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  • Reset the controls within asp placeholder

    - by alaa9jo
    I use placeholders very much in many projects,but in one of the projects I was asked to reset the controls within a specific placeholder to their original state after the user has finished from inserting his/her data. As everyone of us know,to keep the controls within a placeholder from disappearing after postbacks you have to recreate them,we add such a code in i.e. page_load,the controls will be recreated and their values will be loaded from viewstate (for some of them like textbox,checkboxs,..etc) automatically,that placeholder contains only textboxs so what I need is to block/ loading/clear that viewstate after inserting the data. First thought: Customizing placeholder I thought about it and tried overriding many methods but no success at all...maybe I'm missing something not sure. Second thought: recreate the controls 2 times: In page_load,I recreate the controls within that placeholder then in button click (the button that saves user's data) I recreate them once more and it worked! I just thought of sharing my experience in that case with everyone in case anyone needed it,any better suggestion(s) is welcomed.

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  • How properly perform passing operation result to View

    - by atomAltera
    I'm developing web site on self made MVC engine. I have actionController that handles operations like register, login, post submit and etc. actionController receives operation name and parameters. Of course it mast handle errors such user with same nick already exists or password is to short about which action handler have to notify user. The question is which is the best way to organize errors, such that View could easily get localized user notification message. I see two ways First one: define error constants like ERR_NICK_BUSY = '1' ERR_NICK_INVALID = '2' ... and localization map local[ERR_NICK_BUSY] = 'User with the same nick already registered' local[ERR_NICK_INVALID ] = 'Nick, you entered is invalid' ... And second one: define abstract constants like ERR_FIELD_BUSY = '1' ERR_FIELD_INVALID = '2' ... and pass them with field name. In this case localization looks like local['nick_'+ERR_FIELD_BUSY] = 'User with the same nick already registered' ... I don't like both this methods. Can you advise something else?

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  • How do I set a touch listener in a child scene in AndEngine?

    - by Siddharth
    In my game, I want to implement touch listener for my child scene objects. Basically I tried all the possible way to implement this that I have usually done for my normal scenes, but those methods do not work here. Could somebody provide some guidance for setting touch area listener in child scene? Here is my code: menuScene.setTouchAreaBindingEnabled(true); menuScene.registerTouchArea(resumeButtonSprite); menuScene.registerTouchArea(retryButtonSprite); menuScene.registerTouchArea(exitButtonSprite); menuScene.setOnAreaTouchListener(new IOnAreaTouchListener() { @Override public boolean onAreaTouched(TouchEvent pSceneTouchEvent, ITouchArea pTouchArea, float pTouchAreaLocalX, float pTouchAreaLocalY) { System.out.println("Touch"); return true; } }); In this code, menuScene was a child scene activity. Also after research I found that my engine was stopped while the child scene was activated so the touch event is not detected. I want to implement a pause menu in my game so any desirable solution for a pause menu implementation would help.

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  • Microsoft Unity 2.0 Released

    - by shiju
    Microsoft's dependency injection framework Unity Application Block (Unity) has reached version 2.0. The release available on Codeplex at http://unity.codeplex.com/ Unity 2.0  Change LogRelease Notes - Unity 2 for DesktopRelease Notes - Unity 2 for SilverlightOfficial Download - Unity 2.0Official Download - Unity 2.0 for SilverlightAdditional Materials DownloadMigration GuideVideos UnityContainer Fluent InterfaceUnity 2.0 provides a fluent interface for type configuration. Now you can call all the methods in a single statement, as shown in the following code.  IUnityContainer container = new UnityContainer() .RegisterType<IFormsAuthentication, FormsAuthenticationService>() .RegisterType<IMembershipService, AccountMembershipService>() .RegisterInstance<MembershipProvider>(Membership.Provider) .RegisterType<IDinnerRepository, DinnerRepository>();    

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  • Simple Preferred time control using silverlight 3.

