今天在使用uploadify时发现session会发生丢失的情况，经过一番研究发现，其丢失并不是真正的丢失，而是在使用Flash上传控件的时候使用的session机制和asp.net中的不相同。为解决这个问题使用两种方案，下面进行介绍

第一种：修改Gobal前台aspx页面：

$("#uploadify").uploadify({

'uploader': '/LZKS/Handler/BigFileUpLoadHandler.ashx',

'swf': '/LZKS/Scripts/uploadify/uploadify.swf',

'cancelImage': '/LZKS/Scripts/uploadify/cancel.png',

'queueID': 'fileQueue',

//'auto': false,

'multi': true,

'buttonText': '文件上传',

'formData': { 'ASPSESSID': ASPSESSID, 'AUTHID': auth },

'onSelect': function (file) {

$('#uploadify').uploadifySettings('formData', { 'ASPSESSID': ASPSESSID, 'AUTHID': auth });

alert(formDate);

},

'onComplete': function (file, data, response) {

},

'onQueueComplete': function () {

alert("上传完成！");

$('#fileQueue').attr('style', 'visibility :hidden');

},

'onSelectError': function (file, errorCode, errorMsg) {

$('#fileQueue').attr('style', 'visibility :hidden');

},

'onUploadStart': function (file) {

$('#fileQueue').attr('style', 'top:200px;left:400px;width:400px;height :400px;visibility :visible');

}

});

});

接着修改Gobal中的代码：

protected void Application_BeginRequest(object sender, EventArgs e)

{

/* we guess at this point session is not already retrieved by application so we recreate cookie with the session id... */

try

{

string session_param_name = "ASPSESSID";

string session_cookie_name = "ASP.NET_SessionId";

if (HttpContext.Current.Request.Form[session_param_name] != null)

{

UpdateCookie(session_cookie_name, HttpContext.Current.Request.Form[session_param_name]);

}

else if (HttpContext.Current.Request.QueryString[session_param_name] != null)

{

UpdateCookie(session_cookie_name, HttpContext.Current.Request.QueryString[session_param_name]);

}

}

catch

{

}

try

{

string auth_param_name = "AUTHID";

string auth_cookie_name = FormsAuthentication.FormsCookieName;

if (HttpContext.Current.Request.Form[auth_param_name] != null)

{

UpdateCookie(auth_cookie_name, HttpContext.Current.Request.Form[auth_param_name]);

}

else if (HttpContext.Current.Request.QueryString[auth_param_name] != null)

{

UpdateCookie(auth_cookie_name, HttpContext.Current.Request.QueryString[auth_param_name]);

}

}

catch

{

}

}

private void UpdateCookie(string cookie_name, string cookie_value)

{

HttpCookie cookie = HttpContext.Current.Request.Cookies.Get(cookie_name);

if (null == cookie)

{

cookie = new HttpCookie(cookie_name);

}

cookie.Value = cookie_value;

HttpContext.Current.Request.Cookies.Set(cookie);

}

在JS加载前面定义下面两个变量

var auth = "";

var ASPSESSID = "";

Handler文件代码如下：

public class BigFileUpLoadHandler : IHttpHandler, IRequiresSessionState

{

DALFile Fdal = new DALFile();

public void ProcessRequest(HttpContext context)

{

context.Response.ContentType = "text/plain";

VideoUpLoad(context, CLSOFT.Web.LZKS.Edu.Globe.filename);

}

public void VideoUpLoad(HttpContext context, string fileFolderName)

{

context.Response.Charset = "utf-8";

string aaaaaaa=context.Request.QueryString["sessionid"];

HttpPostedFile file = context.Request.Files["Filedata"];

string uploadPath = HttpContext.Current.Server.MapPath(UploadFileCommon.CreateDir(fileFolderName));

if (file != null)

{

if (!Directory.Exists(uploadPath))

{

Directory.CreateDirectory(uploadPath);

}

Model.ModelFile model = new Model.ModelFile();

model.File_ID = Guid.NewGuid().ToString();

model.File_Name = file.FileName;

model.File_Path = UploadFileCommon.CreateDir(fileFolderName);

model.File_Size = file.ContentLength;

model.File_Extension = file.FileName.Substring(file.FileName.LastIndexOf('.') + 1);

model.File_Date = DateTime.Now;

model.File_CurrentMan = CLSOFT.Web.LZKS.Edu.Globe.name;

file.SaveAs(uploadPath + model.File_Name);

List list = null;

if (context.Session["File"] == null)

{

list = new List();

}

else

{

list = context.Session["File"] as List;

}

list.Add(model);

context.Session.Add("File", list);

}

else

{

context.Response.Write("0");

}

}

这段代码的功能是将多文件的信息存到context.Session["File"] as List为文件信息类 实现批量上传的信息给Session

第二种方案：直接向后台传递session值

Ext.onReady(function () {

Ext.QuickTips.init();

