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  • Printing to a remote printer through the internet

    - by Lock
    I have a remote network (A) that is connected to a head office (B) through a private network. Network A only has 1 PC that requires the connection, and this is into a terminal server at network B. We want to save money by getting rid of the private network as only 1 PC now access it and it seems silly to pay ~$400 per month for something that is accessed by 1 PC. A VPN tunnel is out of the question as the provider wants to charge $600 a month for a VPN tunnel (more than a private network? I might get them to check these numbers). I was thinking of 2 options: 1) VPN client on the PC. This wouldn't cost a thing as we already have VPN users available. 2) Open up a port on the firewall of network B, forwarding to the terminal server. Now the problem is this: On the terminal server, the program that is accessed is for printing labels to the printer that is at network A. The program is setup to send all print jobs to a printer that is setup locally on the terminal server, which has its port mapped to the IP address of the printer that is at network A. If we got rid of the VPN tunnel and used clients/open up firewall port, the printer would no longer be able to find network A, and hence printing would not work. Any ideas to combat this issue? Can the printers at the remote network be setup as internet printers? I've never had any experience with internet printers. Can you open up ports and map to a public static IP address?

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  • How to implement Session timeout in Web Server Side?

    - by Morgan Cheng
    I beheld a web framework implementing in-memory session in this way. The session object is added to Cache with timeout. When the time is out, the session is removed from Cache automatically. To protect race condition, each request should acquire lock on given session object to proceed. Each request will "touch" the session in Cache to refresh the timeout. Everything looks fine, until this scenario is discovered. Say, one operation takes a long time, longer than timeout. Another request comes and wait on session lock which is currently hold by the long-time request. Finally, the long-time request is over, it releases the lock. But, since it already takes longer time than timeout, the session object is already removed from Cache. This is obvious because the only request holding the lock doesn't have a chance to "touch" the session object in cache. The second request gets the lock but cannot retrieve the expired Session object. Oops... To fix this issue, the second request has to re-create the Session object. But, this is just like digging a buried dead body from tomb and try to bring it back to life. It causes buggy code. I'm wondering what's the best way to implement timeout in session to handle such scenario. I know that current platform must have good session mechanism. I just want to know the under-the-hood how.

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  • Using boost locks for RAII access to a semaphore

    - by dan
    Suppose I write a C++ semaphore class with an interface that models the boost Lockable concept (i.e. lock(); unlock(); try_lock(); etc.). Is it safe/recommended to use boost locks for RAII access to such an object? In other words, do boost locks (and/or other related parts of the boost thread library) assume that the Lockable concept will only be modeled by mutex-like objects which are locked and unlocked from the same thread? My guess is that it should be OK to use a semaphore as a model for Lockable. I've browsed through some of the boost source and it "seems" OK. The locks don't appear to store explicit references to this_thread or anything like that. Moreover, the Lockable concept doesn't have any function like whichThreadOwnsMe(). It also looks like I should even be able to pass a boost::unique_lock<MySemaphore> reference to boost::condition_variable_any::wait. However, the documentation is not explicitly clear about the requirements. To illustrate what I mean, consider a bare-bones binary semaphore class along these lines: class MySemaphore{ bool locked; boost::mutex mx; boost::condition_variable cv; public: void lock(){ boost::unique_lock<boost::mutex> lck(mx); while(locked) cv.wait(lck); locked=true; } void unlock(){ { boost::lock_guard<boost::mutex> lck(mx); if(!locked) error(); locked=false; } cv.notify_one(); } // bool try_lock(); void error(); etc. } Now suppose that somewhere, either on an object or globally, I have MySemaphore sem; I want to lock and unlock it using RAII. Also I want to be able to "pass" ownership of the lock from one thread to another. For example, in one thread I execute void doTask() { boost::unique_lock<MySemaphore> lock(sem); doSomeWorkWithSharedObject(); signalToSecondThread(); waitForSignalAck(); lock.release(); } While another thread is executing something like { waitForSignalFromFirstThread(); ackSignal(); boost::unique_lock<MySemaphore>(sem,boost::adopt_lock_t()); doMoreWorkWithSameSharedObject(); } The reason I am doing this is that I don't want anyone else to be able to get the lock on sem in between the time that the first thread executes doSomeWorkWithSharedObject() and the time the second executes doMoreWorkWithSameSharedObject(). Basically, I'm splitting one task into two parts. And the reason I'm splitting the task up is because (1) I want the first part of the task to get started as soon as possible, (2) I want to guarantee that the first part is complete before doTask() returns, and (3) I want the second, more time-consuming part of the task to be completed by another thread, possibly chosen from a pool of slave threads that are waiting around to finish tasks that have been started by master threads. NOTE: I recently posted this same question (sort of) here http://stackoverflow.com/questions/2754884/unlocking-a-mutex-from-a-different-thread-c but I confused mutexes with semaphores, and so the question about using boost locks didn't really get addressed.

