用 WebClient.UploadData 方法 上载文件数据

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  client|web|数据假如某网站有个表单,例如(url: http://localhost/login.aspx):
  帐号
  密码
  
  我们需要在程序中提交数据到这个表单,对于这种表单,我们可以使用 WebClient.UploadData 方法来实现,将所要上传的数据拼成字符即可,程序很简单:
  
  string uriString = "http://localhost/login.aspx";
  // 创建一个新的 WebClient 实例.
  WebClient myWebClient = new WebClient();
  string postData = "Username=admin&Password=admin";
  // 注意这种拼字符串的ContentType
  myWebClient.Headers.Add("Content-Type","application/x-www-form-urlencoded");
  // 转化成二进制数组
  byte[] byteArray = Encoding.ASCII.GetBytes(postData);
  // 上传数据,并获取返回的二进制数据.
  byte[] responseArray = myWebClient.UploadData(uriString,"POST",byteArray);
  
  
  对于文件上传类的表单,例如(url: http://localhost/uploadFile.aspx):
  文件
  
  对于这种表单,我们可以使用
  String uriString = "http://localhost/uploadFile.aspx";
  
  // 创建一个新的 WebClient 实例.
  WebClient myWebClient = new WebClient();
  
  string fileName = "C:\upload.txt";
  
  // 直接上传,并获取返回的二进制数据.
  byte[] responseArray = myWebClient.UploadFile(uriString,"POST",fileName);
  
  
  还有一种表单,不仅有文字,还有文件,例如(url: http://localhost/uploadData.aspx):
  文件名
  文件
  
  对于这种表单,似乎前面的两种方法都不能适用,对于第一种方法,不能直接拼字符串,对于第二种,我们只能传文件,重新回到第一个方法,注意参数:
  public byte[] UploadData(
   string address,
   string method,
   byte[] data
  );
  在第一个例子中,是通过拼字符串来得到byte[] data参数值的,对于这种表单显然不行,反过来想想,对于uploadData.aspx这样的程序来说,直接通过网页提交数据,后台所获取到的流是什么样的呢?(在我以前的一篇blog中,曾分析过这个问题:asp无组件上传进度条解决方案),最终的数据如下:
  
  -----------------------------7d429871607fe
  Content-Disposition: form-data; name="file1"; filename="G:\homepage.txt"
  Content-Type: text/plain
  宝玉:http://www.webuc.net
  -----------------------------7d429871607fe
  Content-Disposition: form-data; name="filename"
  default filename
  -----------------------------7d429871607fe--
  
  
  所以只要拼一个这样的byte[] data数据Post过去,就可以达到同样的效果了。但是一定要注意,对于这种带有文件上传的,其ContentType是不一样的,例如上面的这种,其ContentType为"multipart/form-data; boundary=---------------------------7d429871607fe"。有了ContentType,我们就可以知道boundary(就是上面的"---------------------------7d429871607fe"),知道boundary了我们就可以构造出我们所需要的byte[] data了,最后,不要忘记,把我们构造的ContentType传到WebClient中(例如:webClient.Headers.Add("Content-Type", ContentType);)这样,就可以通过WebClient.UploadData 方法上载文件数据了。
  
  具体代码如下:
  生成二进制数据类的封装
  
  using System;
  using System.Web;
  using System.IO;
  using System.Net;
  using System.Text;
  using System.Collections;
  
  namespace UploadData.Common
  ...{
   /**//// <summary>
   /// 创建WebClient.UploadData方法所需二进制数组
   /// </summary>
   public class CreateBytes
   ...{
   Encoding encoding = Encoding.UTF8;
  
   /**//// <summary>
   /// 拼接所有的二进制数组为一个数组
   /// </summary>
   /// <param name="byteArrays">数组</param>
   /// <returns></returns>
   /// <remarks>加上结束边界</remarks>
   public byte[] JoinBytes(ArrayList byteArrays)
   ...{
   int length = 0;
   int readLength = 0;
  
   // 加上结束边界
   string endBoundary = Boundary + "--\r\n"; //结束边界
   byte[] endBoundaryBytes = encoding.GetBytes(endBoundary);
   byteArrays.Add(endBoundaryBytes);
  
   foreach(byte[] b in byteArrays)
   ...{
   length += b.Length;
   }
   byte[] bytes = new byte[length];
  
