I am getting a " Thread was being aborted " Exception in an ASP.NET page.I am not at all using any Response.Redirect/Server.Transfer method.Can any one help me to solve this ?
This can happen if the web app is being shut down or forcefully restarted while your code executes. I have seen this happen when your web app writes files to the web directory in which it's hosted, causing a recompile of the web app.
The bad solution is using
Response.Redirect(URL, False)
which will cause not to Response.End() current page, however be careful this might lead problems because rest of the page will get executed and might cause login bypass and similar security and performance issues.
Edit : Apparently you are not using Response.Redirect and you can't catch AbortThreadExecution with Try Catch, which means this answer is totally useless now :)
Although to able to get an answer you need to learn how to ask a question. you need to provide information such as :
Exception details
When it, what are the symptoms
What have you tried and didn't work
Have you manage the isolate the problem?
Error:
Thread was being aborted. at System.Threading.Thread.AbortInternal() at System.Threading.Thread.Abort(Object stateInfo) at System.Web.HttpResponse.End()
This error occurs mainly If You Use Response.End, Response.Redirect, or Server.Transfer
Cause:
The Response.End method ends the page execution and shifts the execution to the Application_EndRequest event in the application’s event pipeline. The line of code that follows Response.End is not executed.
This problem occurs in the Response.Redirect and Server.Transfer methods because both methods call Response.End internally.
Resolution/Solution:
You can use a try-catch statement to catch this exception
or
For Response.End, call the HttpContext.Current.ApplicationInstance.CompleteRequest method instead of Response.End to bypass the code execution to the Application_EndRequest event.
For Response.Redirect, use an overload, Response.Redirect(String url, bool endResponse) that passes false for the endResponse parameter to suppress the internal call to Response.End. For example:
ex: Response.Redirect (“nextpage.aspx”, false);
If you use this workaround, the code that follows Response.Redirect is executed.
For Server.Transfer, use the Server.Execute method instead.
Related
I am using .net framework 4.0, plain asp.net and working with webform. Currently I having a base class to handle all parameter passing and redirect. I wonder is it possible to write a base class to handle nullRefeerenceException from all pages in once, lets say redirect end user to somewhere or display particular error message.
Scenario: For example, some pages must come along with parameter, if no parameter captured, I would like to redirect them to somewhere.
You can try to control the ProcessRequest. You need to test it to see if can do the work you ask for, but this is a good point to capture all errors of your page.
public override void ProcessRequest(HttpContext context)
{
try
{
base.ProcessRequest(context);
}
catch (Exception x)
{
// handle here your error from the page...
}
}
Some more notes
I was use this code on one critical page, but I do not use it for all my page. Even tho can capture the errors, some times you can not do nothing else here other than throw again the final error, so end up that is better to log your unknown and unhandled errors from globa.asax Application_Error, and on page make sure that you use try/catch to handle them where they happens.
After some think maybe is not good practice to use it. Good practice is to use try/catch in the place that you may have throws and not a general one like that.
Last
You also get throw error here when the user close the connection before the end of the render, but if you log the errors you get the same on Application_Error - this is not a page error.
Exception of type 'System.Web.HttpUnhandledException' was thrown. --->
System.Web.HttpException: The remote host closed the connection.
The error code is 0x80072746.
In you Global.asax, handle Application_Error.
When a NullReferenceException is handled by the server a 500 response is created. Redirect all of your server 500 messages however you want. This guide will help.
Definitive Guide to Handling 500 Errors in IIS6, IIS7, ASP.NET MVC3 with Custom Page
You can hook up to every uncatched NullReference Exception, depending on what you want to do.
For instance you can use the global.asax, to be specific the Application_Error Event. You can get a reference to the exception, look for the type and perform a redirect there.
Another way to get ahold of exceptions would be to write your custom error provider, but that wouldn't give you the possibility to perform a redirect.
I'm using the common practice of catching errors in global.asax in my ASP.net application. In global.asax, I have a function Application_Error that logs the errors to the database.
This works very well to log errors that occur when the user requests a page.
