在WinForm中通过HTTP协议向服务器端上传文件

Content-Disposition: form-data; name="file"; filename="a.txt"  //文件名

Content-Type: application/octet-stream

//文件的内容

-----------------------8c64f47716481f0

这时候，我们只需自己编码来模拟这么一组数据就行（我们还可以好好借鉴MS的代码呢），以下就是代码（声明一下，我是借用了别人的代码）
public class wwHttp
 {

  /// <summary>
  /// Fires progress events when using GetUrlEvents() to retrieve a URL.
  /// </summary>
  public event OnReceiveDataHandler OnReceiveData;

  /// <summary>
  /// Determines how data is POSTed when cPostBuffer is set.
  /// 1 - UrlEncoded
  /// 2 - Multi-Part form vars
  /// 4 - XML (raw buffer content type: text/xml)
  /// </summary>
  public int PostMode
  {
   get { return this.nPostMode; }
   set { this.nPostMode = value; }
  }

  /// <summary>
  ///  User name used for Authentication.
  ///  To use the currently logged in user when accessing an NTLM resource you can use "AUTOLOGIN".
  /// </summary>
  public string Username
  {
   get { return this.cUsername; }
   set { cUsername = value; }
  }

  /// <summary>
  /// Password for Authentication.
  /// </summary>
  public string Password
  {
   get {return this.cPassword;}
   set {this.cPassword = value;}
  }

  /// <summary>
  /// Address of the Proxy Server to be used.
  /// Use optional DEFAULTPROXY value to specify that you want to IE's Proxy Settings
  /// </summary>
  public string ProxyAddress  
  {
   get {return this.cProxyAddress;}
   set {this.cProxyAddress = value;}
  }

  /// <summary>
  /// Semicolon separated Address list of the servers the proxy is not used for.
  /// </summary>
  public string ProxyBypass
  {
   get {return this.cProxyBypass;}
   set {this.cProxyBypass = value;}
  }

  /// <summary>
  /// Username for a password validating Proxy. Only used if the proxy info is set.
  /// </summary>
  public string ProxyUsername
  {
   get {return this.cProxyUsername;}
   set {this.cProxyUsername = value;}
  }
  /// <summary>
  /// Password for a password validating Proxy. Only used if the proxy info is set.
  /// </summary>
  public string ProxyPassword
  {
   get {return this.cProxyPassword;}
   set {this.cProxyPassword = value;}
  }

  /// <summary>
  /// Timeout for the Web request in seconds. Times out on connection, read and send operations.
  /// Default is 30 seconds.
  /// </summary>
  public int Timeout
  {
   get {return this.nConnectTimeout; }
   set {this.nConnectTimeout = value; }
  }

  /// <summary>
  /// Error Message if the Error Flag is set or an error value is returned from a method.
  /// </summary>
  public string ErrorMsg
  {
   get { return this.cErrorMsg; }
   set { this.cErrorMsg = value; }
  }
  
  /// <summary>
  /// Error flag if an error occurred.
  /// </summary>
  public bool Error
  {
   get { return this.bError; }
   set { this.bError = value; }
  }

  /// <summary>
  /// Determines whether errors cause exceptions to be thrown. By default errors
  /// are handled in the class and the Error property is set for error conditions.
  /// (not implemented at this time).
  /// </summary>
  public bool ThrowExceptions
  {
   get { return bThrowExceptions; }
   set { this.bThrowExceptions = value;}
  }

  /// <summary>
  /// If set to a non-zero value will automatically track cookies. The number assigned is the cookie count.
  /// </summary>
  public bool HandleCookies
  {
   get { return this.bHandleCookies; }
   set { this.bHandleCookies = value; }
  }
  public CookieCollection Cookies {
   get { return this.oCookies; }
   set { this.Cookies = value; }
  }
  public HttpWebResponse WebResponse  {
   get { return this.oWebResponse;}
   set { this.oWebResponse = value; }
  }
  public HttpWebRequest WebRequest  {
   get { return this.oWebRequest; }
   set { this.oWebRequest = value; }
  }

  // *** member properties
  //string cPostBuffer = "";
  MemoryStream oPostStream;
  BinaryWriter oPostData;

  int nPostMode = 1;

  int nConnectTimeout = 30;
  string cUserAgent = "West Wind HTTP .NET";

  string cUsername = "";
  string cPassword = "";

  string cProxyAddress = "";
  string cProxyBypass = "";
  string cProxyUsername = "";
  string cProxyPassword = "";

  bool bThrowExceptions = false;
  bool bHandleCookies = false;
  
  string cErrorMsg = "";
  bool bError = false;
  