   // 遍历复制
   //
   foreach(byte[] b in byteArrays)
   ...{
   b.CopyTo(bytes, readLength);
   readLength += b.Length;
   }
  
   return bytes;
   }
  
   public bool UploadData(string uploadUrl, byte[] bytes, out byte[] responseBytes)
   ...{
   WebClient webClient = new WebClient();
   webClient.Headers.Add("Content-Type", ContentType);
  
   try
   ...{
   responseBytes = webClient.UploadData(uploadUrl, bytes);
   return true;
   }
   catch (WebException ex)
   ...{
   Stream resp = ex.Response.GetResponseStream();
   responseBytes = new byte[ex.Response.ContentLength];
   resp.Read(responseBytes, 0, responseBytes.Length);
   }
   return false;
   }
  
  
  
   /**//// <summary>
   /// 获取普通表单区域二进制数组
   /// </summary>
   /// <param name="fieldName">表单名</param>
   /// <param name="fieldValue">表单值</param>
   /// <returns></returns>
   /// <remarks>
   /// -----------------------------7d52ee27210a3c\r\nContent-Disposition: form-data; name=\"表单名\"\r\n\r\n表单值\r\n
   /// </remarks>
   public byte[] CreateFieldData(string fieldName, string fieldValue)
   ...{
   string textTemplate = Boundary + "\r\nContent-Disposition: form-data; name=\"{0}\"\r\n\r\n{1}\r\n";
   string text = String.Format(textTemplate, fieldName, fieldValue);
   byte[] bytes = encoding.GetBytes(text);
   return bytes;
   }
  
  
   /**//// <summary>
   /// 获取文件上传表单区域二进制数组
   /// </summary>
   /// <param name="fieldName">表单名</param>
   /// <param name="filename">文件名</param>
   /// <param name="contentType">文件类型</param>
   /// <param name="contentLength">文件长度</param>
   /// <param name="stream">文件流</param>
   /// <returns>二进制数组</returns>
   public byte[] CreateFieldData(string fieldName, string filename,string contentType, byte[] fileBytes)
   ...{
   string end = "\r\n";
   string textTemplate = Boundary + "\r\nContent-Disposition: form-data; name=\"{0}\"; filename=\"{1}\"\r\nContent-Type: {2}\r\n\r\n";
  
   // 头数据
   string data = String.Format(textTemplate, fieldName, filename, contentType);
   byte[] bytes = encoding.GetBytes(data);
  
  
  
   // 尾数据
   byte[] endBytes = encoding.GetBytes(end);
  
   // 合成后的数组
   byte[] fieldData = new byte[bytes.Length + fileBytes.Length + endBytes.Length];
  
   bytes.CopyTo(fieldData, 0); // 头数据
   fileBytes.CopyTo(fieldData, bytes.Length); // 文件的二进制数据
   endBytes.CopyTo(fieldData, bytes.Length + fileBytes.Length); // \r\n
  
   return fieldData;
   }
  
  
   属性#region 属性
   public string Boundary
   ...{
   get
   ...{
   string[] bArray, ctArray;
   string contentType = ContentType;
   ctArray = contentType.Split(';');
   if (ctArray[0].Trim().ToLower() == "multipart/form-data")
   ...{
   bArray = ctArray[1].Split('=');
   return "--" + bArray[1];
   }
   return null;
   }
   }
  
   public string ContentType
   ...{
   get ...{
   if (HttpContext.Current == null)
   ...{
   return "multipart/form-data; boundary=---------------------------7d5b915500cee";
   }
   return HttpContext.Current.Request.ContentType;
   }
   }
   #endregion
   }
  }
  
  
  在Winform中调用
  
  
  using System;
  using System.Drawing;
  using System.Collections;
  using System.ComponentModel;
  using System.Windows.Forms;
  using System.Data;
  
  using UploadData.Common;
  using System.IO;
  
  namespace UploadDataWin
  ...{
   /**//// <summary>
   /// frmUpload 的摘要说明。
   /// </summary>
   public class frmUpload : System.Windows.Forms.Form
   ...{
   private System.Windows.Forms.Label lblAmigoToken;
   private System.Windows.Forms.TextBox txtAmigoToken;
   private System.Windows.Forms.Label lblFilename;
   private System.Windows.Forms.TextBox txtFilename;
   private System.Windows.Forms.Button btnBrowse;
   private System.Windows.Forms.TextBox txtFileData;
   private System.Windows.Forms.Label lblFileData;
   private System.Windows.Forms.Button btnUpload;
   private System.Windows.Forms.OpenFileDialog openFileDialog1;
   private System.Windows.Forms.TextBox txtResponse;
   /**//// <summary>
   /// 必需的设计器变量。
   /// </summary>
   private System.ComponentModel.Container components = null;
  
   public frmUpload()
   ...{
   //
   // Windows 窗体设计器支持所必需的
   //
   InitializeComponent();
  
