ASP.NET :Access Session variable in global.asax

问题:

I have an ASP.NET application and in the Global.asax ' Application Error Event, I am calling a method to trace/log the error.I want to use the session variable content here .I used the below code

void Application_Error(object sender, EventArgs e)
{
     //get reference to the source of the exception chain
     Exception ex = Server.GetLastError().GetBaseException();

     //log the details of the exception and page state to the
     //Windows 2000 Event Log
     GUI.MailClass objMail = new GUI.MailClass();
     string strError = "MESSAGE: " + ex.Message + "<br><br><br>" + "SOURCE: " + ex.Source + "<br>FORM: " + Request.Form.ToString() + "<br>QUERYSTRING: " +    Request.QueryString.ToString() + "<br>TARGETSITE: " + ex.TargetSite + "<br>STACKTRACE: " + ex.StackTrace;
     if (System.Web.HttpContext.Current.Session["trCustomerEmail"] != null)
     {
         strError = "Customer Email : " + Session["trCustomerEmail"].ToString() +"<br />"+ strError;
     }

     //Call a method to send the error details as an Email
     objMail.sendMail("[e-mail]", "[e-mail]", "Error in " + Request.Form.ToString(), strError, 2);   
} 

I am getting an error in the line of code where I am accessing the session variable.Visual Studio is telling that

"Session is not available in this context"

How to get rid of this ? Any thoughts?

Thanks in advance

回答1:

It should work if you do it like this:

strError = System.Web.HttpContext.Current.Session["trCustomerEmail"]

Because that is what I do myself.

What exactly do you mean with: Visual Studio is telling that "Session is not available in this context"? Do you get a compiler error or a run-time exception?

You could try to be more defensive and test if there actually is a current HttpContext and a Session:

if (HttpContext.Current != null &&
    HttpContext.Current.Session != null) {
  strError = HttpContext.Current.Session["trCustomerEmail"]
}

回答2:

I think applicaiton error is specific for the whole application and a session is specific for the user. Maybe you can throw your own Exception where you save the information from the session inside your exception.

回答3:

You may try this:

HttpContext context = ((HttpApplication)sender).Context;

then you must use is like this:

context.Request.QueryString.ToString()
context.Session["key"] = "fasfaasf";

but if the exception was thrown before the Session object is loaded, it will be null