A simple WPF Window whose controls, styles, triggers, event, etc. are written in code-behind only

MainWindow.xaml

<Window ...>
    <Window.Resources>
        <local:BrightnessToBoolConverter x:Key="conv" />
        <Style TargetType="Button">
            <Setter Property="FontSize" Value="16" />
            <Setter Property="Foreground" Value="Black" />
            <Setter Property="FocusVisualStyle" Value="{x:Null}" />
            <EventSetter Event="Click" Handler="OnButtonClicked" />
            <Style.Triggers>
                <DataTrigger Binding="{Binding RelativeSource={RelativeSource Self}, Path=Background, Converter={StaticResource conv}}" Value="False">
                    <Setter Property="Foreground" Value="White" />
                </DataTrigger>
            </Style.Triggers>
        </Style>
    </Window.Resources>
</Window>

MainWindow.xaml.cs

using System;
using System.Globalization;
using System.Linq;
using System.Reflection;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Media;

namespace BuiltInBrushesViewer;

public partial class MainWindow : Window
{
    public MainWindow()
    {
        InitializeComponent();

        this.Loaded += OnLoaded;
    }

    private void OnLoaded(object sender, RoutedEventArgs e)
    {
        var panel = new VirtualizingStackPanel();

        typeof(Brushes)
            .GetProperties(BindingFlags.Public | BindingFlags.Static)
            .ToList()
            .ForEach(prop =>
            {
                var brush = (SolidColorBrush)prop.GetValue(null)!;
                var btn = new Button
                {
                    Background = brush,
                    Content = prop.Name,
                    Style = GetButtonStyle()
                };
                panel.Children.Add(btn);
            });

        this.Content = new ScrollViewer
        {
            HorizontalScrollBarVisibility = ScrollBarVisibility.Disabled,
            Content = panel
        };
    }

    /// <summary>
    /// 创建一个 <see cref="Button"/> 的样式
    /// </summary>
    public Style GetButtonStyle()
    {
        Style style = new Style(typeof(Button));

        // FontSize 的 value 不能写 16，因为是整数，不符合 FontSize 属性的要求（这里不会自动转换类型）
        style.Setters.Add(new Setter(Button.FontSizeProperty, 16.0));
        style.Setters.Add(new Setter(Button.ForegroundProperty, Brushes.Black));
        style.Setters.Add(new Setter(Button.FocusVisualStyleProperty, null));

        // Handler 不能直接写 lambda 表达式，会报 ArgumentException，需要外面套一层 RoutedEventHandler
        style.Setters.Add(new EventSetter(Button.ClickEvent, new RoutedEventHandler((object sender, RoutedEventArgs e) =>
        {
            if (sender is not Button btn) return;
            Clipboard.SetText((string)btn.Content);
        })));

        // 添加一个 DataTrigger
        DataTrigger foregroundTrigger = new DataTrigger
        {
            Binding = new Binding
            {
                Path = new PropertyPath("Background"),
                RelativeSource = RelativeSource.Self,
                Converter = new BrightnessToBoolConverter()
            },
            Value = false
        };
        foregroundTrigger.Setters.Add(new Setter(Button.ForegroundProperty, Brushes.White));
        style.Triggers.Add(foregroundTrigger);

        return style;
    }
}

public class BrightnessToBoolConverter : IValueConverter
{
    public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
    {
        if (value is not SolidColorBrush b)
            throw new ArgumentException(nameof(value));
        int color = (b.Color.R + b.Color.G + b.Color.B) / 3;
        return color >= 127;
    }

    public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture)
    {
        throw new NotImplementedException();
    }
}