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这段时间因项目需要，要实现WinForm下的文件上传，个人觉得采用FTP方法太麻烦，还得配置FTP服务器，要通过防火墙也是一个麻烦。本来打算采用WebClient方法，但是采用这个方法实现后，进度条很短时间后就达到最大值，要等待一段时间才能传送完毕，要是文件太大（我这里测试约100M），会出现错误。后来才知道，原来WebClient是在加载完整个文件到内存后才真正开始上传，怪不得会出现前面的问题了。不得已参考了很多文章，老外的一个文章对我启发很大（），是采用HttpWebRequest方法实现的。废话少说，开始进入正题。实现过程如下：

在WinForm里面调用下面的方法来上传文件：

1. // <summary>
2.         /// 将本地文件上传到指定的服务器(HttpWebRequest方法)
3.         /// </summary>
4.         /// <param name="address">文件上传到的服务器</param>
5.         /// <param name="fileNamePath">要上传的本地文件（全路径）</param>
6.         /// <param name="saveName">文件上传后的名称</param>
7.         /// <param name="progressBar">上传进度条</param>
8.         /// <returns>成功返回1，失败返回0</returns>
9.         private int Upload_Request(string address, string fileNamePath, string saveName, ProgressBar progressBar)
10.         {
11.             int returnValue = 0;
13.             // 要上传的文件
14.             FileStream fs = new FileStream(fileNamePath, FileMode.Open, FileAccess.Read);
15.             BinaryReader r = new BinaryReader(fs);
17.             //时间戳
18.             string strBoundary = "----------" + DateTime.Now.Ticks.ToString("x");
19.             byte[] boundaryBytes = Encoding.ASCII.GetBytes("/r/n--" + strBoundary + "/r/n");
21.             //请求头部信息
22.             StringBuilder sb = new StringBuilder();
23.             sb.Append("--");
24.             sb.Append(strBoundary);
25.             sb.Append("/r/n");
26.             sb.Append("Content-Disposition: form-data; name=/"");
27.             sb.Append("file");
28.             sb.Append("/"; filename=/"");
29.             sb.Append(saveName);
30.             sb.Append("/"");
31.             sb.Append("/r/n");
32.             sb.Append("Content-Type: ");
33.             sb.Append("application/octet-stream");
34.             sb.Append("/r/n");
35.             sb.Append("/r/n");
36.             string strPostHeader = sb.ToString();
37.             byte[] postHeaderBytes = Encoding.UTF8.GetBytes(strPostHeader);
39.             // 根据uri创建HttpWebRequest对象
40.             HttpWebRequest httpReq = (HttpWebRequest)WebRequest.Create(new Uri(address));
41.             httpReq.Method = "POST";
43.             //对发送的数据不使用缓存
44.             httpReq.AllowWriteStreamBuffering = false;
46.             //设置获得响应的超时时间（300秒）
47.             httpReq.Timeout = 300000;
48.             httpReq.ContentType = "multipart/form-data; boundary=" + strBoundary;
49.             long length = fs.Length + postHeaderBytes.Length + boundaryBytes.Length;
50.             long fileLength = fs.Length;
51.             httpReq.ContentLength = length;
52.             try
53.             {
54.                 progressBar.Maximum = int.MaxValue;
55.                 progressBar.Minimum = 0;
56.                 progressBar.Value = 0;
58.                 //每次上传4k
59.                 int bufferLength = 4096;
60.                 byte[] buffer = new byte[bufferLength];
62.                 //已上传的字节数
63.                 long offset = 0;
65.                 //开始上传时间
66.                 DateTime startTime = DateTime.Now;
67.                 int size = r.Read(buffer, 0, bufferLength);
68.                 Stream postStream = httpReq.GetRequestStream();
70.                 //发送请求头部消息
71.                 postStream.Write(postHeaderBytes, 0, postHeaderBytes.Length);
72.                 while (size > 0)
73.                 {
74.                     postStream.Write(buffer, 0, size);
75.                     offset += size;
76.                     progressBar.Value = (int)(offset * (int.MaxValue / length));
77.                     TimeSpan span = DateTime.Now - startTime;
78.                     double second = span.TotalSeconds;
79.                     lblTime.Text = "已用时：" + second.ToString("F2") + "秒";
80.                     if (second > 0.001)
81.                     {
82.                         lblSpeed.Text = " 平均速度：" + (offset / 1024 / second).ToString("0.00") + "KB/秒";
83.                     }
84.                     else
85.                     {
86.                         lblSpeed.Text = " 正在连接…";
87.                     }
88.                     lblState.Text = "已上传：" + (offset * 100.0 / length).ToString("F2") + "%";
89.                     lblSize.Text = (offset / 1048576.0).ToString("F2") + "M/" + (fileLength / 1048576.0).ToString("F2") + "M";
90.                     Application.DoEvents();
91.                     size = r.Read(buffer, 0, bufferLength);
92.                 }
93.                 //添加尾部的时间戳
94.                 postStream.Write(boundaryBytes, 0, boundaryBytes.Length);
95.                 postStream.Close();
97.                 //获取服务器端的响应
98.                 WebResponse webRespon = httpReq.GetResponse();
99.                 Stream s = webRespon.GetResponseStream();
100.                 StreamReader sr = new StreamReader(s);
102.                 //读取服务器端返回的消息
103.                 String sReturnString = sr.ReadLine();
104.                 s.Close();
105.                 sr.Close();
106.                 if (sReturnString == "Success")
107.                 {
108.                     returnValue = 1;
109.                 }
110.                 else if (sReturnString == "Error")
111.                 {
112.                     returnValue = 0;
113.                 }
115.             }
116.             catch
117.             {
118.                 returnValue = 0;
119.             }
120.             finally
121.             {
122.                 fs.Close();
123.                 r.Close();
124.             }
126.             return returnValue;
127.         }

参数说明如下：

address：接收文件的URL地址，如：

fileNamePath：要上传的本地文件，如：D:/test.rar

saveName：文件上传到服务器后的名称，如：200901011234.rar

progressBar：显示文件上传进度的进度条。

接收文件的WebForm添加一个Save.aspx页面，Load方法如下：

1. protected void Page_Load(object sender, EventArgs e)
2.         {
3.             if (Request.Files.Count > 0)
4.             {
5.                 try
6.                 {
7.                     HttpPostedFile file = Request.Files[0];
8.                     string filePath = this.MapPath("UploadDocument") + "//" + file.FileName;
9.                     file.SaveAs(filePath);
10.                     Response.Write("Success/r/n");
11.                 }
12.                 catch
13.                 {
14.                     Response.Write("Error/r/n");
15.                 }
16.             }

同时需要配置WebConfig文件的httpRuntime 如下：

<httpRuntime maxRequestLength="102400"  executionTimeout="300"/>

不能的话最大只能上传4M了。要是想上传更大的文件，maxRequestLength，executionTimeout设置大些，同时WinForm下的代码行

//设置获得响应的超时时间（300秒）

            httpReq.Timeout = 300000;

也要修改，另外别忘了看看IIS的连接超时是否设置为足够大。

一切都配置好了，运行效果如下：

为了解决这个问题，我查看了很多文章，记于此，以后遇到同样的问题有个查找的地方。