   //
   // TODO: 在 InitializeComponent 调用后添加任何构造函数代码
   //
   }
  
   /**//// <summary>
   /// 清理所有正在使用的资源。
   /// </summary>
   protected override void Dispose( bool disposing )
   ...{
   if( disposing )
   ...{
   if (components != null)
   ...{
   components.Dispose();
   }
   }
   base.Dispose( disposing );
   }
  
   Windows 窗体设计器生成的代码#region Windows 窗体设计器生成的代码
   /**//// <summary>
   /// 设计器支持所需的方法 - 不要使用代码编辑器修改
   /// 此方法的内容。
   /// </summary>
   private void InitializeComponent()
   ...{
   this.lblAmigoToken = new System.Windows.Forms.Label();
   this.txtAmigoToken = new System.Windows.Forms.TextBox();
   this.lblFilename = new System.Windows.Forms.Label();
   this.txtFilename = new System.Windows.Forms.TextBox();
   this.btnBrowse = new System.Windows.Forms.Button();
   this.txtFileData = new System.Windows.Forms.TextBox();
   this.lblFileData = new System.Windows.Forms.Label();
   this.btnUpload = new System.Windows.Forms.Button();
   this.openFileDialog1 = new System.Windows.Forms.OpenFileDialog();
   this.txtResponse = new System.Windows.Forms.TextBox();
   this.SuspendLayout();
   //
   // lblAmigoToken
   //
   this.lblAmigoToken.Location = new System.Drawing.Point(40, 48);
   this.lblAmigoToken.Name = "lblAmigoToken";
   this.lblAmigoToken.Size = new System.Drawing.Size(72, 23);
   this.lblAmigoToken.TabIndex = 0;
   this.lblAmigoToken.Text = "AmigoToken";
   //
   // txtAmigoToken
   //
   this.txtAmigoToken.Location = new System.Drawing.Point(120, 48);
   this.txtAmigoToken.Name = "txtAmigoToken";
   this.txtAmigoToken.Size = new System.Drawing.Size(248, 21);
   this.txtAmigoToken.TabIndex = 1;
   this.txtAmigoToken.Text = "";
   //
   // lblFilename
   //
   this.lblFilename.Location = new System.Drawing.Point(40, 96);
   this.lblFilename.Name = "lblFilename";
   this.lblFilename.Size = new System.Drawing.Size(80, 23);
   this.lblFilename.TabIndex = 2;
   this.lblFilename.Text = "Filename";
   //
   // txtFilename
   //
   this.txtFilename.Location = new System.Drawing.Point(120, 96);
   this.txtFilename.Name = "txtFilename";
   this.txtFilename.Size = new System.Drawing.Size(248, 21);
   this.txtFilename.TabIndex = 3;
   this.txtFilename.Text = "";
   //
   // btnBrowse
   //
   this.btnBrowse.Location = new System.Drawing.Point(296, 144);
   this.btnBrowse.Name = "btnBrowse";
   this.btnBrowse.TabIndex = 4;
   this.btnBrowse.Text = "浏览...";
   this.btnBrowse.Click += new System.EventHandler(this.btnBrowse_Click);
   //
   // txtFileData
   //
   this.txtFileData.Location = new System.Drawing.Point(120, 144);
   this.txtFileData.Name = "txtFileData";
   this.txtFileData.Size = new System.Drawing.Size(168, 21);
   this.txtFileData.TabIndex = 5;
   this.txtFileData.Text = "";
   //
   // lblFileData
   //
   this.lblFileData.Location = new System.Drawing.Point(40, 144);
   this.lblFileData.Name = "lblFileData";
   this.lblFileData.Size = new System.Drawing.Size(72, 23);
   this.lblFileData.TabIndex = 6;
   this.lblFileData.Text = "FileData";
   //
   // btnUpload
   //
   this.btnUpload.Location = new System.Drawing.Point(48, 184);
   this.btnUpload.Name = "btnUpload";
   this.btnUpload.TabIndex = 7;
   this.btnUpload.Text = "Upload";
   this.btnUpload.Click += new System.EventHandler(this.btnUpload_Click);
   //
   // txtResponse
   //
   this.txtResponse.Location = new System.Drawing.Point(136, 184);
   this.txtResponse.Multiline = true;
   this.txtResponse.Name = "txtResponse";
   this.txtResponse.Size = new System.Drawing.Size(248, 72);
   this.txtResponse.TabIndex = 8;
   this.txtResponse.Text = "";
   //
   // frmUpload
   //
   this.AutoScaleBaseSize = new System.Drawing.Size(6, 14);
   this.ClientSize = new System.Drawing.Size(400, 269);
   this.Controls.Add(this.txtResponse);
   this.Controls.Add(this.btnUpload);
   this.Controls.Add(this.lblFileData);
   this.Controls.Add(this.txtFileData);
   this.Controls.Add(this.btnBrowse);
   this.Controls.Add(this.txtFilename);
   this.Controls.Add(this.lblFilename);
   this.Controls.Add(this.txtAmigoToken);
   this.Controls.Add(this.lblAmigoToken);
   this.Name = "frmUpload";
   this.Text = "frmUpload";
   this.ResumeLayout(false);
  
