YZWater3/src/YZWater.Avalonia/Views/ViewDView.axaml.cs

using Avalonia.Controls;
using Avalonia.VisualTree;
using YZWater.Avalonia.Controls;

namespace YZWater.Avalonia.Views;

public partial class ViewDView : UserControl
{
    private Border? _titleBar;
    private Border? _statusBar;
    private Border? _rootBorder;
    private TextBlock? _titleText;
    private TextBlock? _subtitleText;

    public ViewDView()
    {
        InitializeComponent();
        AttachedToVisualTree += (_, _) =>
        {
            FindElements();
            ApplyTheme();
            ThemeHelper.ThemeChanged += ApplyTheme;
        };
        DetachedFromVisualTree += (_, _) =>
        {
            ThemeHelper.ThemeChanged -= ApplyTheme;
        };
    }

    private void FindElements()
    {
        foreach (var v in this.GetVisualDescendants())
        {
            if (v is Border b)
            {
                if (b.Name == "TitleBar") _titleBar = b;
                else if (b.Name == "StatusBar") _statusBar = b;
                else if (b.Name == "RootBorder") _rootBorder = b;
            }
            else if (v is TextBlock tb)
            {
                if (tb.Name == "TitleText") _titleText = tb;
                else if (tb.Name == "SubtitleText") _subtitleText = tb;
            }
        }
    }

    private void ApplyTheme()
    {
        if (_titleBar != null) _titleBar.Background = ThemeHelper.HeaderBg;
        if (_statusBar != null) _statusBar.Background = ThemeHelper.NavBg;
        if (_rootBorder != null) _rootBorder.Background = ThemeHelper.AppBg;
        if (_titleText != null) _titleText.Foreground = ThemeHelper.HeaderText;
        if (_subtitleText != null) _subtitleText.Foreground = ThemeHelper.HeaderSubtext;
    }
}