Theme Mode

[helladen]

Is your feature request related to a problem? Please describe.
I want a more updated WPF theme, based on the .NET ThemeMode. I tried to make it work with old .NET but it doesn't allow me to use the App.xaml or App.xaml.cs with Eto Forms Application UIKit.

Describe the solution you'd like
ThemeMode WPF .NET 9.0. https://learn.microsoft.com/en-us/dotnet/desktop/wpf/whats-new/net90

Describe alternatives you've considered
Customizing styles is a lot of work to make anything look remotely good. Tried to use other WPF theme engines, but I would love if we could make WPF theme system support other UIKits like Material.

Additional context
Just a better WIndows experience, please. :)

[ris-work]

Even styling WPF is relatively easy for smaller tasks, but it is easy to get lost in the ControlDictionary and other things. WPF with rounded corners, etc. have been harder to me. I also wish we had a better way to handle these (e.g. Rounded controls on all platforms) but it just looks like it is hard.

I also wanted to use the ThemeMode but opted to use do my own theming later (which would work on all platforms) as it became increasingly harder. It is also easier to mess up with XAML files, their order, hierarchy, etc.

[helladen]

So it looks like .NET 9 and .NET 10 both ship with fluent controls that work with Eto Forms WPF backend.

[cwensley]

Thanks for the input @helladen. I do have an open PR here #2735 to add theme APIs to Eto that would expose those. Last I tried (with .NET 9), it still had a long way to go. I am hopeful that in .NET 10 it is more complete/usable.