$("#uploadify").uploadify({

'uploader': '../Uploadify-v2.1.4/uploadify.swf',//上传swf相对路径

'script': '../Service/FileUploadHelper.ashx',//后台上传处理呈现

'cancelImg': '../Uploadify-v2.1.4/cancel.png',//取消上传按钮相对路径

'checkExisting':true,//服务端重复文件检测

'folder': '../UploadFile/',//上传目录

'fileExt':'*.jpg;*.png;*.gif;*.bmp',//允许上传的文件格式

'fileDesc':'jpg、png、gif、bmp',//文件选择时显示的提示

'queueID': 'fileQueue',//上传容器

'auto': false,

'multi': false,//只允许单文件上传

'buttonText':'Choose File',

'scriptData': { 'name': '', 'type': '','length':'' },//在加载时此处是null

//'onInit':function(){alert("1");},//初始化工作，在Extjs的嵌套中最先触发的函数

//选择一个文件后触发

'onSelect': function(event, queueID, fileObj) {

// alert("唯一标识:" + queueID + "\r\n" +

// "文件名：" + fileObj.name + "\r\n" +

// "文件大小：" + fileObj.size + "\r\n" +

// "创建时间：" + fileObj.creationDate + "\r\n" +

// "最后修改时间：" + fileObj.modificationDate + "\r\n" +

// "文件类型：" + fileObj.type);

$("#uploadify").uploadifySettings("scriptData", { "length": fileObj.size}); //动态更新配(执行此处时可获得值)

},

//上传单个文件接收后触发

'onComplete': function (event, queueID, fileObj, response, data) {

var value = response;

if(value==1){

Ext.Msg.alert("提示","上传成功");

}

else if(value==0){

Ext.Msg.alert("提示","请选择上传文件");

}

else if(value==-1){

Ext.Msg.alert("提示","已存在该文件");

}

}

});

动态的传递参数，并判断是否合法

//动态加载

function loadFileType(){

//检测

var medianame=Ext.getCmp("eName").getValue();

if(medianame.trim()==""){

Ext.Msg.alert("提示","媒体名称不能为空");

return;

}

var filetype=Ext.getCmp("eType").getValue();

if(filetype=="" || filetype<0){

Ext.Msg.alert("提示","请选择媒体类型");

return;

}

//动态更新配(执行此处时可获得值)

$("#uploadify").uploadifySettings("scriptData", { "name": medianame,"type":filetype,"sessionuserid": });

//上传开始

$('#uploadify').uploadifyUpload();

}

是取后台的一个变量，该变量在加载页面的时候获得了session值。当然也可以在前台直接获得session值。

后台处理程序：

public class FileUploadHelper : IRequiresSessionState, IHttpHandler

{

int nCurrentUserID = -1;

public void ProcessRequest(HttpContext context)

{

try

{

nCurrentUserID = WebUtil.GetCurrentUserID();//该处的session值得不到

}

catch (Exception)

{

}

context.Response.ContentType = "text/plain";

context.Response.Charset = "utf-8";

string strFilename = string.Empty;

int nFiletype = 0;

float fFilelength = 0;

string strFileExt = string.Empty;

string strFilePath = string.Empty;

if (context.Request["sessionuserid"] != null)

{

nCurrentUserID = Convert.ToInt32(context.Request["sessionuserid"].ToString());

}

if (context.Request["name"] != null)//获得文件名(动态参数)

{

strFilename = context.Request["name"].ToString();

}

if (context.Request["type"] != null)//获得文件类型(动态参数)

{

nFiletype = Convert.ToInt32(context.Request["type"].ToString());

}

if (context.Request["length"] != null)//获得文件长度(动态参数)

{

int nEmptFileLength = Convert.ToInt32(context.Request["length"].ToString());

fFilelength = (float)nEmptFileLength / 1024;

}

if (context.Request["Filename"] != null)//获得文件名(系统自带)

{

string filename = context.Request["Filename"].ToString();

strFileExt = Path.GetExtension(filename).ToLower();//获得后缀名

}

HttpPostedFile file = context.Request.Files["Filedata"];

string uploadPath = HttpContext.Current.Server.MapPath(@context.Request["folder"]);

//根据当前日期创建一个文件夹

string dirName = System.DateTime.Now.ToString("yyyyMMdd");

uploadPath += dirName;

string tmpRootDir = context.Server.MapPath(System.Web.HttpContext.Current.Request.ApplicationPath.ToString());//获取程序根目录

if (file != null)

{

//判断目录是否存在

if (!Directory.Exists(uploadPath))

{

Directory.CreateDirectory(uploadPath);

}

//判断文件是否存在

strFilePath = uploadPath + "\\" + strFilename + strFileExt;

if (!File.Exists(strFilePath))

{

//写数据库成功保存文件

Media model = new Media();

int newMediaID = -1;

model.media_type = nFiletype;

model.media_name = strFilename + strFileExt;

model.file_path = strFilePath.Replace(tmpRootDir, "");//保存相对目录

model.file_length = fFilelength;

newMediaID = MediaBLL.AddMadia(model, nCurrentUserID);

if (newMediaID > -1)//数据库写入成功

{

//保存文件

file.SaveAs(strFilePath);

//下面这句代码缺少的话，上传成功后上传队列的显示不会自动消失

context.Response.Write("1");

}

}

else

{

context.Response.Write("-1");

}

}

else

{

context.Response.Write("0");

}

}

这样就可以解决该问题了。

希望这两种方法都能帮助大家顺利解决session丢失问题，谢谢大家的阅读。