  HttpWebResponse oWebResponse;
  HttpWebRequest oWebRequest;
  CookieCollection oCookies;

  string cMultiPartBoundary = "-----------------------------7cf2a327f01ae";

  public void wwHTTP()
  {
   //
   // TODO: Add constructor logic here
   //

  }

  /// <summary>
  /// Adds POST form variables to the request buffer.
  /// HttpPostMode determines how parms are handled.
  /// 1 - UrlEncoded Form Variables. Uses key and value pairs (ie. "Name","Rick") to create URLEncoded content
  /// 2 - Multi-Part Forms - not supported
  /// 4 - XML block - Post a single XML block. Pass in as Key (1st Parm)
  /// other - raw content buffer. Just assign to Key.
  /// </summary>
  /// <param name="Key">Key value or raw buffer depending on post type</param>
  /// <param name="Value">Value to store. Used only in key/value pair modes</param>
  public void AddPostKey(string Key, byte[] Value)
  {
   
   if (this.oPostData == null)
   {
    this.oPostStream = new MemoryStream();
    this.oPostData = new BinaryWriter(this.oPostStream);
   }
   
   if (Key == "RESET")
   {
    this.oPostStream = new MemoryStream();
    this.oPostData = new BinaryWriter(this.oPostStream);
   }

   switch(this.nPostMode)
   {
    case 1:
     this.oPostData.Write(Encoding.GetEncoding(1252).GetBytes(
          Key + "=" + System.Web.HttpUtility.UrlEncode(Value) + "&"));
     break;
    case 2:
     this.oPostData.Write( Encoding.GetEncoding(1252).GetBytes(
      "--" + this.cMultiPartBoundary + "\r\n" +
      "Content-Disposition: form-data; name=\"" +Key+"\"\r\n\r\n") );
     
     this.oPostData.Write( Value );

     this.oPostData.Write( Encoding.GetEncoding(1252).GetBytes("\r\n") );
     break;
    default:
     this.oPostData.Write( Value );
     break;
   }
  }

  public void AddPostKey(string Key, string Value)
  {
   this.AddPostKey(Key,Encoding.GetEncoding(1252).GetBytes(Value));
  }

  /// <summary>
  /// Adds a fully self contained POST buffer to the request.
  /// Works for XML or previously encoded content.
  /// </summary>
  /// <param name="PostBuffer"></param>
  public void AddPostKey(string FullPostBuffer)
  {
   this.oPostData.Write( Encoding.GetEncoding(1252).GetBytes(FullPostBuffer) );
  }

  public bool AddPostFile(string Key,string FileName)
  {
   byte[] lcFile; 

   if (this.nPostMode != 2) {
    this.cErrorMsg = "File upload allowed only with Multi-part forms";
    this.bError = true;
    return false;
   }

   try
   {   
    FileStream loFile = new FileStream(FileName,System.IO.FileMode.Open,System.IO.FileAccess.Read);

    lcFile = new byte[loFile.Length];
    loFile.Read(lcFile,0,(int) loFile.Length);
    loFile.Close();
   }
   catch(Exception e)
   {
    this.cErrorMsg = e.Message;
    this.bError = true;
    return false;
   }

   this.oPostData.Write( Encoding.GetEncoding(1252).GetBytes(
     "--" + this.cMultiPartBoundary + "\r\n"  +
     "Content-Disposition: form-data; name=\"" + Key + "\" filename=\"" +
     new FileInfo(FileName).Name + "\"\r\n\r\n") );

   this.oPostData.Write( lcFile );

   this.oPostData.Write( Encoding.GetEncoding(1252).GetBytes("\r\n")) ;

   return true;
  }

  /// <summary>
  /// Return a the result from an HTTP Url into a StreamReader.
  /// Client code should call Close() on the returned object when done reading.
  /// </summary>
  /// <param name="Url">Url to retrieve.</param>
  /// <param name="WebRequest">An HttpWebRequest object that can be passed in with properties preset.</param>
  /// <returns></returns>
  protected StreamReader GetUrlStream(string Url,HttpWebRequest Request)
  {
   try
   {
    this.bError = false;
    this.cErrorMsg = "";

    if (Request == null)
    {
     Request =  (HttpWebRequest) System.Net.WebRequest.Create(Url);
    }
    
    Request.UserAgent = this.cUserAgent;
    Request.Timeout = this.nConnectTimeout * 1000;

    // *** Save for external access
    this.oWebRequest = Request;

    // *** Handle Security for the request
    if (this.cUsername.Length > 0)
    {
     if (this.cUsername=="AUTOLOGIN")
      Request.Credentials = CredentialCache.DefaultCredentials;
     else
      Request.Credentials = new NetworkCredential(this.cUsername,this.cPassword);
    }

