WPF下载远程文件，并显示进度条和百分比

1、xaml

 2、CS程序

using System;using System.Windows;using System.Windows.Controls;using System.Net;using System.IO;using System.Threading;using System.Drawing;namespace WpfDemo{    /// 
    /// MainWindow.xaml 的交互逻辑    /// 
    public partial class MainWindow : Window    {        public MainWindow()        {            InitializeComponent();            if (HttpFileExist("http://183.62.138.31:57863/opt/resources/%E9%A3%8E%E6%99%AF/f1.jpg"))            {                DownloadHttpFile("http://183.62.138.31:57863/opt/resources/%E9%A3%8E%E6%99%AF/f1.jpg", @"d:\f1.jpg");            }        }        public void DownloadHttpFile(String http_url, String save_url)        {            WebResponse response = null;            //获取远程文件            WebRequest request = WebRequest.Create(http_url);            response = request.GetResponse();            if (response == null) return;            //读远程文件的大小            pbDown.Maximum = response.ContentLength;            //下载远程文件            ThreadPool.QueueUserWorkItem((obj) =>            {                Stream netStream = response.GetResponseStream();                Stream fileStream = new FileStream(save_url, FileMode.Create);                byte[] read = new byte[1024];                long progressBarValue = 0;                int realReadLen = netStream.Read(read, 0, read.Length);                while (realReadLen > 0)                {                    fileStream.Write(read, 0, realReadLen);                    progressBarValue += realReadLen;                    pbDown.Dispatcher.BeginInvoke(new ProgressBarSetter(SetProgressBar), progressBarValue);                    realReadLen = netStream.Read(read, 0, read.Length);                }                netStream.Close();                fileStream.Close();            }, null);        }                /// 
        ///  判断远程文件是否存在        /// 
        /// 文件URL        /// 
     
      存在-true，不存在-false
             private bool HttpFileExist(string http_file_url)        {            WebResponse response = null;            bool result = false;//下载结果            try            {                response = WebRequest.Create(http_file_url).GetResponse();                result = response == null ? false : true;            }            catch (Exception ex)            {                result = false;            }            finally            {                if (response != null)                {                    response.Close();                }            }            return result;        }        public delegate void ProgressBarSetter(double value);        public void SetProgressBar(double value)        {            //显示进度条            pbDown.Value = value;            //显示百分比            label1.Content = (value / pbDown.Maximum) * 100 + "%";        }    }}