上载进度条的实现

下载进度条的实现
在wpf中添加一自动更新功能，下载功能已实现，但是下载进度条的显示未实现。

XML code

<ProgressBar Name="Prog" Margin="29,72,23,0" Height="27" VerticalAlignment="Top">                    </ProgressBar>

C# code

/// <summary>        /// 下载文件        /// </summary>        /// <param name="filename"></param>        private void DownLoadFile(string URL, string Filename, ProgressBar pm)        {            //WebClient wc = new WebClient();            try            {                //Uri address = new Uri(URL + Filename);                //wc.DownloadFile(address, Filename);                //从URL地址得到一个WEB请求                System.Net.HttpWebRequest Myrq = (System.Net.HttpWebRequest)System.Net.HttpWebRequest.Create(URL + Filename);                //从WEB请求得到WEB响应                 System.Net.HttpWebResponse myrp = (System.Net.HttpWebResponse)Myrq.GetResponse();                //从WEB响应得到总字节数                long totalBytes = myrp.ContentLength;                //从总字节数得到进度条的最大值                pm.Maximum = (int)totalBytes;                //从WEB请求创建流（读）                System.IO.Stream st = myrp.GetResponseStream();                //确定下载文件的路径                string DownLoadPath = @"C:\SalesReport\" + Filename;                //创建文件流（写）                System.IO.Stream so = new System.IO.FileStream(DownLoadPath, System.IO.FileMode.Create);                //下载文件大小                long totalDownloadedByte = 0;                byte[] by = new byte[1024];                //读流                int osize = st.Read(by, 0, (int)by.Length);                while (osize > 0)                {                    //更新文件大小                    totalDownloadedByte = osize + totalDownloadedByte;                    //写流                     so.Write(by, 0, osize);                    //更新进度条                     pm.Value = (int)totalDownloadedByte;                    //读流                    osize = st.Read(by, 0, (int)by.Length);                }                //关闭流                so.Close();                //关闭流                st.Close();            }            catch (Exception ex)            {                throw new Exception("下载更新文件出错：" + ex.Message);            }        }