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  • Modelling boost::Lockable with semaphore rather than mutex (previously titled: Unlocking a mutex fr

    - by dan
    I'm using the C++ boost::thread library, which in my case means I'm using pthreads. Officially, a mutex must be unlocked from the same thread which locks it, and I want the effect of being able to lock in one thread and then unlock in another. There are many ways to accomplish this. One possibility would be to write a new mutex class which allows this behavior. For example: class inter_thread_mutex{ bool locked; boost::mutex mx; boost::condition_variable cv; public: void lock(){ boost::unique_lock<boost::mutex> lck(mx); while(locked) cv.wait(lck); locked=true; } void unlock(){ { boost::lock_guard<boost::mutex> lck(mx); if(!locked) error(); locked=false; } cv.notify_one(); } // bool try_lock(); void error(); etc. } I should point out that the above code doesn't guarantee FIFO access, since if one thread calls lock() while another calls unlock(), this first thread may acquire the lock ahead of other threads which are waiting. (Come to think of it, the boost::thread documentation doesn't appear to make any explicit scheduling guarantees for either mutexes or condition variables). But let's just ignore that (and any other bugs) for now. My question is, if I decide to go this route, would I be able to use such a mutex as a model for the boost Lockable concept. For example, would anything go wrong if I use a boost::unique_lock< inter_thread_mutex for RAII-style access, and then pass this lock to boost::condition_variable_any.wait(), etc. On one hand I don't see why not. On the other hand, "I don't see why not" is usually a very bad way of determining whether something will work. The reason I ask is that if it turns out that I have to write wrapper classes for RAII locks and condition variables and whatever else, then I'd rather just find some other way to achieve the same effect. EDIT: The kind of behavior I want is basically as follows. I have an object, and it needs to be locked whenever it is modified. I want to lock the object from one thread, and do some work on it. Then I want to keep the object locked while I tell another worker thread to complete the work. So the first thread can go on and do something else while the worker thread finishes up. When the worker thread gets done, it unlocks the mutex. And I want the transition to be seemless so nobody else can get the mutex lock in between when thread 1 starts the work and thread 2 completes it. Something like inter_thread_mutex seems like it would work, and it would also allow the program to interact with it as if it were an ordinary mutex. So it seems like a clean solution. If there's a better solution, I'd be happy to hear that also. EDIT AGAIN: The reason I need locks to begin with is that there are multiple master threads, and the locks are there to prevent them from accessing shared objects concurrently in invalid ways. So the code already uses loop-level lock-free sequencing of operations at the master thread level. Also, in the original implementation, there were no worker threads, and the mutexes were ordinary kosher mutexes. The inter_thread_thingy came up as an optimization, primarily to improve response time. In many cases, it was sufficient to guarantee that the "first part" of operation A, occurs before the "first part" of operation B. As a dumb example, say I punch object 1 and give it a black eye. Then I tell object 1 to change it's internal structure to reflect all the tissue damage. I don't want to wait around for the tissue damage before I move on to punch object 2. However, I do want the tissue damage to occur as part of the same operation; for example, in the interim, I don't want any other thread to reconfigure the object in such a way that would make tissue damage an invalid operation. (yes, this example is imperfect in many ways, and no I'm not working on a game) So we made the change to a model where ownership of an object can be passed to a worker thread to complete an operation, and it actually works quite nicely; each master thread is able to get a lot more operations done because it doesn't need to wait for them all to complete. And, since the event sequencing at the master thread level is still loop-based, it is easy to write high-level master-thread operations, as they can be based on the assumption that an operation is complete when the corresponding function call returns. Finally, I thought it would be nice to use inter_thread mutex/semaphore thingies using RAII with boost locks to encapsulate the necessary synchronization that is required to make the whole thing work.

