[C#]使用WebClient上传文件并同时Post表单数据字段到服务端

转自：http://www.97world.com/archives/2963

   之前遇到一个问题，就是使用WebClient上传文件的同时，还要Post表单数据字段，一开始以为WebClient可以直接做到，结果发现如果先Post表单字段，就只能获取到字段及其值，如果先上传文件，也只能获取到上传文件的内容。测试了不少时间才发现WebClient不能这么使用。

    Google到相关的解决思路和类，因为发现网上的一些文章不是介绍得太简单就是太复杂，所以这里简单整理一下，既能帮助自己巩固知识，也希望能够帮到大家！如果大家有什么不明白，可以直接留言问我。

    关于WebClient上传文件并同时Post表单数据的实现原理，大家可以参考这篇文章http://www.cnblogs.com/goody9807/archive/2007/06/06/773735.html，介绍得非常详细，但是类和实例有些模糊，所以类和实例可以直接参考本文。

HttpRequestClient类Code：

using System;
using System.Collections;
using System.Collections.Generic;
using System.Linq;
using System.IO;
using System.Text;
using System.Net;

namespace Common.Helper
{
  /// <summary>
  /// description：http post请求客户端
  /// last-modified-date：2012-02-28
  /// </summary>
  public class HttpRequestClient
  {
    #region //字段
    private ArrayList bytesArray;
    private Encoding encoding = Encoding.UTF8;
    private string boundary = String.Empty;
    #endregion

    #region //构造方法
    public HttpRequestClient()
    {
      bytesArray = new ArrayList();
      string flag = DateTime.Now.Ticks.ToString( "x" );
      boundary = "---------------------------" + flag;
    }
    #endregion

    #region //方法
    /// <summary>
    /// 合并请求数据
    /// </summary>
    /// <returns></returns>
    private byte [] MergeContent()
    {
      int length = 0;
      int readLength = 0;
      string endBoundary = "--" + boundary + "--\r\n" ;
      byte [] endBoundaryBytes = encoding.GetBytes(endBoundary);

      bytesArray.Add(endBoundaryBytes);

      foreach ( byte [] b in bytesArray)
      {
        length += b.Length;
      }

      byte [] bytes = new byte [length];

      foreach ( byte [] b in bytesArray)
      {
        b.CopyTo(bytes, readLength);
        readLength += b.Length;
      }

      return bytes;
    }

    /// <summary>
    /// 上传
    /// </summary>
    /// <param name="requestUrl">请求url</param>
    /// <param name="responseText">响应</param>
    /// <returns></returns>
    public bool Upload(String requestUrl, out String responseText)
    {
      WebClient webClient = new WebClient();
      webClient.Headers.Add( "Content-Type" , "multipart/form-data; boundary=" + boundary);

      byte [] responseBytes;
      byte [] bytes = MergeContent();

      try
      {
        responseBytes = webClient.UploadData(requestUrl, bytes);
        responseText = System.Text.Encoding.UTF8.GetString(responseBytes);
        return true ;
      }
      catch (WebException ex)
      {
        Stream responseStream = ex.Response.GetResponseStream();
        responseBytes = new byte [ex.Response.ContentLength];
        responseStream.Read(responseBytes, 0, responseBytes.Length);
      }
      responseText = System.Text.Encoding.UTF8.GetString(responseBytes);
      return false ;
    }

    /// <summary>
    /// 设置表单数据字段
    /// </summary>
    /// <param name="fieldName">字段名</param>
    /// <param name="fieldValue">字段值</param>
    /// <returns></returns>
    public void SetFieldValue(String fieldName, String fieldValue)
    {
      string httpRow = "--" + boundary + "\r\nContent-Disposition: form-data; name=\"{0}\"\r\n\r\n{1}\r\n" ;
      string httpRowData = String.Format(httpRow, fieldName, fieldValue);

      bytesArray.Add(encoding.GetBytes(httpRowData));
    }

    /// <summary>
    /// 设置表单文件数据
    /// </summary>
    /// <param name="fieldName">字段名</param>
    /// <param name="filename">字段值</param>
    /// <param name="contentType">内容内型</param>
    /// <param name="fileBytes">文件字节流</param>
    /// <returns></returns>
    public void SetFieldValue(String fieldName, String filename, String contentType, Byte[] fileBytes)
    {
      string end = "\r\n" ;
      string httpRow = "--" + boundary + "\r\nContent-Disposition: form-data; name=\"{0}\"; filename=\"{1}\"\r\nContent-Type: {2}\r\n\r\n" ;
      string httpRowData = String.Format(httpRow, fieldName, filename, contentType);

      byte [] headerBytes = encoding.GetBytes(httpRowData);
      byte [] endBytes = encoding.GetBytes(end);
      byte [] fileDataBytes = new byte [headerBytes.Length + fileBytes.Length + endBytes.Length];

      headerBytes.CopyTo(fileDataBytes, 0);
      fileBytes.CopyTo(fileDataBytes, headerBytes.Length);
      endBytes.CopyTo(fileDataBytes, headerBytes.Length + fileBytes.Length);

      bytesArray.Add(fileDataBytes);
    }
    #endregion
  }
}

客户端实例代码：

string fileFullName= @"c:\test.txt" ,filedValue= "hello_world" ,responseText = "" ;
FileStream fs = new FileStream(fileFullName, System.IO.FileMode.Open, System.IO.FileAccess.Read);
byte [] fileBytes = new byte [fs.Length];
fs.Read(fileBytes, 0, fileBytes.Length);
fs.Close(); fs.Dispose();

HttpRequestClient httpRequestClient = new HttpRequestClient();
httpRequestClient.SetFieldValue( "key" , filedValue);
httpRequestClient.SetFieldValue( "uploadfile" , Path.GetFileName(fileFullName), "application/octet-stream" , fileBytes);
httpRequestClient.Upload(NormalBotConfig.Instance.GetUploadFileUrl(), out responseText);

服务端实例代码：

if (HttpContext.Current.Request.Files.AllKeys.Length > 0)
{
  string filePath = Path.Combine(HttpContext.Current.Server.MapPath( "~/" ), "UploadFile" , DateTime.Now.Year.ToString(), DateTime.Now.Month.ToString(), DateTime.Now.Day.ToString());
  if (!Directory.Exists(filePath)) Directory.CreateDirectory(filePath);
  //这里我直接用索引来获取第一个文件，如果上传了多个文件，可以通过遍历HttpContext.Current.Request.Files.AllKeys取“key值”，再通过HttpContext.Current.Request.Files[“key值”]获取文件
  HttpContext.Current.Request.Files[0].SaveAs(Path.Combine(filePath, HttpContext.Current.Request.Files[0].FileName));
  string filedValue = HttpContext.Current.Request.Form[ "key" ];
}

使用WebClient或HttpWebRequest模拟上传文件和数据

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;
        }


        属性属性
    }
}


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;
            }

        }
    }
}