The question is, is it possible that requests for the same session are executed from multiple threads? Are methods in ASP.NET reentrant? Especially we are using AJAX which means that asychronous requests are taking place.
Would this mean to place locks around operations on objects placed inside the session?I know that locks are essential when handling static and application wide variables, but the question is is the same true for session objects?
Assuming a static method like below is called from ASP.NET page,can a different thread(b) overwrite the value of s1 after the first line is executed by thread(a)?If so, can assigning parameters to local variables before manipulation solve this?
public static string TestMethod(string s1, string s2, string s3)
{
s1 = s2 + s3;
....
...
return s1;
}
Is there are a simple way to recreate such thread safety related issues?
On the MSDN page for the Membership.ApplicationName property (which applies to an asp.net membership provider), it warns that although one can change Membership.ApplicationName in code, 'The ApplicationName property is not thread safe for multiple writes, and changing the ApplicationName property value can result in unexpected behavior for multiple users of an application.' They therefore recommend avoiding using it for a 'web application'.
This is because the default SqlMembershipProvider is written as a singleton. But here's my question: is it OK if all the threads in my application process are going to set Membership.ApplicationName to the same thing?
I'm thinking of having multiple applications on my IIS box, each with their own separate application pool. I want to point them to the same location, but based on the hostname, set the application provider to different things. Wouldn't this actually be OK? It might not be a thread-safe operation, but doesn't each application pool have its own process and therefore its own instance of SqlMembershipProvider? So, every thread that tried to set Membership.ApplicationName for a given SqlMembershipProvider instance would be trying to set it to the same thing (the provider that is appropriate for that hostname).
I've seen some code that puts a lock around the following code:
if (!CurrentSessionContext.HasBind(sessionFactory))
{
CurrentSessionContext.Bind(sessionFactory.OpenSession());
}
ISession session = sessionFactory.GetCurrentSession();
[code]...
sessionFactory is a DI-injected singleton and the configuration uses a "web" (not "managed_web") context.
Am I correct in assuming that this code does not require synchronised access?
I want to remove checked items from checklistbox (winform control) in class file method which i am calling asynchronously using deletegate. but it showing me this error message:-
Cross-thread operation not valid: Control 'checkedListBox1' accessed from a thread other than the thread it was created on.
i have tried invoke required but again got the same error. Sample code is below:
[code]....
How can we debbug a multi-thread program to see local variables of each thread using visual studio 2008.
View 1 RepliesI'm new to threading and have used it successfully, but limited. I can spawn a thread and have the main thread reference variables in the spawned thread, but I don't know how to allow the spawned thread to reference (and update) variables in the main thread.
Any example threading code I've seen on the web appears to be WAY more complicated than what I do, so I am unable to understand or integrate into my code.
Here is a quick example of how I use threading:
[code].....
I have a hidden input on my form, and my JavaScript code writes there dynamically generated string based on the user behavior on the page.Later, I access to that inpput via server side code.Many users will be using this page at the same time, so what about thread safety ?I mean, could it be possible that userA has an access to that string generated by userB ? Or maybe server will read that string from each user's Web Browser ?
View 2 RepliesI am reading the Asp.net security documentation on msdn.I come across these tow terms and get really confused.
# WindowsIdentity = WindowsIdentity.GetCurrent()
which returns the identity of the security context of the currently executing Win32 thread.
# Thread = Thread.CurrentPrincipal
which returns the principal of the currently executing .NET thread which rides on top of the Win32 thread.
I have a password page and when someone enters an incorrect password I want to simply foil a brute force attack by having
bool isGoodPassword = (password == expected_password);
lock (this)
{
if (!isGoodPassword)
Thread.Sleep(2000);
}
I would expect that this would allow all correct passwords without stalling, but if one user enters a bad password another successful password from a different user would also be blocked. However, the lock doesn't seem to lock across ASP.NET threads.
I want a example of multithreading .i want to use it in a web form not on console.i am using C#.net .and how to use thread.sleep method for a particular thread.
View 5 RepliesMy application is showing lots of thread wait events in the GetScriptReferencesInternal method of ScriptObjectBuilder. I am running a load test with 150 concurrent sessions and in 10 minutes I see 1000 thread block events. Each event stalls the execution of the thread for an average of 6 seconds.
View 2 RepliesI want to update my UI with work-progress within a thread. So i am planing to call webmethod every 2 seconds to get the current progress status. This is my code but I can not complete it.
[Code].....
I have an ASPX page with several update panels. They all have their UpdateMode="Conditional".
Some panels are refreshed when the user clicks a button and other are refreshed regularly, with a timer.
The panel refreshed with a timer launches a database query and many validations on the data. Then display the result in a panel when errors have been found.
That all works fine except when the validation has to delete files on the disk. (.txt, .jpg, etc it depends). In that case, after the validation is made, I am always kicked out of my website because of the error (Thread was being aborted). So I loose all my session variables which means I am not logged off.
Anybody had that kind of problem ? Is it normal that deleting files AND directories on the server make me loose my session? Is there a way to prevent that ?