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  • jQuery nested sortables jumpy behaviour

    - by sebbie
    I want to allow user to drag and drop UI elements. I've 'container' and 'control', control may be in container, containers may include other containers (this is important requirement). I created simple prototype using jQuery. HTML: <div class="one"> <div class="control">Control 1</div> <div class="control">Control 2</div> <div class="control container"> Container drag area <div class="control">Subcontrol 1</div> <div class="control">Subcontrol 2</div> <div class="control">Subcontrol 3</div> <div class="control">Subcontrol 4</div> <div class="control">Subcontrol 5</div> <div class="control">Subcontrol 6</div> <div class="control">Subcontrol 7</div> <div class="control">Subcontrol 8</div> <div class="control">Subcontrol 9</div> </div> <div class="control">Control 3</div> Then I created sortables using jQueryUI: $('.one').sortable({ items: 'div.control', placeholder: 'placeholder', forcePlaceholderSize: true }); Now when I'm trying to drag "Subcontrol 8" and place it between "Subcontrol 2" and "Subcontrol 3" for example I'm getting jumpy effect, you can observe it here: http://jsbin.com/egipu4/2 Interesting thing is - when I remove ability to drag "container" then it becomes smooth and perfect (you can see this on jsbin example below "jumpy" example, you can't drag using "Container drag area" span). I tried different "nested" plugins and techniques, google'd for a long time and the only one that worked was on this page: (StackOverflow doesn't allow me to post more than one like, google for "Brian Swartzfager's Blog: Nested List Sort Demo" should be first, sorry!) But it does work great only in jQuery1.2 and very old jQueryUI. If I include latest jQuery (1.3/1.4) and UI (1.7/1.8) it gets jumpy as well. What am I doing wrong?

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  • Shrew VPN Client gives default route- changing the policy stops me from accessing VPN network

    - by Lock
    I am using the shrew client to connect to what I believe is a Netscreen VPN. Now, when connected, the client adds the VPN as the default route. I do not want this- there is only 1 network behind the VPN that I need to access. I found that with the shrew client, you can change the "Policy" settings on the connection, and can add your own networks in that should tunnel over the VPN. I do this, and add my network in, but when I connect the VPN, I get nothing. Can't access the network. Any idea why this would be? I can see my network in the routing table, and its correctly pointing to the correct gateway. A traceroute shows all time-outs, so I can't be 100% sure that it is trying to tunnel over the VPN. Any idea how I can troubleshoot this?

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  • ARM cortex: mutex using bit banding

    - by Jeff V
    Given that, on the ARM Cortex M3, I can: atomically read a single bit atomically set a single bit atomically clear a single bit How can I combine these for a mutex style set of operations: try lock take lock release lock It seems that try_lock or take_lock would require two operations that would not be atomic. Do I need more control to accomplish this? Disable global interrupts would do it but it seems there should be a more surgical approach.

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  • deadlock because of foreign key?

