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(http://blogs.msdn.com/johan/archive/2006/11/15/are-you-getting-outofmemoryexceptions-when-uploading-large-files.aspx),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:
// <summary>
/// 将本地文件上传到指定的服务器(HttpWebRequest方法)
/// </summary>
/// <param name="address">文件上传到的服务器</param>
/// <param name="fileNamePath">要上传的本地文件(全路径)</param>
/// <param name="saveName">文件上传后的名称</param>
/// <param name="progressBar">上传进度条</param>
/// <returns>成功返回1,失败返回0</returns>
private int Upload_Request(string address, string fileNamePath, string saveName, ProgressBar progressBar)
{
int returnValue = 0;
// 要上传的文件
FileStream fs = new FileStream(fileNamePath, FileMode.Open, FileAccess.Read);
BinaryReader r = new BinaryReader(fs);
//时间戳
string strBoundary = "----------" + DateTime.Now.Ticks.ToString("x");
byte[] boundaryBytes = Encoding.ASCII.GetBytes("\r\n--" + strBoundary + "\r\n");
//请求头部信息
StringBuilder sb = new StringBuilder();
sb.Append("--");
sb.Append(strBoundary);
sb.Append("\r\n");
sb.Append("Content-Disposition: form-data; name=\"");
sb.Append("file");
sb.Append("\"; filename=\"");
sb.Append(saveName);
sb.Append("\"");
sb.Append("\r\n");
sb.Append("Content-Type: ");
sb.Append("application/octet-stream");
sb.Append("\r\n");
sb.Append("\r\n");
string strPostHeader = sb.ToString();
byte[] postHeaderBytes = Encoding.UTF8.GetBytes(strPostHeader);
// 根据uri创建HttpWebRequest对象
HttpWebRequest httpReq = (HttpWebRequest)WebRequest.Create(new Uri(address));
httpReq.Method = "POST";
//对发送的数据不使用缓存
httpReq.AllowWriteStreamBuffering = false;
//设置获得响应的超时时间(300秒)
httpReq.Timeout = 300000;
httpReq.ContentType = "multipart/form-data; boundary=" + strBoundary;
long length = fs.Length + postHeaderBytes.Length + boundaryBytes.Length;
long fileLength = fs.Length;
httpReq.ContentLength = length;
try
{
progressBar.Maximum = int.MaxValue;
progressBar.Minimum = 0;
progressBar.Value = 0;
//每次上传4k
int bufferLength = 4096;
byte[] buffer = new byte[bufferLength];
//已上传的字节数
long offset = 0;
//开始上传时间
DateTime startTime = DateTime.Now;
int size = r.Read(buffer, 0, bufferLength);
Stream postStream = httpReq.GetRequestStream();
//发送请求头部消息
postStream.Write(postHeaderBytes, 0, postHeaderBytes.Length);
while (size > 0)
{
postStream.Write(buffer, 0, size);
offset += size;
progressBar.Value = (int)(offset * (int.MaxValue / length));
TimeSpan span = DateTime.Now - startTime;
double second = span.TotalSeconds;
lblTime.Text = "已用时:" + second.ToString("F2") + "秒";
if (second > 0.001)
{
lblSpeed.Text = " 平均速度:" + (offset / 1024 / second).ToString("0.00") + "KB/秒";