   
    // *** Handle Proxy Server configuration
    if (this.cProxyAddress.Length > 0)
    {
     if (this.cProxyAddress == "DEFAULTPROXY")
     {
      Request.Proxy = new WebProxy();
      Request.Proxy = WebProxy.GetDefaultProxy();
     }
     else
     {
      WebProxy loProxy = new WebProxy(this.cProxyAddress,true);
      if (this.cProxyBypass.Length > 0)
      {
       loProxy.BypassList = this.cProxyBypass.Split(';');
      }

      if (this.cProxyUsername.Length > 0)
       loProxy.Credentials = new NetworkCredential(this.cProxyUsername,this.cProxyPassword);

      Request.Proxy = loProxy;
     }
    }
    
    // *** Handle cookies - automatically re-assign
    if (this.bHandleCookies)
    {
     Request.CookieContainer = new CookieContainer();
     if (this.oCookies != null && this.oCookies.Count > 0)
     {
      Request.CookieContainer.Add(this.oCookies);
     }
    }

    // *** Deal with the POST buffer if any
    if (this.oPostData != null)
    {
     Request.Method = "POST";
     switch (this.nPostMode)
     {
      case 1:
       Request.ContentType = "application/x-www-form-urlencoded";
       // strip off any trailing & which can cause problems with some
       // http servers
//       if (this.cPostBuffer.EndsWith("&"))
//        this.cPostBuffer = this.cPostBuffer.Substring(0,this.cPostBuffer.Length-1);
       break;
      case 2:
       Request.ContentType = "multipart/form-data; boundary=" + this.cMultiPartBoundary;
       this.oPostData.Write( Encoding.GetEncoding(1252).GetBytes( "--" + this.cMultiPartBoundary + "\r\n" ) );
       break;
      case 4:
       Request.ContentType = "text/xml";
       break;
      default:
       goto case 1;
     }
     

     Stream loPostData = Request.GetRequestStream();
     //loPostData.Write(lcPostData,0,lcPostData.Length);
     this.oPostStream.WriteTo(loPostData);   
     
     byte[] buffer = new byte[this.oPostStream.Length];
     buffer = this.oPostStream.ToArray();
     Console.Write(Encoding.GetEncoding(1252).GetString(buffer,0,buffer.Length));

     //*** Close the memory stream
     this.oPostStream.Close();
     this.oPostStream = null;

     
     //*** Close the Binary Writer
     this.oPostData.Close();
     this.oPostData = null;

     //*** Close Request Stream
     loPostData.Close();

     // *** clear the POST buffer
     //this.cPostBuffer = "";
    }
  
  
    // *** Retrieve the response headers
    HttpWebResponse Response = (HttpWebResponse) Request.GetResponse();

    // ** Save cookies the server sends
    if (this.bHandleCookies) 
    {
     if (Response.Cookies.Count > 0) 
     {
      if (this.oCookies == null) 
      {
       this.oCookies = Response.Cookies;
      }
      else
      {
       // ** If we already have cookies update the list
       foreach (Cookie oRespCookie in Response.Cookies) 
       {
        bool bMatch = false;
        foreach(Cookie oReqCookie in this.oCookies) 
        {
         if (oReqCookie.Name == oRespCookie.Name) 
         {
          oReqCookie.Value = oRespCookie.Name;
          bMatch = true;
          break; //
         }
        } // for each ReqCookies
        if (!bMatch)
         this.oCookies.Add(oRespCookie);
       } // for each Response.Cookies
      }  // this.Cookies == null
     } // if Response.Cookie.Count > 0
    }  // if this.bHandleCookies = 0

    
    // *** Save the response object for external access
    this.oWebResponse = Response;

    Encoding enc;
    try
    {
     if (Response.ContentEncoding.Length  > 0)
      enc = Encoding.GetEncoding(Response.ContentEncoding);
     else
      enc = Encoding.GetEncoding(1252);
    }
    catch
    {
     // *** Invalid encoding passed
     enc = Encoding.GetEncoding(1252);
    }
    
    // *** drag to a stream
    StreamReader strResponse =
     new StreamReader(Response.GetResponseStream(),enc);
    return strResponse;
   }
   catch(Exception e)
   {
    if (this.bThrowExceptions)
     throw e;

    this.cErrorMsg = e.Message;
    this.bError = true;
    return null;
   }
  }

  /// <summary>
  /// Return a the result from an HTTP Url into a StreamReader.
  /// Client code should call Close() on the returned object when done reading.
  /// </summary>
  /// <param name="Url">Url to retrieve.</param>
  /// <returns></returns>
  public StreamReader GetUrlStream(string Url)
  {
   HttpWebRequest oHttpWebRequest = null;
   return this.GetUrlStream(Url,oHttpWebRequest);
  }