    - by George2
    Hello everyone, I am using SQL Server 2008 Enterprise. I met with deadlock in the following store procedure, but because of my fault, I did not record the deadlock graph. But now I can not reproduce deadlock issue. I want to have a postmortem to find the root cause of deadlock to avoid deadlock in the future. The deadlock happens on delete statement. For the delete statement, Param1 is a column of table FooTable, Param1 is a foreign key of another table (refers to another primary key clustered index column of the other table). There is no index on Param1 itself for table FooTable. FooTable has another column which is used as clustered primary key, but not Param1 column. Here is my guess why there is deadlock, and I want to let people review whether my analysis is correct? Since Param1 column has no index, there will be a table scan, and will acquire table level lock, because of foreign key, the delete operation will also need to check master table (e.g. to acquire lock on master table); Some operation on master table acquires master table lock, but want to acquire lock on FooTable; (1) and (2) cause cycle lock which makes deadlock happen. My analysis correct? Any reproduce scenario? create PROCEDURE [dbo].[FooProc] ( @Param1 int ,@Param2 int ,@Param3 int ) AS DELETE FooTable WHERE Param1 = @Param1 INSERT INTO FooTable ( Param1 ,Param2 ,Param3 ) VALUES ( @Param1 ,@Param2 ,@Param3 ) DECLARE @ID bigint SET @ID = ISNULL(@@Identity,-1) IF @ID > 0 BEGIN SELECT IdentityStr FROM FooTable WHERE ID = @ID END thanks in advance, George

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  • IIS- defining a website as a dev site

    - by Lock
    I am new to IIS. Is there a way during the setup of IIS to have a variable of some sort set that I can use to tell my site that this is the development copy? I am using PHP via IIS 7.5 and would like to have a file with a few lines that define which databases etc is used by my application. Is this the purpose of web.config? I would love there to be a place in the setup of the website where I can set a few variables that are accessibly by my application. That way, when I migrate files to live, I don't need to worry about access details to databases etc.

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  • postfix and iRedMail- Relaying Denied

    - by Lock
    I am trying to setup iRedMail and am way over my head here. I have installed it, and can send emails internally, but not externally. When I send an email from outside, I get the following return email: The error that the other server returned was: 550 550 5.7.1 <[email protected]>... Relaying denied (state 13). Now I have no idea where to start looking! Any ideas? I have really only just installed iRedMail so I am unsure what else I need to do to get it working. I've pointed my MX records to that server, so that shouldnt be the problem. Also- if i stop postfix (so nothing is listening on port 25) and send a test email, I get the same reply back. Why would I get the same reply back even if postfix is stopped? I have run tcpdump over 25 and can see the packets coming in/out, so its definitely a configuration issue! I suppose my question is not really "what is my problem", but more "What configuration needs to be completed on postfix and iRedMail?"

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  • UIButtons creating a native-like keyboard behavior.

    - by camilo
    Greets. A somehow detailed explanation on my problem, and what I have already done, and what I cannot do. I want to create a behavior resembling the one in the iPhone's keyboard. Basically, I want a view to appear when the user taps a button and WHILE the user taps that button. This, I accomplished. When the user lets go of the button WHILE his finger is on that button's area, I want to trigger an action "doing stuff". This, I was also able to do. Since all the buttons are near (like in the keyboard) and I don't want the user to select other button than the one he pressed, I reduced the hit area for the button using the -(BOOL)pointInside:(CGPoint)point withEvent:(UIEvent )event function. When the user presses the button, not lifting its finger, and dragging outside the button area, I want another action to trigger. This is the first problem... This function only triggers when the user's finger is far from the buttons' area, and this time the pointInside function is not being my friend. How can I detect the user finger "left" the button area the moment it exits its bounds? This, in case you didn't realize... was problem 1. The second problem is related with the drag enter. Again, I need to limit the area like in the drag exit. But I suppose that when I solve one of these, the other is the same. The problem is that in order to have a behavior like in the keyboard, I may need to detect the user started the touch in another button, never lifted his finger, and changed to another button. I can detect drag enter and drag exit IN THIS ORDER while on the same button. I cannot detect drag enter when the user first touched anywhere else other than the button where I want to detect the drag enter event. Basically what I need is to detect touch on any button (and not anywhere else in the view), and while the user is changing buttons without lifting the finger, I want to detect the new button being touched. This gigantic paragraph was problem #2. Any help, as you might guess, is highly appreciated. Best Regards. Thanks a lot!

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  • When should I use temporary variables?

    - by Kyle
    Specifically, I'm wondering which of these I should write: shared_ptr<GuiContextMenu> subMenu = items[j].subMenu.lock(); if (subMenu) subMenu->setVisible(false); or: if (items[j].subMenu.lock() items[j].subMenu.lock()->setVisible(false); I am not required to follow any style guidelines. After optimization, I don't think either choice makes a difference in performance. What is generally the preferred style and why?

