Dispatcher.BeginInvoke對界面的阻塞作用

XAML代碼：

<Window x:Class="WpfApplication1.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        Title="MainWindow" Height="350" Width="525">
    <Window.Resources>

        <Storyboard x:Key="OnLoaded1" RepeatBehavior="Forever">
            <DoubleAnimationUsingKeyFrames Storyboard.TargetProperty="(Line.X1)">
                <EasingDoubleKeyFrame KeyTime="0" Value="0"/>
                <EasingDoubleKeyFrame KeyTime="0:0:0.5" Value="16"/>
            </DoubleAnimationUsingKeyFrames>
        </Storyboard>
    
        
    </Window.Resources>
    <Grid>
        <Line Height="208" Margin="12,0,0,0" Name="line7" Stroke="Red" StrokeDashArray="3" StrokeDashCap="Triangle" StrokeThickness="3" VerticalAlignment="Bottom" X1="0" X2="500" Y1="3" Y2="3" Canvas.Top="269" Canvas.Left="204" />
    </Grid>
</Window>

c#代碼：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Navigation;
using System.Windows.Shapes;
using System.Windows.Media.Animation;
using System.Threading;

namespace WpfApplication1
{
    /// <summary>
    /// MainWindow.xaml 的交互邏輯
    /// </summary>
    public partial class MainWindow : Window
    {
        public MainWindow()
        {
            InitializeComponent();

            Storyboard Right;
            Right = (Storyboard)this.FindResource("OnLoaded1");
            line7.BeginStoryboard(Right);

            Thread newThread = new Thread(new ThreadStart(ThreadStart));
            newThread.IsBackground = true;
            newThread.Start();

        }

        private void ThreadStart()
        {
          
            int n = 0;
            while (true)
            {
                Thread.Sleep(1000);

                //每5秒鐘調用一次
                n++;
                if (n == 5)
                {
                    n = 0;

                    System.Windows.Application.Current.Dispatcher.BeginInvoke(new Action(delegate
                    {
                        try
                        {
                            Thread.Sleep(1000);
                        }
                        catch (Exception)
                        {
                        }
                    }));

                    
                }
            }
        }
    }
}
 

運行上面這個簡單的demo，發現每隔5秒鐘界面動畫就會卡死1秒。

因此 System.Windows.Application.Current.Dispatcher.BeginInvoke這個語句是會造成界面卡死的，在多線程中慎用這個操作。