C# Winform下载文件并显示进度条

本来是要研究怎样判断下载完成，结果找到这个方法，可以在这个方法完成之后提示下载完成。

代码如下：

 
  using 
   System;
 
  using 
   System.Collections.Generic;
 
  using 
   System.ComponentModel;
 
  using 
   System.Data;
 
  using 
   System.Drawing;
 
  using 
   System.Linq;
 
  using 
   System.Text;
 
  using 
   System.Windows.Forms;

 
  namespace 
   WinShowDown
{
     
  public 
    
  partial 
    
  class 
   FrmMain : Form
    {
         
  public 
   FrmMain()
        {
            InitializeComponent();
        }

         
  private 
    
  void 
   btnDown_Click( 
  object 
   sender, EventArgs e)
        {
            DownloadFile( 
  " 
  http://localhost:1928/WebServer/downloader/123.rar 
  " 
  ,  
  @" 
  C:\123.rar 
  " 
  , progressBar1, label1);
        }
         
  /// 
    
  <summary> 
          
         
  /// 
   c#,.net 下载文件        
         
  /// 
    
  </summary> 
          
         
  /// 
    
  <param name="URL"> 
  下载文件地址 
  </param> 
         
         
  /// 
   
         
  /// 
    
  <param name="Filename"> 
  下载后的存放地址 
  </param> 
          
         
  /// 
    
  <param name="Prog"> 
  用于显示的进度条 
  </param> 
          
         
  /// 
    
  
 
           
  public 
    
  void 
   DownloadFile( 
  string 
   URL,  
  string 
   filename, System.Windows.Forms.ProgressBar prog, System.Windows.Forms.Label label1)
        {
             
  float 
   percent  
  = 
    
  0 
  ;
             
  try 
  
            {
                System.Net.HttpWebRequest Myrq  
  = 
   (System.Net.HttpWebRequest)System.Net.HttpWebRequest.Create(URL);
                System.Net.HttpWebResponse myrp  
  = 
   (System.Net.HttpWebResponse)Myrq.GetResponse();
                 
  long 
   totalBytes  
  = 
   myrp.ContentLength;
                 
  if 
   (prog  
  != 
    
  null 
  )
                {
                    prog.Maximum  
  = 
   ( 
  int 
  )totalBytes;
                }
                System.IO.Stream st  
  = 
   myrp.GetResponseStream();
                System.IO.Stream so  
  = 
    
  new 
   System.IO.FileStream(filename, System.IO.FileMode.Create);
                 
  long 
   totalDownloadedByte  
  = 
    
  0 
  ;
                 
  byte 
  [] by  
  = 
    
  new 
    
  byte 
  [ 
  1024 
  ];
                 
  int 
   osize  
  = 
   st.Read(by,  
  0 
  , ( 
  int 
  )by.Length);
                 
  while 
   (osize  
  > 
    
  0 
  )
                {
                    totalDownloadedByte  
  = 
   osize  
  + 
   totalDownloadedByte;
                    System.Windows.Forms.Application.DoEvents();
                    so.Write(by,  
  0 
  , osize);
                     
  if 
   (prog  
  != 
    
  null 
  )
                    {
                        prog.Value  
  = 
   ( 
  int 
  )totalDownloadedByte;
                    }
                    osize  
  = 
   st.Read(by,  
  0 
  , ( 
  int 
  )by.Length);

                    percent  
  = 
   ( 
  float 
  )totalDownloadedByte  
  / 
   ( 
  float 
  )totalBytes  
  * 
    
  100 
  ;
                    label1.Text  
  = 
    
  " 
  当前补丁下载进度 
  " 
    
  + 
   percent.ToString()  
  + 
    
  " 
  % 
  " 
  ;
                    System.Windows.Forms.Application.DoEvents();  
  // 
  必须加注这句代码，否则label1将因为循环执行太快而来不及显示信息 
  
 
                  }
                so.Close();
                st.Close();
            }
             
  catch 
   (System.Exception)
            {
                 
  throw 
  ;
            }
        }
    }
} 
 

源码下载：http://revit.5d6d.com/thread-997-1-1.html 

From : http://www.cnblogs.com/greatverve/archive/2011/05/17/csharp-down.html