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";
                    }
                    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.aspx

fileNamePath：要上传的本地文件，如：D:\test.rar

saveName：文件上传到服务器后的名称，如：200901011234.rar

progressBar：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。

一切都配置好了，运行效果如下：

为了解决这个问题，我查看了很多文章，记于此，以后遇到同样的问题有个查找的地方。