Asp.Net 上传大文件

HttpModule.cs

namespace WebUploadFile
{
    public class HttpUploadModule : IHttpModule
    {      
        /// <summary>
        /// IHttpModule Dispose
        /// </summary>
        public void Dispose(){}

        /// <summary>
        /// init begin request
        /// </summary>
        /// <param name="application"></param>
        public void Init(HttpApplication application)
        {
            application.BeginRequest += new EventHandler(this.Application_BeginRequest);
        }

        /// <summary>
        /// http request file is contains file upload
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void Application_BeginRequest(Object sender, EventArgs e)
        {
            HttpApplication app = sender as HttpApplication;
            HttpWorkerRequest request = GetWorkerRequest(app.Context);
            Encoding encoding = app.Context.Request.ContentEncoding;

            int bytesRead = 0; // 已读数据大小 
            int read;           // 当前读取的块的大小 
            int count = 8192;   // 分块大小 
            byte[] buffer;       // 保存所有上传的数据 

            if (request != null)
            {
                // 返回 HTTP 请求正文已被读取的部分。 
                byte[] tempBuff = request.GetPreloadedEntityBody(); //要上传的文件 

                // 如果是附件上传 
                if (tempBuff != null && IsUploadRequest(app.Request))     //判断是不是附件上传 
                {
                    // 获取上传大小 
                    long length = long.Parse(request.GetKnownRequestHeader(HttpWorkerRequest.HeaderContentLength));

                    buffer = new byte[length];
                    count = tempBuff.Length; // 分块大小 

                    // 将已上传数据复制过去 
                    // 
                    Buffer.BlockCopy(tempBuff, //源数据 
                        0,                       //从0开始读 
                        buffer,                 //目标容器 
                        bytesRead,               //指定存储的开始位置 
                        count);                 //要复制的字节数。 


                    // 开始记录已上传大小 
                    bytesRead = tempBuff.Length;

                    // 循环分块读取，直到所有数据读取结束 
                    while (request.IsClientConnected() && !request.IsEntireEntityBodyIsPreloaded() && bytesRead < length)
                    {
                        // 如果最后一块大小小于分块大小，则重新分块 
                        if (bytesRead + count > length)
                        {
                            count = (int)(length - bytesRead);
                            tempBuff = new byte[count];
                        }

                        // 分块读取 
                        read = request.ReadEntityBody(tempBuff, count);

                        // 复制已读数据块 
                        Buffer.BlockCopy(tempBuff, 0, buffer, bytesRead, read);

                        // 记录已上传大小 
                        bytesRead += read;

                    }
                    if (request.IsClientConnected() && !request.IsEntireEntityBodyIsPreloaded())
                    {
                        // 传入已上传完的数据 
                        InjectTextParts(request, buffer);
                    }
                }
            }
        }


        HttpWorkerRequest GetWorkerRequest(HttpContext context)
        {

            IServiceProvider provider = (IServiceProvider)HttpContext.Current;
            return (HttpWorkerRequest)provider.GetService(typeof(HttpWorkerRequest));
        }

        /// <summary> 
        /// 传入已上传完的数据 
        /// </summary> 
        /// <param name="request"></param> 
        /// <param name="textParts"></param> 
        void InjectTextParts(HttpWorkerRequest request, byte[] textParts)
        {
            BindingFlags bindingFlags = BindingFlags.Instance | BindingFlags.NonPublic;

            Type type = request.GetType();

            while ((type != null) && (type.FullName != "System.Web.Hosting.ISAPIWorkerRequest"))
            {
                type = type.BaseType;
            }

            if (type != null)
            {
                type.GetField("_contentAvailLength", bindingFlags).SetValue(request, textParts.Length);
                type.GetField("_contentTotalLength", bindingFlags).SetValue(request, textParts.Length);
                type.GetField("_preloadedContent", bindingFlags).SetValue(request, textParts);
                type.GetField("_preloadedContentRead", bindingFlags).SetValue(request, true);
            }
        }

        private static bool StringStartsWithAnotherIgnoreCase(string s1, string s2)
        {
            return (string.Compare(s1, 0, s2, 0, s2.Length, true, CultureInfo.InvariantCulture) == 0);
        }

        /// <summary> 
        /// 是否为附件上传 
        /// 判断的根据是ContentType中有无multipart/form-data 
        /// </summary> 
        /// <param name="request"></param> 
        /// <returns></returns> 
        bool IsUploadRequest(HttpRequest request)
        {
            return StringStartsWithAnotherIgnoreCase(request.ContentType, "multipart/form-data");
        }
    }
}

Web.config 配置

<httpModules>
            <add name="ScriptModule" type="System.Web.Handlers.ScriptModule, System.Web.Extensions, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35"/>
            <add name="HttpUploadModule" type="WebUploadFile.HttpUploadModule, WebUploadFile"/>
        </httpModules>
        <httpRuntime maxRequestLength="2000000" executionTimeout="1300"/>

Page 代码

<form id="form1" runat="server">
        <div> 
            <input id="firstFile" type="file" name="firstFile" runat="server" />
            <asp:Button ID="Button1" runat="server" OnClick="Button1_Click" Text="上传" /> 
            <asp:Label ID="Label1" runat="server"></asp:Label>
        </div> 
    </form>

Page.cs 代码

 protected void Button1_Click(object sender, EventArgs e)
        {
            //要保存的位置 
            string strDesPath = "D:\\";
            string strFileName = this.firstFile.PostedFile.FileName;
            strFileName = strDesPath + strFileName.Substring(strFileName.LastIndexOf("\\"));
            // 
            this.firstFile.PostedFile.SaveAs(strFileName);
            this.Label1.Text = "文件保存到了：" + strFileName;
        }