工作中遇到使用uploadify插件上传文件后，后台代码中的session[XXX]值为null的问题，反复跟踪，发现不是值丢失，而是sessionID发生了变化，而引起SessionID发生变化的原因就是因为使用了uplodify插件
解决方法：
<script type="text/javascript">
var auth = "<% = Request.Cookies[FormsAuthentication.FormsCookieName]==null ?
string.Empty : Request.Cookies[FormsAuthentication.FormsCookieName].Value %>";
var ASPSESSID = "<%= Session.SessionID %>";
$("#uploadifyLogo").uploadify({
...
formData: { ASPSESSID: ASPSESSID, AUTHID: auth }
});
</script>
Global.asax 文件
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);
}
原文地址：
https://www.cnblogs.com/xust/articles/3522367.html
http://stackoverflow.com/questions/1729179/uploadify-session-and-authentication-with-asp-net-mvc
原文地址：https://www.cnblogs.com/spaceMM/p/12343990.html