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  • Testing UDP port connectivity

    - by Lock
    I am trying to test whether I can get to a particular port on a remote server (both of which I have access to) through UDP. Both servers are internet facing. I am using netcat to have a certain port listening. I then use nmap to check for that port to see if it is open, but it doesn't appear to be. Iptables is turned off. Any suggestions why this could be? I am eventually going to setup a VPN tunnel, but because I'm very new to tunnels, I want to make sure I have connectivity on port UDP 1194 before advancing.

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  • Solving a SQL Server Deadlock situation

    - by mjh41
    I am trying to find a solution that will resolve a recurring deadlock situation in SQL server. I have done some analysis on the deadlock graph generated by the profiler trace and have come up with this information: The first process (spid 58) is running this query: UPDATE cds.dbo.task_core SET nstate = 1 WHERE nmboxid = 89 AND ndrawerid = 1 AND nobjectid IN (SELECT nobjectid FROM ( SELECT nobjectid, count(nobjectid) AS counting FROM cds.dbo.task_core GROUP BY nobjectid) task_groups WHERE task_groups.counting > 1) The second process (spid 86) is running this query: INSERT INTO task_core (…) VALUES (…) spid 58 is waiting for a Shared Page lock on CDS.dbo.task_core (spid 86 holds a conflicting intent exclusive (IX) lock) spid 86 is waiting for an Intent Exclusive (IX) page lock on CDS.dbo.task_core (spid 58 holds a conflicting Update lock)

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  • Highlighting correctly in an emacs major mode

    - by Paul Nathan
    Hi, I am developing an emacs major mode for a language (aka mydsl). However, using the techniques on xahlee's site doesn't seem to be working for some reason (possibly older emacs dialect..) The key issues I am fighting with are (1) highlighting comments is not working and (2), the use of regexp-opt lines is not working. I've reviewed the GNU manual and looked over cc-mode and elisp mode... those are significantly more complicated than I need. ;;;Standard # to newline comment ;;;Eventually should also have %% to %% multiline block comments (defun mydsl-comment-dwim (arg) "comment or uncomment" (interactive "*P") (require 'newcomment) (let ((deactivate-mark nil) (comment-start "#") (comment-end "") comment-dwim arg))) (defvar mydsl-events '("reservedword1" "reservedword2")) (defvar mydsl-keywords '("other-keyword" "another-keyword")) ;;Highlight various elements (setq mydsl-hilite '( ; stuff between " ("\"\\.\\*\\?" . font-lock-string-face) ; : , ; { } => @ $ = are all special elements (":\\|,\\|;\\|{\\|}\\|=>\\|@\\|$\\|=" . font-lock-keyword-face) ( ,(regexp-opt mydsl-keywords 'words) . font-lock-builtin-face) ( ,(regexp-opt mydsl-events 'words) . font-lock-constant-face) )) (defvar mydsl-tab-width nil "Width of a tab for MYDSL mode") (define-derived-mode mydsl-mode fundamental-mode "MYDSL mode is a major mode for editing MYDSL files" ;Recommended by manual (kill-all-local-variables) (setq mode-name "MYDSL script") (setq font-lock-defaults '((mydsl-hilite))) (if (null mydsl-tab-width) (setq tab-width mydsl-tab-width) (setq tab-width default-tab-width) ) ;Comment definitions (define-key mydsl-mode-map [remap comment-dwim] 'mydsl-comment-dwim) (modify-syntax-entry ?# "< b" mydsl-mode-syntax-table) (modify-syntax-entry ?\n "> b" mydsl-mode-syntax-table) ;;A gnu-correct program will have some sort of hook call here. ) (provide 'mydsl-mode)

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  • RAD Visual Web Application Creator/ Builder/ Designer for PHP

