如何制作简单的WPF时钟

// 时钟控件类：Clock.cs
using System;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Controls.Primitives;
using System.Windows.Data;
using System.Windows.Documents;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Shapes;
using System.Timers;
using System.Windows.Threading;
namespace BrawDraw.Com.WPF.Clock.ControlLibrary
{
/// <summary>Clock Control
/// </summary>
public class Clock : Control
{
private DispatcherTimer timer;
static Clock()
{
DefaultStyleKeyProperty.OverrideMetadata(typeof(Clock), 
new FrameworkPropertyMetadata(typeof(Clock)));
}
protected override void OnInitialized(EventArgs e)
{
base.OnInitialized(e);
timer = new DispatcherTimer();
timer.Tick += new EventHandler(Timer_Tick);
timer.Start();
  }
private void Timer_Tick(object sender, EventArgs e)
{
UpdateDateTime();
timer.Interval = TimeSpan.FromMilliseconds(1000 - 
DateTime.Now.Millisecond);
}
private void UpdateDateTime()
{
this.DateTime = System.DateTime.Now;
}
#region DateTime property
public DateTime DateTime
{
get
{
return (DateTime)GetValue(DateTimeProperty);
}
private set
{
SetValue(DateTimeProperty, value);
}
}
public static DependencyProperty DateTimeProperty = 
DependencyProperty.Register(
"DateTime",
typeof(DateTime),
typeof(Clock),
new PropertyMetadata(DateTime.Now, 
new PropertyChangedCallback(OnDateTimeInvalidated)));
public static readonly RoutedEvent DateTimeChangedEvent =
EventManager.RegisterRoutedEvent("DateTimeChanged", 
RoutingStrategy.Bubble, typeof(RoutedPropertyChangedEventHandler<DateTime>), 
typeof(Clock));
protected virtual void OnDateTimeChanged(DateTime oldValue, 
DateTime newValue)
{
RoutedPropertyChangedEventArgs<DateTime> args = 
new RoutedPropertyChangedEventArgs<DateTime>(oldValue, newValue);
args.RoutedEvent = Clock.DateTimeChangedEvent;
RaiseEvent(args);
}
private static void OnDateTimeInvalidated(DependencyObject d, 
DependencyPropertyChangedEventArgs e)
{
Clock clock = (Clock)d;
DateTime oldValue = (DateTime)e.OldValue;
DateTime newValue = (DateTime)e.NewValue;
clock.OnDateTimeChanged(oldValue, newValue);
}
#endregion
}
}
// 时钟内部时针、分针、秒针角度计算及星期显示的类： ClockConverters.cs
// 由于WPF中旋转角度是以度单位，计算为绕一个圆周时，为360度。所以，计算时以360度来计算。
using System;
using System.Globalization;
using System.Windows.Data;
namespace BrawDraw.Com.WPF.Clock
{
// 一分钟60秒，一周为360度，所以，一秒钟就占6度，所以是：秒数×6。
[ValueConversion(typeof(DateTime), typeof(int))]
public class SecondsConverter : IValueConverter
{
public object Convert(object value, Type targetType, object parameter, 
CultureInfo culture)
{
DateTime date = (DateTime)value;
return date.Second * 6;
}
public object ConvertBack(object value, Type targetType, object parameter, 
CultureInfo culture)
{
return null;
}
}
// 一小时是60分钟，一周为360度，所以，一分钟就占6度，所以是：分钟数×6。
[ValueConversion(typeof(DateTime), typeof(int))]
public class MinutesConverter : IValueConverter
{
public object Convert(object value, Type targetType, 
object parameter, CultureInfo culture)
{
DateTime date = (DateTime)value;
return date.Minute * 6;
}
public object ConvertBack(object value, Type targetType, 
object parameter, CultureInfo culture)
{
return null;
}
}
// 时钟上显示12小时，一周为360度，这样，每小时占30度，考虑分钟所占角度是分钟数/2，
       所以结果是：小时数×30 + 分钟数/2。
    [ValueConversion(typeof(DateTime), typeof(int))]
public class HoursConverter : IValueConverter
{
public object Convert(object value, Type targetType, 
object parameter, CultureInfo culture)
{
DateTime date = (DateTime)value;
return (date.Hour * 30) + (date.Minute / 2);
}
public object ConvertBack(object value, Type targetType, 
object parameter, CultureInfo culture)
{
return null;
}
}
[ValueConversion(typeof(DateTime), typeof(string))]
public class WeekdayConverter : IValueConverter
{
public object Convert(object value, Type targetType, 
object parameter, CultureInfo culture)
{
DateTime date = (DateTime)value;
return date.DayOfWeek.ToString().Substring(0,3);
}
public object ConvertBack(object value, Type targetType, 
object parameter, CultureInfo culture)
{
return null;
}
}
}