However, this does nothing to help when an asynchronous method (a method decorated with the [WebMethod] attribute) called from the client-side throws an exception. The exception simply bubbles up and may be returned to the client-side code, but I would like to have the error handling code run on the server automatically similar to how page errors are logged in global.asax.
How do I accomplish this? One way would be to wrap every single asynchronous method with try-catch, but this doesn't seem like a good solution to me.
One option is to create an ASP.NET output filter that intercepts and logs WebMethod exceptions sent by ASP.NET to the client. Here's the basic idea:
Create a subclass of Stream that captures the content of the response.
When the stream is closed, check whether the response has a 500 status code as well as a "jsonerror: true" header. If so, the response contains a WebMethod exception; log the exception.
In Global.Application_PostMapRequestHandler, install an instance of this class as the output filter for JSON requests.
For complete source code, see this StackOverflow answer.
How to create a global exception handler for a Web Service
I had this error Thread was being aborted., this afternoon in my error log.
The code that caused this error is:
Response.Redirect("Login.aspx", true);
If I change the bool value to false, the error log becomes empty and this error stops coming again, but the program stops working.
If I keep it as such, I am getting this error like nuisance.
I want to know the alternative for using Response.Redirect passing true as the value for the endResponse parameter.
I catch this exception and swallow it because ASP.NET is using exceptions for flow control rather than for an exceptional circumstance.
try
{
// Do stuff.
}
catch(ThreadAbortException)
{
// Do nothing. ASP.NET is redirecting.
// Always comment this so other developers know why the exception
// is being swallowed.
}
catch(OtherExceptionTypes ex)
{
// Log other types of exception.
}
As stated in Response.Redirect(url) ThreadAbortException Solution:
The ThreadAbortException is thrown when you make a call to
Response.Redirect(url) because the system aborts processing of the
current web page thread after it sends the redirect to the response
stream. Response.Redirect(url) actually makes a call to Response.End()
internally, and it's Response.End() that calls Thread.Abort() which
bubbles up the stack to end the thread. Under rare circumstances the
call to Response.End() actually doesn't call Thread.Abort(), but
instead calls HttpApplication.CompleteRequest().
Or simply move Response.Redirect("~/Membership/UserRegistration.aspx"); out of the Try/Catch block.
you can change like this
Response.Redirect ("Login.aspx",false)
then it wont abort.
For all caught errors where you want to redirect, create a 'GoTo' destined out of the Try Catch as follows:
Try
'do stuff
Catch ex As Exception
'logging
GoTo MyRedirection
End Try
'Prevent redirection in case of no errors
Exit Sub
MyRedirection:
Response.Redirect("login.aspx", True)
This neither causes thread abortion nor requires multiple catches.
In the Page_Load() section, I check for valid inputs & incase they are invalid, I transfer the request to a custom error page.
While doing so, a ThreadAbortException is thrown which is caught by my catch block but asp.net transfers the request to unknown exception page.
What am I doing wrong? I dont want the ThreadAbortException to come when I transfer to the error page.
eg:
protected void Page_Load(object sender, EventArgs e)
{
try
{
if (String.IsNullOrEmpty(szProductName))
{
//Product name not given. Hence cant process further.
Server.Transfer(Constants.ERROR_WRONG_INPUTS_ASPX);
}
else
{
//Do something.....
}
}
catch(Exception Ex)
{
}
}
As a workaround, I now use:
Response.Redirect(Constants.ERROR_WRONG_INPUTS_ASPX, false);
instead of Server.Transfer i.e. I allow the process to continue in the background which made required I check for validity & then only executed the remaining code.
My problem is similar to : Exception Handling Application Block Exception Handler running in ASP.NET cannot call Response.End() but it seems it was not answered.
Response.Redirect throws the ThreadAbortException to abort the current page and transfer control to the new page. Adding the false parameter "fixed" this problem because it tells Response.Redirect to complete processing on the current page before transfering control.
I believe though you need to look at your application flow. Having a page transfer to an error page because of input errors seems like an overly complicated way to handle input validation to me. I think you are better off with a postback that displays messages, or doing some validation in javascript before the page is posted.
