BackgroundWorker功能类似于多线程,可以执行耗时操作而不影响UI,用法类似于WebClient,以事件的形式与UI线程通讯,如进度改变,执行完毕。BackgroundWorker还可以在执行过程中取消。范例效果图: 代码:
using System;
using System.Collections.Generic;
using System.Linq;
using System.Net;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Animation;
using System.Windows.Shapes;
using Microsoft.Phone.Controls;
using System.Threading;
using System.ComponentModel;
using System.Diagnostics;
namespace PhoneApp1
{
public partial class MainPage : PhoneApplicationPage
{
private BackgroundWorker bw;
public MainPage()
{
InitializeComponent();
bw = new BackgroundWorker();
bw.WorkerReportsProgress = true;
bw.WorkerSupportsCancellation = true;
bw.DoWork += new DoWorkEventHandler(bw_DoWork);
//后台执行方法
bw.ProgressChanged += new ProgressChangedEventHandler(bw_ProgressChanged);
//进度改变方法
bw.RunWorkerCompleted += new RunWorkerCompletedEventHandler(bw_RunWorkerCompleted);
//事件处理不能在点击按钮时才添加,因为是+=,所以当按钮被点多次时,就会有多个事件处理方法
}
private void button1_Click(object sender, RoutedEventArgs e)
{
if (bw.IsBusy != true)
{//判断是否繁忙,防止在一次没有执行完时按第二次
bw.RunWorkerAsync();
}
}
private void bw_DoWork(object sender,DoWorkEventArgs e)
{//后台执行
BackgroundWorker worker = sender as BackgroundWorker;
for (int i = 1; i <= 10; i++)
{
if ((worker.CancellationPending == true))
{//被取消
e.Cancel = true;
break;
}
else
{
System.Threading.Thread.Sleep(500);
worker.ReportProgress(i * 10);
}
}
}
private void bw_ProgressChanged(object sender, ProgressChangedEventArgs e)
{//更新进度
progressBar1.Value = e.ProgressPercentage;
textBlock1.Text = e.ProgressPercentage.ToString() + "%";
}
private void bw_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e)
{//执行完毕或取消
if (e.Cancelled)
{//判断被取消还是执行完
textBlock1.Text = "被取消";
}
else
{
textBlock1.Text = "执行完毕";
}
}
private void button2_Click(object sender, RoutedEventArgs e)
{//取消执行
if (bw.WorkerSupportsCancellation == true)
{
bw.CancelAsync();
}
}
}
}