[C#]在WinForm下使用HttpWebRequest上传文件并显示进度

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"; } else { lblSpeed.Text = " 正在连接…"; } lblState.Text = "已上传：" + (offset * 100.0 / length).ToString("F2") + "%"; lblSize.Text = (offset / 1048576.0).ToString("F2") + "M/" + (fileLength / 1048576.0).ToString("F2") + "M"; Application.DoEvents(); size = r.Read(buffer, 0, bufferLength); } //添加尾部的时间戳 postStream.Write(boundaryBytes, 0, boundaryBytes.Length); postStream.Close(); //获取服务器端的响应 WebResponse webRespon = httpReq.GetResponse(); Stream s = webRespon.GetResponseStream(); StreamReader sr = new StreamReader(s); //读取服务器端返回的消息 String sReturnString = sr.ReadLine(); s.Close(); sr.Close(); if (sReturnString == "Success") { returnValue = 1; } else if (sReturnString == "Error") { returnValue = 0; } } catch { returnValue = 0; } finally { fs.Close(); r.Close(); } return returnValue; }参数说明如下：address：接收文件的URL地址，如：http://localhost/UploadFile/Save.aspxfileNamePath：要上传的本地文件，如：D:/test.rarsaveName：文件上传到服务器后的名称，如：200901011234.rarprogressBar：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：protected void Page_Load(object sender, EventArgs e) { if (Request.Files.Count > 0) { try { HttpPostedFile file = Request.Files[0]; string filePath = this.MapPath("UploadDocument") + "//" + file.FileName; file.SaveAs(filePath); Response.Write("Success/r/n"); } catch { Response.Write("Error/r/n"); } } 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。