Any time that Response.End() is called, a ThreadAbortException will occur. Server.Transfer calls Response.End() internally because it immediately ends the current processing and hands off the request to the new page, which becomes responsible for returning information to the browser.
Response.Redirect is more graceful, as it finishes processing the current request and returns a 301 Redirect response to the client. Generally this causes the browser to do a second request to the server to request the redirect URL.
You say it's transferring to an unknown error page, but I'm not sure why. Are you doing so in your Application_Error method in Global.asax? If the error is handled you should be able to control where it's heading off to.
I sugest you get rid of that try...catch block. What are you expecting to catch out there? If you really expect some exceptional situation that depends on your implementation, that would happen further down inside your else block. So you should wrap it with try...finally there.
ASP.NET throws the ThreadAbortException when ending your request but it catches it eventually upper in the call stack so you should not catch that yourself. If you're expecting some other possible state corruption just let it propagate up to the global exception handler; it's not your code that throws.
If a product is missing or if the product isn't in your data store then you might want to consider returning a 404 (Page Not Found). This indicates to the browser - (and to google search spiders!) - that there isn't such a page. Are you planning on using SEO friendly URLS such as:
http://MyServer/MySite/Products/FireFox?
What is the preferred method for handling exceptions in ASP.NET Webforms?
You have the Page_Error method that you add (I think) at web.config level, and the entire site gets redirected there when an error occurs.
Does that mean you shouldn't use try-catch anywhere in a webforms application? (Assuming you don't want to hide any errors)
Only catch the errors you can handle. If you can handle them in a manner that allows the page to continue loading then do so. Any other exception that would wreck the page should not be handled in any control or page as you would not be able to do anything anyways. Let it go to the global.asax handler and make sure you log the exception.
In addition to Andrew's suggestion, make sure to update the web.config file to set CustomErrors to "On" and specify a generic error page to redirect these top level errors. Global_asax will still log the error, and then the user can see a friendly page. It will also allow you to configure a few of the standard type errors, such as 404s and 200s, plus much more.
Web Application will normally consists of UI, Business and Data access layer.Each layer must do its part regarding exception handling. Each layer must (for code re usability) check for error condition and wrap exception(after logging it) and maybe propagated to the calling layer. The UI layer should hide exception and display a friendly message. Catching all exception in UI maybe not a good idea. Exceptions if possible should be logged in Database. This will allow ease of maintainence and correction of bugs
Avoid catching exceptions as far as possible. Try and validate all inputs before you use them. Rigorously validation( both client and server side) inputs with help of validation controls, custom controls and regular expression is a must.
string fname = "abc";
//Always check for condition, like file exists etc...
if (System.IO.File.Exists(fname))
{
}
else
{
}
Always make sure clean up code is called. Using statement or try finally.
You can catch all exceptions in Global.asax (asp.net application file)
void Application_Error(object sender, EventArgs e)
{
// Code that runs when an unhandled error occurs
Exception objErr = Server.GetLastError().GetBaseException();
string err = "Error Caught in Application_Error event\n" +
"Error in: " + Request.Url.ToString() +
"\nError Message:" + objErr.Message.ToString()+
"\nStack Trace:" + objErr.StackTrace.ToString();
EventLog.WriteEntry("Sample_WebApp",err,EventLogEntryType.Error);
Server.ClearError();
//additional actions...
}
and add <customerror> section in your web config to redirect user to a separate page
<customErrors defaultRedirect="error.htm" mode="On">
</customErrors>
Useful links
MSDN
MSDN
Exception Logging- Peter Bromberg
You should use try/catch in places where you can do something meaningful with error, like fixing it or taking a different approach.
For all other cases you should use global try/catch using web.config custom errors page or Application_Error event to log the error and possibly to show it to the user.
If you use validation controls or check and validate user input in your code behind that will go a long way to preventing errors. I do recommend having a generic error page that can log the error for you. In cases where you are unsure of what will happen i suggest catching the error and handling it if at all possible and work on finding a way to know that what you are going to run will work before doing it.
Do you have a specific example in mind of where you might expect to encounter an error of this sort. One that I know of is when a session expires and you can no longer process the page. I check for this on every page load before anything else is run and then redirect the user if this has occurred.