WPF刷新界面

Winform 里有 Application.DoEvents();可刷新！

WPF 里没这个，尽管可用委托实现多线程，但是刷新还是不行！

后来找到了 类似App.DoEvents()的方法（）；

代码：

using System;
using System.Collections.Generic;
using System.Configuration;
using System.Data;
using System.Linq;
using System.Windows;

using System.Text;
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.Threading;
using System.Windows.Threading;

namespace wgscd
{

public partial class App : Application
    {
        private static DispatcherOperationCallback exitFrameCallback = new DispatcherOperationCallback(ExitFrame);
        public static void DoEvents()
        {
            DispatcherFrame nestedFrame = new DispatcherFrame();
            DispatcherOperation exitOperation =  Dispatcher.CurrentDispatcher.BeginInvoke (DispatcherPriority.Background, exitFrameCallback, nestedFrame);
            Dispatcher.PushFrame(nestedFrame);
            if (exitOperation.Status !=
            DispatcherOperationStatus.Completed)
            {
                exitOperation.Abort();
            }
        }

private static Object ExitFrame (Object state)
        {
            DispatcherFrame frame = state as
            DispatcherFrame;
            frame.Continue = false;
            return null;
        }

}

}

------------------------------------------------------------------

这样在需要调用刷新的地方就可:App.DoEvents();

-----------------例子--------------------------------------------

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.Threading;
using System.Windows.Threading;

namespace wgscd
{
    /// <summary>
    /// MainWindow.xaml 的交互逻辑
    /// </summary>
    public partial class MainWindow : Window
    {
        public MainWindow()
        {
            InitializeComponent();

myDothread = new DoThread(doJob);
            t.Tick+=new EventHandler(t_Tick);
            t.Interval = TimeSpan.FromMilliseconds( 100d);
            t.Start();

}

int i = 0;
        public delegate void DoThread();
        DoThread myDothread;
        DispatcherTimer t = new DispatcherTimer();//定义一个 定时器
        void t_Tick(object sender ,EventArgs e){

this.Title = DateTime.Now .ToString();
           // textBox1.Text = i.ToString();
        }

private void button1_Click(object sender, RoutedEventArgs e)
        {
            textBox1.Text = "11";
            myDothread.BeginInvoke(null,null );

}

void doJob() {

i = 0;

//System.Windows.Threading.Dispatcher.Run();
         
                DoThread dotd = delegate()
                {

// Thread.Sleep(20000);  //这样就会让 按钮(button1)假死，WPF还是 无能为力吗？

while (i < 33773)
                    {
                        textBox1.Text =i.ToString();
                        i++;
                       // textBox1.UpdateLayout();
                        App.DoEvents();//这里可刷新文本框！
                   
                    }

};
        
           this.Dispatcher.BeginInvoke(dotd,null);

}

private void button2_Click(object sender, RoutedEventArgs e)
        {
            textBox1.Text = "hello";
        }

}
}

//--------------------------------------------------------------------------------------------------------

WPF多线程改变界面元素

第1种用 Task类. 推荐用这个办法

publicvoid工作_Task()
{
Dispatcher x=Dispatcher.CurrentDispatcher;//取得当前工作线程
//另开线程工作
Task<int>计数=newTask<int>(()=>{return计数方法(); });
计数.ContinueWith(工作完毕后方法);//工作完毕后执行的方法
计数.Start();//开始工作

}
publicvoid工作完毕后方法(Task<int>参数)
{
if(参数.IsCompleted)//正常工作完毕
{
var 结果=参数.Result;//取得结果
//处理结果.
//本方法非界面线程.如果需要在界面线程操作,需要转移到界面线程
}
}

intc;
publicint计数方法()
{
returnc++;
}

第2种方法用线程

publicvoid工作_Thread()
{
Dispatcher x=Dispatcher.CurrentDispatcher;//取得当前工作线程
//另开线程工作
System.Threading.ThreadStart start=delegate()
{
//工作函数
Func<string>fu=newFunc<string>(()=>{return""; });//工作函数
var 工作结果=fu();//开始工作

//异步更新界面
x.BeginInvoke(newAction(()=>
{
//在界面线程操作 可以使用 工作结果
}), DispatcherPriority.Normal); 
};
newSystem.Threading.Thread(start).Start();//启动线程
}

第3种方法用 BackgroundWorker.

BackgroundWorker 后台线程;
publicvoid线程初始化()
{
后台线程=newBackgroundWorker();
后台线程.WorkerSupportsCancellation=true;//可以取消
后台线程.DoWork+=newDoWorkEventHandler(后台线程_DoWork);
后台线程.RunWorkerCompleted+=newRunWorkerCompletedEventHandler(后台线程_RunWorkerCompleted); 
}
publicvoid启动后台线程()
{
后台线程.RunWorkerAsync();
}

void后台线程_RunWorkerCompleted(objectsender, RunWorkerCompletedEventArgs e)
{
//工作完毕的方法
}

void后台线程_DoWork(objectsender, DoWorkEventArgs e)
{
//工作方法
}