    - by mohanbrij
    Here I am going to show you a simple preferred time control, where you can select the day of the week and the time of the day. This can be used in lots of place where you may need to display the users preferred times. Sample screenshot is attached below. This control is developed using Silverlight 3 and VS2008, I am also attaching the source code with this post. This is a very basic example. You can download and customize if further for your requirement if you want. I am trying to explain in few words how this control works and what are the different ways in which you can customize it further. File: PreferredTimeControl.xaml, in this file I have just hardcoded the controls and their positions which you can see in the screenshot above. In this example, to change the start day of the week and time, you will have to go and change the design in XAML file, its not controlled by your properties or implementation classes. You can also customize it to change the start day of the week, Language, Display format, styles, etc, etc. File: PreferredTimeControl.xaml.cs, In this control using the code below, first I am taking all the checkbox from my form and store it in the Global Variable, which I can use across my page. List<CheckBox> checkBoxList; #region Constructor public PreferredTimeControl() { InitializeComponent(); GetCheckboxes();//Keep all the checkbox in List in the Load itself } #endregion #region Helper Methods private List<CheckBox> GetCheckboxes() { //Get all the CheckBoxes in the Form checkBoxList = new List<CheckBox>(); foreach (UIElement element in LayoutRoot.Children) { if (element.GetType().ToString() == "System.Windows.Controls.CheckBox") { checkBoxList.Add(element as CheckBox); } } return checkBoxList; } Then I am exposing the two methods which you can use in the container form to get and set the values in this controls. /// <summary> /// Set the Availability on the Form, with the Provided Timings /// </summary> /// <param name="selectedTimings">Provided timings comes from the DB in the form 11,12,13....37 /// Where 11 refers to Monday Morning, 12 Tuesday Morning, etc /// Here 1, 2, 3 is for Morning, Afternoon and Evening respectively, and for weekdays /// 1,2,3,4,5,6,7 where 1 is for Monday, Tuesday, Wednesday, Thrusday, Friday, Saturday and Sunday respectively /// So if we want Monday Morning, we can can denote it as 11, similarly for Saturday Evening we can write 36, etc /// </param> public void SetAvailibility(string selectedTimings) { foreach (CheckBox chk in checkBoxList) { chk.IsChecked = false; } if (!String.IsNullOrEmpty(selectedTimings)) { string[] selectedString = selectedTimings.Split(','); foreach (string selected in selectedString) { foreach (CheckBox chk in checkBoxList) { if (chk.Tag.ToString() == selected) { chk.IsChecked = true; } } } } } /// <summary> /// Gets the Availibility from the selected checkboxes /// </summary> /// <returns>String in the format of 11,12,13...41,42...31,32...37</returns> public string GetAvailibility() { string selectedText = string.Empty; foreach (CheckBox chk in GetCheckboxes()) { if (chk.IsChecked == true) { selectedText = chk.Tag.ToString() + "," + selectedText; } } return selectedText; }   In my example I am using the matrix format for Day and Time, for example Monday=1, Tuesday=2, Wednesday=3, Thursday = 4, Friday = 5, Saturday = 6, Sunday=7. And Morning = 1, Afternoon =2, Evening = 3. So if I want to represent Morning-Monday I will have to represent it as 11, Afternoon-Tuesday as 22, Morning-Wednesday as 13, etc. And in the other way to set the values in the control I am passing the values in the control in the same format as preferredTimeControl.SetAvailibility("11,12,13,16,23,22"); So this will set the checkbox value for Morning-Monday, Morning-Tuesday, Morning-Wednesday, Morning-Saturday, Afternoon of Tuesday and Afternoon of Wednesday. To implement this control, first I have to import this control in xmlns namespace as xmlns:controls="clr-namespace:PreferredTimeControlApp" and finally put in your page wherever you want, <Grid x:Name="LayoutRoot" Style="{StaticResource LayoutRootGridStyle}"> <Border x:Name="ContentBorder" Style="{StaticResource ContentBorderStyle}"> <controls:PreferredTimeControl x:Name="preferredTimeControl"></controls:PreferredTimeControl> </Border> </Grid> And in the code behind you can just include this code: private void InitializeControl() { preferredTimeControl.SetAvailibility("11,12,13,16,23,22"); } And you are ready to go. For more details you can refer to my code attached. I know there can be even simpler and better way to do this. Let me know if any other ideas. Sorry, Guys Still I have used Silverlight 3 and VS2008, as from the system I am uploading this is still not upgraded, but still you can use the same code with Silverlight 4 and VS2010 without any changes. May be just it will ask you to upgrade your project which will take care of rest. Download Source Code.   Thanks ~Brij

