Session changes done in application_Error rolled back after redirect

Question

I have an asp.net application and I am trying to handle custom exception using Application_Error. It works nicely but I have new requirement to set the error data in Session obj

Answer 1

The problem might that the AcquireRequestState event might not have fired when the exception was raised in your application, you will be able to set a session value only after this particular event is fired as this is the stage where the application state is set

Answer 2

I've just come across this problem myself and, after a couple of hours of messing around, managed to solve it. The issue is that Application_Error() clears the session after executing as part of some sort of "cleanup" routine which you need to stop.

The solution I found is as follows:

1. Call Server.ClearError(); - this clears the last error from the application and stops the "cleanup" taking place, thus preserving session.

2. The (unwanted imho) side-effect of this is that it no longer performs the automatic redirect to the error page, so you need to explicitly call Response.Redirect("~/error.aspx");

So, something like this:

protected void Application_Error(object sender, EventArgs e)
{
    // Grab the last exception
    Exception ex = Server.GetLastError();

    // put it in session
    Session["Last_Exception"] = ex;

    // clear the last error to stop .net clearing session
    Server.ClearError();

    // The above stops the auto-redirect - so do a redirect!
    Response.Redirect("~/error.aspx");
}

If you don't want to hard-code the URL, you could grab the defaultRedirect URL directly from the customerrors section in the web.config, which would give you something like this:

protected void Application_Error(object sender, EventArgs e)
{
    // Grab the last exception
    Exception ex = Server.GetLastError();

    // put it in session
    Session["Last_Exception"] = ex;

    // clear the last error to stop .net clearing session
    Server.ClearError();

    // The above stops the auto-redirect - so do a redirect using the default redirect from the customErrors section of the web.config!
    var customerrors = (CustomErrorsSection)WebConfigurationManager.OpenWebConfiguration("/").GetSection("system.web/customErrors");
    Response.Redirect(customerrors.DefaultRedirect);
}

Answer 3

You could use the Cache and an appropriate naming strategy for your key, like this:

protected void Application_Error(object sender, EventArgs e)
    {
        HttpContext.Current.Cache["error:" + Session.SessionID] = Server.GetLastError();
        Response.Redirect("Error.aspx");
    }

in the Error.aspx page you ca read it like this:

var error = Cache["error:" + Session.SessionID];

Answer 4

Check this, the problem is with the redirect call.

Don't redirect after setting a Session variable (or do it right)

Answer 5

Add a directive to the Global.asax file, Imports the System.Web Namespace

 <%@ Import Namespace="System.Web" %>


void Application_Error(object sender, EventArgs e) {

   string message = Server.GetLastError().Message;
   Session["error"] = message;
   Server.Transfer("Error.aspx");

}

Write the error message added in the sesion object in the Error.aspx page

 protected void Page_Load(object sender, EventArgs e){
    if (!this.IsPostBack)
        Response.Write(Session["error"].ToString());

}