SettingsViewModel.cs

using System.Windows.Input;
using CommunityToolkit.Mvvm.ComponentModel;
using CommunityToolkit.Mvvm.Input;
using Vereinsmeisterschaften.Contracts.Services;
using Vereinsmeisterschaften.Contracts.ViewModels;
using Vereinsmeisterschaften.Models;
 
namespace Vereinsmeisterschaften.ViewModels;

public partial class SettingsViewModel : ObservableObject, INavigationAware
{
    [ObservableProperty]
    private AppTheme _theme;
    
    private ICommand _setThemeCommand;
    public ICommand SetThemeCommand => _setThemeCommand ?? (_setThemeCommand = new RelayCommand<string>(OnSetTheme));
 
    private readonly IThemeSelectorService _themeSelectorService;

    public SettingsViewModel(IThemeSelectorService themeSelectorService)
    {
        _themeSelectorService = themeSelectorService;
    }

    public void OnNavigatedTo(object parameter)
    {
        Theme = _themeSelectorService.GetCurrentTheme();
    }

    public void OnNavigatedFrom()
    {
    }
 
    private void OnSetTheme(string themeName)
    {
        var theme = (AppTheme)Enum.Parse(typeof(AppTheme), themeName);
        _themeSelectorService.SetTheme(theme);
    }
}