c#post大文件时（大于500M），会报OutOfMemoryException的错误，后来设置request.ContentLength后，文件上传上去了，但是在关闭流的时候，报错“请求被中止: 请求已被取消”，原因应该是写入的大小跟设置的大小不一样，解决的方法是写入与请求的大小相同的字节数
完整的代码如下：
//post上传文件
public static byte[] PostFile(string url, IEnumerable<UploadFile> files, NameValueCollection values)
{
string boundary = "----------------------------" + DateTime.Now.Ticks.ToString("x");
try
{
HttpWebRequest request = (HttpWebRequest)WebRequest.Create(url);
request.ContentType = "multipart/form-data; boundary=" + boundary;
request.Method = "POST";
request.KeepAlive = true;
request.Credentials = CredentialCache.DefaultCredentials;
long totallength = 0;
//获取文件大小
if (files != null)
{
foreach (UploadFile file in files)
{
FileInfo fi = new FileInfo(file.Filename);
totallength += fi.Length;
}
}
byte[] line = Encoding.ASCII.GetBytes("\r\n--" + boundary + "\r\n");
request.ContentLength = totallength + 80960;
request.Timeout = 1000 * 100;
Stream stream = request.GetRequestStream();
long postlength = 0;
stream.WriteTimeout = 1000 * 100;
//提交文本字段
if (values != null)
{
string format = "\r\n--" + boundary + "\r\nContent-Disposition: form-data; name=\"{0}\";\r\n\r\n{1}";
foreach (string key in values.Keys)
{
string s = string.Format(format, key, values[key]);
byte[] data = Encoding.UTF8.GetBytes(s);
stream.Write(data, 0, data.Length);
totallength += data.Length;
}
stream.Write(line, 0, line.Length);
postlength += line.Length;
}
//提交文件
if (files != null)
{
string fformat = "Content-Disposition: form-data; name=\"{0}\"; filename=\"{1}\"\r\n Content-Type: application/octet-stream\r\n\r\n";
foreach (UploadFile file in files)
{
string s = string.Format(fformat, file.Name, file.Name);
byte[] data = Encoding.UTF8.GetBytes(s);
stream.Write(data, 0, data.Length);
postlength += data.Length;
int bufferSize = 4096; //每次读取的字节数
byte[] buffer = new byte[bufferSize];
System.IO.FileStream inputstream = null;
int ss = 0;
try
{
inputstream = new System.IO.FileStream(file.Filename, System.IO.FileMode.Open);
long fileLength = inputstream.Length;//文件流的长度
int readCount = (int)Math.Ceiling((double)fileLength / bufferSize); //需要对文件读取的次数
int tempCount = 0;//当前已经读取的次数
do
{
inputstream.Read(buffer, 0, bufferSize); //分readCount次读取这个文件流，每次从上次读取的结束位置开始读取bufferSize个字节
//这里加入接收和处理数据的逻辑
stream.Write(buffer, 0, buffer.Length);
postlength += buffer.Length;
tempCount++;
}
while (tempCount < readCount);
}
catch (Exception ex)
{
}
finally
{
if (inputstream != null)
{
inputstream.Close();
inputstream.Dispose();
}
}
stream.Write(line, 0, line.Length);
postlength += line.Length;
}
}
while (postlength < request.ContentLength)
{
stream.WriteByte(0);
postlength++;
}
using (var response = request.GetResponse())
using (var responseStream = response.GetResponseStream())
using (var mstream = new MemoryStream())
{
responseStream.CopyTo(mstream);
stream.Close();
return mstream.ToArray();
}
}
catch (Exception ex)
{
}
return null;
}
//UploadFile类
public class UploadFile
{
public UploadFile()
{
ContentType = "application/octet-stream";
}
public string Name { get; set; }
public string Filename { get; set; }
public string ContentType { get; set; }
}