使用WebClient上传文件并同时Post表单数据字段到服务端

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 = ;

      int readLength = ;

      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, , 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, );

      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, , 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 > )

{

  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[].SaveAs(Path.Combine(filePath, HttpContext.Current.Request.Files[].FileName));

  string filedValue = HttpContext.Current.Request.Form["key"];

}

转：http://www.97world.com/archives/2963#

巴特西

使用WebClient上传文件并同时Post表单数据字段到服务端

HttpRequestClient类Code：

客户端实例代码：

服务端实例代码：

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