C# 模拟form表单上传文件

 1         public static string UploadFile(string url, string filePath, string fileName)
 2         {
 3             FileStream fs = new FileStream(filePath, FileMode.Open, FileAccess.Read);
 4             var buffer = new byte[fs.Length]; // 二进制文件
 5             fs.Read(buffer, 0, Convert.ToInt32(fs.Length));
 6             fs.Close();
 7 
 8             string boundary = "---------------------------" + DateTime.Now.Ticks.ToString("x");
 9             string PREFIX = "--", LINE_END = "\r\n";
10 
11             StringBuilder sb = new StringBuilder();
12             sb.Append(PREFIX + boundary + LINE_END);
13             sb.Append("Content-Disposition: form-data; name=\"" + fileName + "\"; filename=\"" + fileName + "\"" + LINE_END);
14             sb.Append("Content-Type: " + fileName.Split('.')[1] + LINE_END + LINE_END);
15             WebRequest request = WebRequest.Create(url);
16             request.Method = "POST";
17             request.ContentType = "multipart/form-data;boundary=" + boundary;
18             Stream dataStream = request.GetRequestStream();
19             dataStream.Write(Encoding.UTF8.GetBytes(sb.ToString()), 0, Encoding.UTF8.GetByteCount(sb.ToString()));
20             dataStream.Write(buffer, 0, buffer.Length);
21             dataStream.Write(Encoding.UTF8.GetBytes(LINE_END + PREFIX + boundary + PREFIX + LINE_END), 0, Encoding.UTF8.GetByteCount(LINE_END + PREFIX + boundary + PREFIX + LINE_END));
22             dataStream.Close();
23 
24             WebResponse webResponse = request.GetResponse();
25             Stream newStream = webResponse.GetResponseStream();
26 
27             StreamReader rdr = new StreamReader(newStream);
28             var result = rdr.ReadToEnd();
29             return result;
30         }