How to hande errors in multi user application in C#?

sunil meena

Suppose in an application at a time multiple users are online. And because of some reason 4 users got exceptions. As we have global exception handling implemented in our Global.asax file, so we show a custom error page to all the user and log the error using below code:

var currentException = Server.GetLastError();
logger.LogDetails(currentException); // some logging code
Server.ClearError();

User 1 got Divide by zero exception.
User 2 got invalid cast exception.
User 3 got Index out of range exception.
User 4 got some Sqlexception.

What will this Server.GetLastError() return in this case?

Also, I need to log the exceptions. So think of it as, I want to log exception based on user as key and Exception details as description. So for User 1, there will be a log entry something like User=U1, ExceptionDescription="Divide By zero".

I'm worried that GetLastError will return whatever error occured last regardless of user, and if four users get an error there could be crosstalk and they could see each other's errors (or the logging code may log the wrong user name with the wrong error).

I can get current user using HTTPContext but still not able to get exception that is occurred in their session. How can I achieve this?

4 Replies

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sunil meena9y ago

Found the answer of my query. I've also tried it and working as expected.

GetLastError: is thread safe. It retrieves the calling thread's last-error code
value. The last-error code is maintained on a per-thread basis. Multiple threads
do not overwrite each other's last-error code. 

var currentException = Server.GetLastError(); 
var user = HttpContext.Current.User; 
logger.LogDetails(currentException, user); // some logging code 
Server.ClearError();

sunil meena9y ago
Thank you for replying me, but I guess my question is not so clear and I apology for the same. What I want to know that if multiple users are getting different different exceptions at the same time then how can we know that which user got what error. Because if we use Server.GetlastError(), if it is not session specific then it'll over write all the exception and will return last exception always for all the user at the time of logging.
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Nitin Sontakke9y ago
I believe you are better of using components like log4net for logging the exceptions.
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Mangesh G9y ago

One possible way will be to use the Application Object to save the Error.

Make the Dictionary of the Your current session an exception that is occuring

at that time an save these details in application Object an redirect or log the

details afterwards

Dictioary obj = new Dictionary(Current session,Server.lastError)

Application["ExceptionDetails"]=obj

or alternate solution is instead of using the Response.Redirect use Server.Transfer

in the Application_error() an Redirect to the Error Page

On Page Load You can do like this

Exception exception = Server.GetLastError().GetBaseException();

an log the things there

Still My suggestion is to use the exception Loger for each individual method shud

be there instead of the Global error handeling...