    - by inhoue
    Hi all, I want to see if any of you know a (free and open source will be ideal) tool/ app that can help build a php web application very quickly without investing too much time on writing codes, preferring drag and drop/ point and click work-flow designer for logic design (see Agile from Outsystems below). Plus, visual designer for the business logic is great since it can help a developer visualize the logic better. There are a lot of GUI builders, form builders out there, but I am looking for one app for the entire web application development process. My goal is to find an application that a team of developers can use together and use the build-in code of the app as much as possible. E.g. the app will provide a modular just for handle user login or a shopping cart; a developer just need to drag and drop the modular to the logic designer and the code will be generated. This way the functionality will be in a module and code will always be standard across developers. So if a new developer get on-board, he will just need to use the system and get up and running quickly. To explain this better: there is a lot php frameworks, e.g. cakephp, CodeIgniter, etc which I can use to help coding, but still I need to create (code) the GUI, writing quite a bit of codes. I am looking for a tool/ app that is a little more high level than those frameworks. Here is 2 examples apps I found during my google search which they have visual logic designer and gui builder in one single app. Also a single click deployment (but I need it to be php apps or at least I can deploy the (php) code to a LAMP/ WAMP server): Wavemaker: for JAVA Agile from Outsystems: for JAVA or .net (This one is really good, with work-flow drag and drop logic designer!) Talend: it is just an ETL tool, but the concept is what I want to bring up. Drag and drop, point and click logic design. Custom code can be added if it is needed, but the drag and drop process already finished the structure and most of the coding of the web app one needs to build. I want to list Adobe Flex, but it is more like a GUI designer + IDE, not exactly what I want to describe here. The drag and drop/ work-flow logic designer is a key for the app. I could go for the CMS route by learning how to extend them, but it is not that flexible for me and is a long learning curve. Anybody came across this type of app before? Or any idea of how can I find those apps? I googled them for long time, I don't see any of them for php and just few (just 2) for Java. Thanks in advance!

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  • Grid sorting with persistent master sort

    - by MikeWyatt
    I have a UI with a grid. Each record in the grid is sorted by a "master" sort column, let's call it a page number. Each record is a story in a magazine. I want the user to be able to drag and drop a record to a new position in the grid and automatically update the page number field to reflect the updated position. Easy enough, right? Now imagine that I also want to have the grid sortable by any other column (story title, section, author name, etc.). How does the drag and drop operation work now? Revert to page number sort during or after the drag and drop operation? This could confuse the user (why did my sort just change?). It would also result in arbitrary row positioning. Would the story now be before the row that was after it when the user dropped it? Or, would it be after the row that was before it? Those rows may now be widely separated after the master order sort. Disable the drag and drop feature if the grid isn't currently sorted by the page number? This would be easy, but the user might wonder why he can't drag and drop at certain times. Knowing to first sort by page number may not be very intuitive. Let the user rearrange his rows, but not make any changes to the page number? Require the user to enter a "Arrange Stories" mode, in which the grid sort is temporarily switched to page number and drag and drop is enabled? They would then exit the mode, and the previous sort would be reapplied. The big difference between this and the second option is that it would be more explicit than simply clicking on a column header. Any other ideas, or reasons why one of the above is the way to go? EDIT I'd like to point out that any of the above is technically possible, and easy to implement. My question is design-related. What is the most intuitive way to solve this problem, from the user's perspective?

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  • How to know user is dragging something when the cursor is not in my window?

    - by Edwin
    Hi folks, We all know you can implement drag-and-drop feature for your Window so that it accepts drag and drop operation, but my question is, how to detect a drag-and-drop operation that's is in progress in other windows, for example, dragging a file in the Windows Explorer? What I want to do is that when a user is dragging a file then my hidden window shows up. Thank you!

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  • Silverlight avoid lose focus on datagrid

    - by lidermin
    Hi, I have a question: How could I keep the focus on a combobox of a cell inside a datagrid in edit mode; even when I drag a textbox inside a scroll viewer to drag & drop. This is the behaviour I need: The user start to edit a cell by double clicking, and a combobox is showed, then the user could drag and drop some text (one of the texboxes inside the scroll viewer) to the combobox I mentioned. The issue is: when I click on one those textboxes to drag & drop, I lose the focus of the datagrid, and I can't drop it to the cell (the combobox), because I lose the edit mode (it's not a combobox anymore, the datagrid is on query mode). How can I achieve the behaviour I need? Please help. Thanks.

