WPF画布实时刷新的2种方法

        WPF项目上，需要在Canvas上重复的画图，并将每次的图保存起来。画倒是没什么，但发现过程中窗体一直处于空白状态，直到结束Canvas上才显示内容。网上找了些资料，也还是没搞定，反正大概知道是线程间的交互问题。最后，终于找到了2种解决的办法，写了个例子收集下来，以后反正用的到。例子很简单，也就在主窗体上放一个Canvas和一个Button，点击Button会刷新10次画布。

MainWindow.xaml主界面代码

    <Grid>        <Canvas Height="232" HorizontalAlignment="Left" Margin="12,12,0,0" Name="canvas1" VerticalAlignment="Top" Width="467"></Canvas>        <Button Content="Button" Height="23" Name="button1" Width="75" Click="button1_Click" Margin="12,265,416,23" />    </Grid>

MainWindow.xaml.cs后台代码

第一种实现

    public partial class MainWindow : Window    {        public MainWindow()        {            InitializeComponent();        }        private void button1_Click(object sender, RoutedEventArgs e)        {             for (int i = 0; i < 10; i++)            {                if (i % 2 == 0)                {                    Ellipse el = new Ellipse();                    el.Height = 30;                    el.Width = 60;                    el.Fill = Brushes.Red;                    el.Stroke = Brushes.Black;                    canvas1.Children.Add(el);                }                 else                {                    Ellipse el = new Ellipse();                    el.Height = 30;                    el.Width = 60;                    el.Fill = Brushes.Yellow;                    el.Stroke = Brushes.Green;                    canvas1.Children.Add(el);                }                                    System.Threading.Thread.Sleep(1000);                    DispatcherHelper.DoEvents();            }        }     }    public static class DispatcherHelper    {        [SecurityPermissionAttribute(SecurityAction.Demand, Flags = SecurityPermissionFlag.UnmanagedCode)]        public static void DoEvents()        {            DispatcherFrame frame = new DispatcherFrame();            Dispatcher.CurrentDispatcher.BeginInvoke(DispatcherPriority.Background, new DispatcherOperationCallback(ExitFrames), frame);            try { Dispatcher.PushFrame(frame); }            catch (InvalidOperationException) { }        }        private static object ExitFrames(object frame)        {            ((DispatcherFrame)frame).Continue = false;            return null;        }    } 

第二种实现

    public partial class MainWindow : Window    {        public MainWindow()        {            InitializeComponent();        }        private void button1_Click(object sender, RoutedEventArgs e)        {            Thread anotherThread = new Thread(() =>            {                for (int i = 0; i < 10; i++)                {                    canvas1.Dispatcher.BeginInvoke((Action)(() =>                    {                        canvas1.Children.Add(new Ellipse                        {                            Height = 30,                            Width = 60,                            Fill = i % 2 == 0 ? Brushes.Red : Brushes.Yellow,                            Stroke = i % 2 == 0 ? Brushes.Black : Brushes.Green                        });                    }));                    Thread.Sleep(1000);                }            });            anotherThread.SetApartmentState(ApartmentState.STA);            anotherThread.Start();        }    }