AjaxControlToolkit.ToolKitScriptManager.OnInit() throws thread abort exception for every aspx page. I have an asp.net 2.0 Ajax application, where I have set the following properties of ToolScriptManager on my pages.
<ajaxToolkit:ToolkitScriptManager ID="ToolkitScriptManager1" runat="server" EnableScriptGlobalization="true"
EnableScriptLocalization="true" CombineScripts="true" EnablePageMethods="true">
<Scripts>
I have this configuration on all the aspx pages in my application. When I checked the .NET CLR exception Performance counter I figured out a large number of exceptions, mainly one exception per page load is occuring. On running windbg I was noticed that
AjaxControlToolkit.ToolKitScriptManager.OnInit() has the following code block which is getting executed. The OutputCombinedScriptFile() returns true. But since I am setting my controls on DesignTime still designmode is set to false for toolkitscriptmanager.
if (!DesignMode && (null != Context) && OutputCombinedScriptFile(Context))
{
// This was a combined script request that was satisfied; end all processing now
Page.Response.End();
}
I am not sure if this is a reported bug or even a bug with ajax, but this is causing havoc in my load test results as I have around 3 hundred thousand HTTP requests to be handled per day out of which 80% are aspx page requests resulting in a large number of threadafbortexceptions, thus affecting the performance.
I need an explanation regarding some advice I got on this site. I'm doing a newsletter sending app, and I have my mail sent in a seperate thread so the process doesn't slow down the whole web site. A couple of people advised me to set the threads IsBackground property to true. I did this, but was also courious about what this does, so I googled a bit.
As it turns out, setting the IsBackground property to true indicates that "it's okay if the process shuts down while this thread is still running.". Or as microsoft puts it "Any remaining background threads are stopped and do not complete." I don't know if I got this the wrong way but, wouldn't it be better to leave the IsBackground property to false, so that the spawned thread can complete its work regarding the main thread?
I want to execute a process, but after the process is done i would like to execute a query so i know this process is done.The process called ffmpeg is quite big so i start it and wait til its done with this coding:
ffmpeg.Start(); // start !
after invoking an async method using ThreadPool.QueueUserWorkItem how do i lookup the assigned thread id?
View 4 RepliesSo basically here I am trying to wait for my server to connect to my website signaling it that its done and so the page needs to be refreshed(cause sql was updated). Thing is when I try to use the response/request in the thread it simply doesn't want to work.
Here the code
Code:
[code]....
Errors I am getting are:
1. If I have the headers clear thing there it gives requires integrated IIS pipes or something like that.
2.If I don't have the clear headers it says the headers were already sent.
Can we consider that two clients accessing the same method of a web service at the same time are two threads (with all problems involved...) ?Is it the same thing for methods in an asp.net web application ?
View 3 Repliessome details of image:
MessageID 14 and 19 are starting thread.
1 0 Yogendra1 Mishra 19 new msg
0 14 Yogendra1 Mishra 17 y
0 14 Yogendra1 Mishra 16 y
1 0 Yogendra1 Mishra 14 y
i want max messageid of each thread.
now my output should be.
19
17
Does a PageAsyncTask fire off its own thread when used in a .aspx page?
View 1 RepliesI am executing time consuming task in a new thread. ParameterizedThreadStart pts = new ParameterizedThreadStart(WorkingFoo); Thread thread = new Thread(pts);
The WorkingFoo executing the task and keeps track of the progress steps (it can return the total number of "steps" and the current step).
I want to display this information in a progress bar (simple div or ajax control, I don't mind).
I don't want, ofcourse, visually refresh the page that will display the progress. Also I want to reduce as much as possible the number of postbacks. So how do I do that? How to show the current progress from new thread on the web page? Also the page that shows the progress can be closed and re-opned and still get the current status.
I have a thread that runs querying a DB and returning some values. If this values satisfyes a condition, I want to raise a message box (javascript alert) for the client side.
In my system, users can post some tasks in DB, and the thread is going to constantly query the database to check if user has things to do. If user has, the system must alert him through a message box.
I've done javascripts invokings with ClientScript.RegisterStartupScript, and Attributes.Add for buttons. But now I want to call the javascript functions (wich will alert the user that he has things to do) from the midle of a sub (that is executed in a thread), without a submit, load or click event. How can I do it?
I'm developing an ASP.NET forms webapplication using C#. I have a method which creates a new Order for a customer. It looks similar to this;
private string CreateOrder(string userName) {
// Fetch current order
Order order = FetchOrder(userName);[code]....
The problem here is, it is possible that 1 customer in two requests (threads) could cause this method to be called twice while another thread is also inside this method. This can cause two orders to be created.
How can I properly lock this method, so it can only be executed by one thread at a time per customer?
I tried;
Mutex mutex = null;
private string CreateOrder(string userName) {
if (mutex == null) { [code]....
This works, but on some occasions it hangs on WaitOne and I don't know why. Is there an error, or should I use another method to lock?