WPF刷新界面

Winform 里有 Application.DoEvents();可刷新！

WPF 里沒這個，盡管可用委托實現多線程，但是刷新還是不行！

后來找到了 類似App.DoEvents()的方法（）；

代碼：

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;
        }

    }

 

}

 

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

這樣在需要調用刷新的地方就可: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 的交互邏輯
    /// </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();//定義一個 定時器
        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);  //這樣就會讓 按鈕(button1)假死，WPF還是 無能為力嗎？

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

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

        }

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

 

 

    }
}

 

 

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

WPF多線程改變界面元素

 

第1種用 Task類. 推薦用這個辦法

publicvoid工作_Task()
{
Dispatcher x=Dispatcher.CurrentDispatcher;//取得當前工作線程
//另開線程工作
Task<int>計數=newTask<int>(()=>{return計數方法(); });
計數.ContinueWith(工作完畢后方法);//工作完畢后執行的方法
計數.Start();//開始工作

}
publicvoid工作完畢后方法(Task<int>參數)
{
if(參數.IsCompleted)//正常工作完畢
{
var 結果=參數.Result;//取得結果
//處理結果.
//本方法非界面線程.如果需要在界面線程操作,需要轉移到界面線程
}
}

intc;
publicint計數方法()
{
returnc++;
}

第2種方法用線程

publicvoid工作_Thread()
{
Dispatcher x=Dispatcher.CurrentDispatcher;//取得當前工作線程
//另開線程工作
System.Threading.ThreadStart start=delegate()
{
//工作函數
Func<string>fu=newFunc<string>(()=>{return""; });//工作函數
var 工作結果=fu();//開始工作

//異步更新界面
x.BeginInvoke(newAction(()=>
{
//在界面線程操作 可以使用 工作結果
}), DispatcherPriority.Normal); 
};
newSystem.Threading.Thread(start).Start();//啟動線程
}

第3種方法用 BackgroundWorker.

BackgroundWorker 后台線程;
publicvoid線程初始化()
{
后台線程=newBackgroundWorker();
后台線程.WorkerSupportsCancellation=true;//可以取消
后台線程.DoWork+=newDoWorkEventHandler(后台線程_DoWork);
后台線程.RunWorkerCompleted+=newRunWorkerCompletedEventHandler(后台線程_RunWorkerCompleted); 
}
publicvoid啟動后台線程()
{
后台線程.RunWorkerAsync();
}

void后台線程_RunWorkerCompleted(objectsender, RunWorkerCompletedEventArgs e)
{
//工作完畢的方法
}

void后台線程_DoWork(objectsender, DoWorkEventArgs e)
{
//工作方法
}