   }
   #endregion
  
   /**//// <summary>
   /// 应用程序的主入口点。
   /// </summary>
   [STAThread]
   static void Main()
   ...{
   Application.Run(new frmUpload());
   }
  
   private void btnUpload_Click(object sender, System.EventArgs e)
   ...{
   // 非空检验
   if (txtAmigoToken.Text.Trim() == "" || txtFilename.Text == "" || txtFileData.Text.Trim() == "")
   ...{
   MessageBox.Show("Please fill data");
   return;
   }
  
   // 所要上传的文件路径
   string path = txtFileData.Text.Trim();
  
   // 检查文件是否存在
   if (!File.Exists(path))
   ...{
   MessageBox.Show("{0} does not exist!", path);
   return;
   }
  
   // 读文件流
   FileStream fs = new FileStream(path, FileMode.Open,
   FileAccess.Read, FileShare.Read);
  
   // 这部分需要完善
   string ContentType = "application/octet-stream";
   byte[] fileBytes = new byte[fs.Length];
   fs.Read(fileBytes, 0, Convert.ToInt32(fs.Length));
  
  
   // 生成需要上传的二进制数组
   CreateBytes cb = new CreateBytes();
   // 所有表单数据
   ArrayList bytesArray = new ArrayList();
   // 普通表单
   bytesArray.Add(cb.CreateFieldData("FileName", txtFilename.Text));
   bytesArray.Add(cb.CreateFieldData("AmigoToken", txtAmigoToken.Text));
   // 文件表单
   bytesArray.Add(cb.CreateFieldData("FileData", path
   , ContentType, fileBytes));
  
   // 合成所有表单并生成二进制数组
   byte[] bytes = cb.JoinBytes(bytesArray);
  
   // 返回的内容
   byte[] responseBytes;
  
   // 上传到指定Url
   bool uploaded = cb.UploadData("http://localhost/UploadData/UploadAvatar.aspx", bytes, out responseBytes);
  
   // 将返回的内容输出到文件
   using (FileStream file = new FileStream("c:\response.text", FileMode.Create, FileAccess.Write, FileShare.Read))
   ...{
   file.Write(responseBytes, 0, responseBytes.Length);
   }
  
   txtResponse.Text = System.Text.Encoding.UTF8.GetString(responseBytes);
  
   }
  
   private void btnBrowse_Click(object sender, System.EventArgs e)
   ...{
   if(openFileDialog1.ShowDialog() == DialogResult.OK)
   ...{
   txtFileData.Text = openFileDialog1.FileName;
   }
  
   }
   }
  }
  
  
  完整的代码见附件: UploadData.rar(38K)(http://bbs.openlab.net.cn/PostAttachment.aspx?PostID=400927),解压后给web目录建个虚拟目录"UploadData",其中UploadAvatar.aspx是实际的上传处理页,如果上传成功,则返回文件名和文件类型等信息。default.aspx是asp.net页面来调用 WebClient.UploadData方法提交数据,UploadDataWin项目则是winform程序调用。

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