUI/AvaloniaUI/_packaging/avalonia-all/nuget/v3/index.json) [PRBUILDID]

[avaloniaui-team]

You can test this PR using the following package version. 11.0.999-cibuild0030465-beta. (feed url: https://pkgs.dev.azure.com/AvaloniaUI/AvaloniaUI/_packaging/avalonia-all/nuget/v3/index.json) [PRBUILDID]

[grokys]

Looks like Avalonia.IntegrationTests.Appium.CheckBoxTests.UncheckedCheckBox is broken after these changes.

[TomEdwardsEnscape]

I was hoping that would prove to be a temporary glitch, but it apparently is not. Is there a guide somewhere for setting up Appium locally?

[robloo]

@tomenscape Looks like the best guide is the Readme under tests/Avalonia.IntegrationTests.Appium.

ToggleButton changes are likely the root. However, the only thing I see that could be wrong is SetCurrentValue(). Otherwise, there is an extension method GetIsChecked() in ElementExtensions.cs which might be the issue. Honestly not sure how this works to begin with though.

[grokys]

It does indeed look like checkboxes are broken ;)

3MvZNjMR4s.mp4

[robloo]

Well, that's interesting. However, it might be an issue with SetCurrentValue() and derived controls. It looks similar to the ColorPicker issues as well.

[grokys]

Yeah, I don't have time to investigate last night. Will try to work out what's happening if no-one else gets there first :)

[grokys]

Another problem I've noticed: inspecting a control in DevTools breaks the margin on certain controls:

tFmW4aZ3s3.mp4

Probably caused by the change to ThicknessEditor: might it make sense to revert the changes to internal properties for the moment so we have less to deal with? We can easily change them to styled properties in future.

[grokys]

However, it might be an issue with SetCurrentValue()

Yep, looks like SetCurrentValue has problems, this will need a fix.

[grokys]

Opened #10497 with a fix.

[TomEdwardsEnscape]

That PR also fixes the ThicknessEditor problem.

[avaloniaui-team]

You can test this PR using the following package version. 11.0.999-cibuild0030836-beta. (feed url: https://pkgs.dev.azure.com/AvaloniaUI/AvaloniaUI/_packaging/avalonia-all/nuget/v3/index.json) [PRBUILDID]

[grokys]

Apologies for the delay on this, PRs are being help up by problems with our CI. Waiting for the SetCurrentValue fix to hit master and will re-run the integration tests.

[avaloniaui-team]

You can test this PR using the following package version. 11.0.999-cibuild0031073-beta. (feed url: https://pkgs.dev.azure.com/AvaloniaUI/AvaloniaUI/_packaging/avalonia-all/nuget/v3/index.json) [PRBUILDID]

[grokys]

All unit and integration tests now passing, did a manual test with ControlCatalog and didn't see any problems so I say we're ready to go!

[grokys]

Oh wait, I just took a final look and it seems like non-Control properties are still converted to StyledProperty. In the comment in #10370 (comment) I meant that I think we should remove these changes for now, as

1. They can't really be styled anyway
2. Some of the properties are collection types, which are problematic in combination with styling currently (see below)

[avaloniaui-team]

You can test this PR using the following package version. 11.0.999-cibuild0031120-beta. (feed url: https://pkgs.dev.azure.com/AvaloniaUI/AvaloniaUI/_packaging/avalonia-all/nuget/v3/index.json) [PRBUILDID]