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  • .NET 3.5 C# does not offer what I need for locking: Count async saves until 0 again.

    - by Frank Michael Kraft
    I have some records, that I want to save to database asynchronously. I organize them into batches, then send them. As time passes, the batches are processed. In the meanwhile the user can work on. There are some critical operations, that I want to lock him out from, while any save batch is still running asynchronously. The save is done using a TableServiceContext and method .BeginSave() - but I think this should be irrelevant. What I want to do is whenever an async save is started, increase a lock count, and when it completes, decrease the lock count so that it will be zero as soon as all have finished. I want to lock out the critical operation as long as the count is not zero. Furthermore I want to qualify the lock - by business object - for example. I did not find a .NET 3.5 c# locking method, that does fulfil this requirement. A semaphore does not contain a method to check, if the count is 0. Otherwise a semaphore with unlimited max count would do.

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  • Can an asynchronously fired event run synchronously on a form?

    - by cyclotis04
    [VS 2010 Beta with .Net Framework 3.5] I've written a C# component to asynchronously monitor a socket and raise events when data is received. I set the VB form to show message boxes when the event is raised. What I've noticed is that when the component raises the event synchronously, the message box blocks the component code and locks the form until the user closes the message. When it's raised asynchronously, it neither blocks the code, nor locks the form. What I want is a way to raise an event in such a way that it does not block the code, but is called on the same thread as the form (so that it locks the form until the user selects an option.) Can you help me out? Thanks. [Component] using System; using System.Threading; using System.ComponentModel; namespace mySpace { public delegate void SyncEventHandler(object sender, SyncEventArgs e); public delegate void AsyncEventHandler(object sender, AsyncEventArgs e); public class myClass { readonly object syncEventLock = new object(); readonly object asyncEventLock = new object(); SyncEventHandler syncEvent; AsyncEventHandler asyncEvent; private delegate void WorkerDelegate(string strParam, int intParam); public void DoWork(string strParam, int intParam) { OnSyncEvent(new SyncEventArgs()); AsyncOperation asyncOp = AsyncOperationManager.CreateOperation(null); WorkerDelegate delWorker = new WorkerDelegate(ClientWorker); IAsyncResult result = delWorker.BeginInvoke(strParam, intParam, null, null); } private void ClientWorker(string strParam, int intParam) { Thread.Sleep(2000); OnAsyncEvent(new AsyncEventArgs()); OnAsyncEvent(new AsyncEventArgs()); } public event SyncEventHandler SyncEvent { add { lock (syncEventLock) syncEvent += value; } remove { lock (syncEventLock) syncEvent -= value; } } public event AsyncEventHandler AsyncEvent { add { lock (asyncEventLock) asyncEvent += value; } remove { lock (asyncEventLock) asyncEvent -= value; } } protected void OnSyncEvent(SyncEventArgs e) { SyncEventHandler handler; lock (syncEventLock) handler = syncEvent; if (handler != null) handler(this, e, null, null); // Blocks and locks //if (handler != null) handler.BeginInvoke(this, e, null, null); // Neither blocks nor locks } protected void OnAsyncEvent(AsyncEventArgs e) { AsyncEventHandler handler; lock (asyncEventLock) handler = asyncEvent; //if (handler != null) handler(this, e, null, null); // Blocks and locks if (handler != null) handler.BeginInvoke(this, e, null, null); // Neither blocks nor locks } } } [Form] Imports mySpace Public Class Form1 Public WithEvents component As New mySpace.myClass() Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click component.DoWork("String", 1) End Sub Private Sub component_SyncEvent(ByVal sender As Object, ByVal e As pbxapi.SyncEventArgs) Handles component.SyncEvent MessageBox.Show("Synchronous event", "Raised:", MessageBoxButtons.OK) End Sub Private Sub component_AsyncEvent(ByVal sender As Object, ByVal e As pbxapi.AsyncEventArgs) Handles component.AsyncEvent MessageBox.Show("Asynchronous event", "Raised:", MessageBoxButtons.OK) End Sub End Class

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