  /// <summary>
  /// Return a the result from an HTTP Url into a StreamReader.
  /// Client code should call Close() on the returned object when done reading.
  /// </summary>
  /// <param name="Request">A Request object</param>
  /// <returns></returns>
  public StreamReader GetUrlStream(HttpWebRequest Request)
  {
   return this.GetUrlStream(Request.RequestUri.AbsoluteUri,Request);
  }

  /// <summary>
  /// Return a the result from an HTTP Url into a string.
  /// </summary>
  /// <param name="Url">Url to retrieve.</param>
  /// <returns></returns>
  public string GetUrl(string Url)
  {
   StreamReader oHttpResponse = this.GetUrlStream(Url);
   if (oHttpResponse == null)
    return "";

   string lcResult = oHttpResponse.ReadToEnd();
   oHttpResponse.Close();

   return lcResult;
  }

  /// <summary>
  /// Return a the result from an HTTP Url into a string.
  /// </summary>
  /// <param name="Url">Url to retrieve.</param>
  /// <returns></returns>
  public byte[] GetUrlBytes(string Url)
  {
   StreamReader oHttpResponse = this.GetUrlStream(Url);
   
   if (oHttpResponse == null)
   {
    return null;
   }

   string lcResult = oHttpResponse.ReadToEnd();
   oHttpResponse.Close();

   return null;
  }

  /// <summary>
  /// Retrieves URL with events in the OnReceiveData event.
  /// </summary>
  /// <param name="Url"></param>
  /// <param name="BufferSize"></param>
  /// <returns></returns>
  public string GetUrlEvents(string Url,long BufferSize)
  {
  
   StreamReader oHttpResponse = this.GetUrlStream(Url);
   if (oHttpResponse == null)
    return "";

   long lnSize = BufferSize;
   if (this.oWebResponse.ContentLength > 0)
    lnSize = this.oWebResponse.ContentLength;
   else
    lnSize = 0;

   Encoding enc = Encoding.GetEncoding(1252);

   StringBuilder loWriter = new StringBuilder((int) lnSize);
      
   char[] lcTemp = new char[BufferSize];

   OnReceiveDataEventArgs oArgs = new OnReceiveDataEventArgs();
   oArgs.TotalBytes = lnSize;

   lnSize = 1;
   int lnCount = 0;
   long lnTotalBytes = 0;

   while (lnSize > 0)
   {
    lnSize = oHttpResponse.Read(lcTemp,0,(int) BufferSize);
    if (lnSize > 0)
    {
     loWriter.Append( lcTemp,0,(int) lnSize );
     lnCount++;
     lnTotalBytes += lnSize;

     // *** Raise an event if hooked up
     if (this.OnReceiveData != null)
     {
      /// *** Update the event handler
      oArgs.CurrentByteCount = lnTotalBytes;
      oArgs.NumberOfReads = lnCount;
      oArgs.CurrentChunk = lcTemp;
      this.OnReceiveData(this,oArgs);

      // *** Check for cancelled flag
      if (oArgs.Cancel)
       goto CloseDown;
     }
    }
   } // while

  CloseDown:
   oHttpResponse.Close();

   // *** Send Done notification
   if (this.OnReceiveData != null && !oArgs.Cancel)
   {
    // *** Update the event handler
    oArgs.Done = true;
    this.OnReceiveData(this,oArgs);
   }

//   return lcHtml;
   return loWriter.ToString();
  }

  public delegate void OnReceiveDataHandler(object sender, OnReceiveDataEventArgs e);
  public class OnReceiveDataEventArgs
  {
   public long CurrentByteCount=0;
   public long TotalBytes = 0;
   public int NumberOfReads = 0;
   public char[] CurrentChunk;
   public bool Done = false;
   public bool Cancel = false;
  }  
 }

在wwHttp这个类里面，不仅仅可以传送文件AddPostFile方法，还可以传送变量AddPostKey方法。

这样，如果我们要通过代理服务器传送文件，就可以编写如下的代码了：
wwHttp ww = new wwHttp();
   ww.ProxyAddress = "202.132.156.124";   
   ww.PostMode = 2;
   ww.AddPostKey("testKey","test");
   ww.AddPostFile("myfile",@"D:\Temp\Java\JavaStart\JavaStart2.jar");  
   
   string shtml = ww.GetUrlEvents("http://localhost/UploadFileWeb/WebForm1.aspx",409600);
   Console.Write(shtml);

小结：

（1）通过Web Services传文件。

（2）如果不需要使用代理，使用WebClient类

（3）如果需要使用代理，使用扩展得到的类wwHttp