C# 之 向服务器上传资源 IIS 之 通过 Web.config 修改文件上传大小限制设置方法

　　首先写客服端，winform 应用 或者 WPF 应用 模拟一个post提交：

　　　　　/// <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_Request2(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();  
                //读取服务器端返回的消息  
                StreamReader sr = new StreamReader(s);            
                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;  
        }  

　　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 = "C:\\Documents and Settings\\Administrator\\桌面\\2\\" + file.FileName;//this.MapPath("UploadDocument")  
                string filePath = "D:\\SourceSafe\\testupform\\" + file.FileName;  
                file.SaveAs(filePath);  
                Response.Write("Success");  
            }  
            catch  
            {  
                Response.Write("Error");  
            }  
        }  
        else  
        {  
            Response.Write("Error1");  
        }  
    }  

　　同时需要配置WebConfig文件的httpRuntime 如下：

<httpRuntime maxRequestLength="102400" executionTimeout="300000"/>

　　不修改配置，默认最大只能上传4M了。要是想上传更大的文件，maxRequestLength（KB），executionTimeout（毫秒）设置大些，另外别忘了看看IIS的连接超时是否设置为足够大。

　　注意：IIS7及以后的 Web.config 的配置方式与之前略有不同。见：IIS 之 通过 Web.config 修改文件上传大小限制设置方法 。