C# 采用HttpWebRequest 自定义头信息 上传文件

//uploadFile：上传文件名    groupId：GUID
public string FileUpload(string uploadFile, string groupId)
{
//从流中读取字节块并将该数据写入给定缓冲区buffer中
FileStream fileStream = new FileStream(uploadFile, FileMode.Open, FileAccess.Read);
Byte[] buffer = new Byte[fileStream.Length];
fileStream.Read(buffer, 0, Convert.ToInt32(fileStream.Length));

//boundary setting
string boundary = "----------" + DateTime.Now.Ticks.ToString("x");
string fileName = Path.GetFileName(uploadFile);
string nameOnly = fileName.Substring(0, fileName.LastIndexOf("."));

Dictionary<string, string> Params = new Dictionary<string, string>();
Params.Add("name", fileName);
Params.Add("groupId", groupId);
Params.Add("appModule", "portal");
Params.Add("filePath", "");
Params.Add("thumbnail", "true");
Params.Add("storeType", "1");
Params.Add("property1", "");
Params.Add("property2", "");
Params.Add("property3", "");
Params.Add("property4", "");
Params.Add("property5", "");
Params.Add("flag", "false");

StringBuilder sb = new StringBuilder();

//发送必要字段
foreach (KeyValuePair<string, string> param in Params)
{
sb = sb.Append("--");
sb = sb.Append(boundary);
sb = sb.Append("\r\n");
sb = sb.Append("Content-Disposition: form-data; name=\"" + param.Key + "\"\r\n\r\n");
sb = sb.Append(param.Value);
sb = sb.Append("\r\n");
}

//要发送的文件
sb = sb.Append("--");
sb = sb.Append(boundary);
sb = sb.Append("\r\n");
sb = sb.Append("Content-Disposition: form-data; name=\"" + nameOnly + "\"; filename=\"" + fileName + "\"\r\n");
sb = sb.Append("Content-Type: application/octet-stream\r\n\r\n");

byte[] data = Encoding.Default.GetBytes(sb.ToString());

byte[] end_data = Encoding.Default.GetBytes(("\r\n--" + boundary + "--\r\n"));

Uri uri = new Uri("上传文件地址");

HttpWebRequest webRequset = (HttpWebRequest)WebRequest.Create(uri);
webRequset.ContentType = "multipart/form-data; boundary=" + boundary;
webRequset.Method = "POST";

//长度属性：头+文件流+尾的长度
long length = data.Length + buffer.Length + end_data.Length;
webRequset.ContentLength = length;

Stream requestStream = webRequset.GetRequestStream();
//将拼接的数据和文件流写入
requestStream.Write(data, 0, data.Length);
requestStream.Write(buffer, 0, buffer.Length);
requestStream.Write(end_data, 0, end_data.Length);
//获取返回信息
WebResponse responce = webRequset.GetResponse();
Stream responeStream = responce.GetResponseStream();
StreamReader sr = new StreamReader(responeStream);

return sr.ReadToEnd();
}