<UserControl x:Class="CustomControls.MyUserControl"
             xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
             Height="100" Width="100">
    <Grid>
        <Button Content="Click Me" Name="btnClickMe"/>
    </Grid>
</UserControl>

public partial class MyUserControl : UserControl
{
    public MyUserControl()
    {
        InitializeComponent();
        btnClickMe.Click += BtnClickMe_Click;
    }

    private void BtnClickMe_Click(object sender, RoutedEventArgs e)
    {
        MessageBox.Show("UserControl Button Clicked");
    }
}

public class ClickCountButton : Button
{
    public int ClickCount { get; private set; }

    protected override void OnClick()
    {
        base.OnClick();
        ClickCount++;
    }
}

public class CircularControl : Control
{
    static CircularControl()
    {
        DefaultStyleKeyProperty.OverrideMetadata(typeof(CircularControl), 
            new FrameworkPropertyMetadata(typeof(CircularControl)));
    }

    public double Radius
    {
        get { return (double)GetValue(RadiusProperty); }
        set { SetValue(RadiusProperty, value); }
    }

    public static readonly DependencyProperty RadiusProperty =
        DependencyProperty.Register("Radius", typeof(double), typeof(CircularControl), 
            new PropertyMetadata(50.0, OnRadiusChanged));

    private static void OnRadiusChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
    {
        // Handle property changed logic
    }
}

<Style TargetType="{x:Type local:CircularControl}">
    <Setter Property="Template">
        <Setter.Value>
            <ControlTemplate TargetType="{x:Type local:CircularControl}">
                <Grid>
                    <Ellipse Width="{TemplateBinding Radius}" Height="{TemplateBinding Radius}" 
                             Fill="LightBlue"/>
                </Grid>
            </ControlTemplate>
        </Setter.Value>
    </Setter>
</Style>

public static class FocusExtension
{
    public static bool GetIsFocused(DependencyObject obj)
    {
        return (bool)obj.GetValue(IsFocusedProperty);
    }

    public static void SetIsFocused(DependencyObject obj, bool value)
    {
        obj.SetValue(IsFocusedProperty, value);
    }

    public static readonly DependencyProperty IsFocusedProperty =
        DependencyProperty.RegisterAttached(
            "IsFocused", 
            typeof(bool), 
            typeof(FocusExtension), 
            new UIPropertyMetadata(false, OnIsFocusedPropertyChanged));

    private static void OnIsFocusedPropertyChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
    {
        var uie = (UIElement)d;
        if ((bool)e.NewValue)
        {
            uie.Focus(); // Call Focus if true
        }
    }
}

public class HighlightBehavior : Behavior<TextBox>
{
    protected override void OnAttached()
    {
        base.OnAttached();
        AssociatedObject.GotFocus += OnGotFocus;
        AssociatedObject.LostFocus += OnLostFocus;
    }

    protected override void OnDetaching()
    {
        base.OnDetaching();
        AssociatedObject.GotFocus -= OnGotFocus;
        AssociatedObject.LostFocus -= OnLostFocus;
    }

    private void OnGotFocus(object sender, RoutedEventArgs e)
    {
        AssociatedObject.Background = new SolidColorBrush(Colors.LightYellow);
    }

    private void OnLostFocus(object sender, RoutedEventArgs e)
    {
        AssociatedObject.Background = new SolidColorBrush(Colors.White);
    }
}

print("擁抱新技術(shù)才是王道！")