C# 带进度条的文件下载

 private long fileLength;

 private long downLength;//已经下载文件大小，外面想用就改成公共属性 

 private static bool stopDown;

 public HttpDownLoad()

 {

     fileLength = ;

     downLength = ;

     stopDown = false;

     // 

     //   TODO:   在此处添加构造函数逻辑 

     // 

 }

 ///   <summary> 

 ///   文件下载 

 ///   </summary> 

 ///   <param   name= "url "> 连接 </param> 

 ///   <param   name= "fileName "> 本地保存文件名 </param> 

 ///   <param   name= "progressBar "> 进度条 </param> 

 public void httpDownFile(string url, string fileName, ProgressBar progressBar)

 {

     Label lable = new Label();

     httpDownFile(url, fileName, progressBar, lable);

     lable.Dispose();

 }

 ///   <summary> 

 ///   文件下载 

 ///   </summary> 

 ///   <param   name= "url "> 连接 </param> 

 ///   <param   name= "fileName "> 本地保存文件名 </param> 

 ///   <param   name= "progressBar "> 进度条 </param> 

 ///   <param   name= "label "> 返回已经下载的百分比 </param> 

 public string httpDownFile(string url, string fileName, ProgressBar progressBar, Label label)

 {

     string strState = "No";

     stopDown = false;

     Stream str = null, fs = null;

     try

     {

         //获取下载文件长度 

         fileLength = getDownLength(url);

         downLength = ;

         if (fileLength > )

         {

             WebClient DownFile = new WebClient();

             str = DownFile.OpenRead(url);

             //判断并建立文件 

             if (createFile(fileName))

             {

                 byte[] mbyte = new byte[];

                 int readL = str.Read(mbyte, , );

                 fs = new FileStream(fileName, FileMode.OpenOrCreate, FileAccess.Write);

                 //读取流 

                 while (readL != )

                 {

                     if (stopDown)

                         break;

                     downLength += readL;//已经下载大小 

                     fs.Write(mbyte, , readL);//写文件 

                     readL = str.Read(mbyte, , );//读流 

                     progressBar.Value = (int)(downLength *  / fileLength);

                     label.Text = progressBar.Value.ToString() + "% ";

                     Application.DoEvents();

                     strState = "OK";

                 }

                 str.Close();

                 fs.Close();

             }

         }

     }

     catch (Exception)

     {

         if (str != null)

             str.Close();

         if (fs != null)

             fs.Close();

     }

     return strState;

 }

 ///   <summary> 

 ///   文件下载 

 ///   </summary> 

 ///   <param   name= "url "> 连接 </param> 

 ///   <param   name= "fileName "> 本地保存文件名 </param> 

 public void httpDownFile(string url, string fileName)

 {

     try

     {

         WebClient DownFile = new WebClient();

         DownFile.DownloadFile(url, fileName);

     }

     catch (Exception)

     {

         //MessageBox.Show(ex.Message);

     }

 }

 ///   <summary> 

 ///   获取下载文件大小 

 ///   </summary> 

 ///   <param   name= "url "> 连接 </param> 

 ///   <returns> 文件长度 </returns> 

 private long getDownLength(string url)

 {

     try

     {

         WebRequest wrq = WebRequest.Create(url);

         WebResponse wrp = (WebResponse)wrq.GetResponse();

         wrp.Close();

         return wrp.ContentLength;

     }

     catch (Exception)

     {

         //MessageBox.Show(ex.Message);

         return ;

     }

 }

 ///   <summary> 

 ///   建立文件(文件如已经存在，删除重建) 

 ///   </summary> 

 ///   <param   name= "fileName "> 文件全名(包括保存目录) </param> 

 ///   <returns> </returns> 

 private bool createFile(string fileName)

 {

     try

     {

         if (File.Exists(fileName))

         {

             File.Delete(fileName);

         }

         Stream s = File.Create(fileName);

         s.Close();

         return true;

     }

     catch (Exception)

     {

         //MessageBox.Show(ex.Message);

         return false;

     }

 }

 public void downClose()

 {

     stopDown = true;
 }