Enable the ability to include default styles alongside Maui Controls

[PureWeen]

Currently there's not a reasonable way to package default styles inside Controls. If we try to add our own DefaultDictionary into Merged Dictionary it gets cleared out after InitalizeComponent is called.

At a later point I'll elaborate on the spec here but the ideal end goal here would be

• The ability to package XAML based themes with Controls
• The ability to define the concept of Defaults for controls stylings that feed from our themes.
• We recently added default styles into our templates. Ideally we'd be able to feed our control defaults off these colors. We would have the same idea as "AccentColor" etc.. that would act as defaults for colors that users could define to achieve consistent theming

https://github.com/dotnet/maui/pull/6255

[SchreinerK]

does v7 then include something like the assignment of the default style in WPF?

static CustomControl() {
    DefaultStyleKeyProperty.OverrideMetadata(typeof(CustomControl), new FrameworkPropertyMetadata(typeof(CustomControl)));
}

or is there another way to create custom control libraries?

[ghost]

We've moved this issue to the Backlog milestone. This means that it is not going to be worked on for the coming release. We will reassess the backlog following the current release and consider this item at that time. To learn more about our issue management process and to have better expectation regarding different types of issues you can read our Triage Process.

[Alex-Dobrynin]

+1 UP

[japarson]

@StephaneDelcroix FYI running into this issue when trying to convert a WPF LPE unit test to work for MAUI.