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  • How to Share Files Online with Ubuntu One

    - by Chris Hoffman
    Ubuntu One, Ubuntu’s built-in cloud file storage service, allows you to make files publically available online or share them privately with others. You can share files over the Internet right from Ubuntu’s file browser. Ubuntu One has two file-sharing methods: Publish, which makes a file publically available on the web to anyone who knows its address, and Share, which shares a folder with other Ubuntu One users. HTG Explains: What Is Two-Factor Authentication and Should I Be Using It? HTG Explains: What Is Windows RT and What Does It Mean To Me? HTG Explains: How Windows 8′s Secure Boot Feature Works & What It Means for Linux

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  • Ubuntu Desktop Password

    - by doug
    I inherited a machine with Ubuntu desktop installed. It has a password in place and I have no idea what the password may be. I cannot get to the command line to use the methods I have found online. No matter how many times I press "Shift" during the boot process it still goes all the way to the desktop login. I never see grub. I am not sure which version I have but I think may be 9 or 10. Thanks Doug

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  • Hide 'Your profile could not be opened correctly'

    - by B. Roland
    Hello! I have a small public internet cafe, with Ubuntu 10.04 and 10.10. I'm using Google Chrome 7.0.517.44 (64615), with AutoScroll - Version: 2.7.5; AdBlock is removed because of high CPU loads, and unconfortable speed of machine. "Your profile could not be opened correctly" error is displayed: This image is only an illustration. The reason is that I changed permissions of some config files, to don't remember the history, there are no setting in options, to don't use history. I've been removed write permission to: ~/.config/google-chrome$ find . -group nopasswdlogin ./Default/Archived History ./Default/History ./Default/Visited Links When I solved all of my problem, I'll remove some other write permission, this is a public place. What methods are known to HIDE this message? Thanks!

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  • Low level Linux graphics

    - by math4tots
    For educational purposes, I'd like to write an application on a Linux environment that can process keyboard events and draw graphics without huge dependencies like X or SDL. I presume that this must be possible, because X and SDL are just programs themselves, so they must rely on other methods inherent to the environment. Is this understanding correct? If so, where might I learn to write such a program? My limited experience tells me that it would involve making calls to the kernel, and/or writing to special files; however, I haven't been able to find any tutorials on the matter (I am not even sure what to Google). Also, in case it is relevant, I am running Debian Squeeze on Virtualbox. I have used a netinst cd without networking, so there isn't much installed on it currently. I will install gcc, but I am hoping I can get by with nothing more.

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  • Addressing a variable in VB

    - by Jeff
    Why doesn't Visual Basic.NET have the addressof operator like C#? In C#, one can int i = 123; int* addr = &i; But VB has no equivalent counter part. It seems like it should be important. UPDATE Since there's some interest, Im copying my response to Strilanc below. The case I ran into didnt necessitate pointers by any means, but I was trying to trouble shoot a unit test that was failing and there was some confusion over whether or not an object being used at one point in the stack was the same object as an object several methods away.

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  • APress Deal of the Day 10/August/2014 - Pro ASP.NET Web API Security

    - by TATWORTH
    Originally posted on: http://geekswithblogs.net/TATWORTH/archive/2014/08/10/apress-deal-of-the-day-10august2014---pro-asp.net-web.aspxToday’s $10 Deal of the Day from APress at http://www.apress.com/9781430257820 is Pro ASP.NET Web API Security. “ASP.NET Web API is a key part of ASP.NET MVC 4. It has become the platform of choice for building RESTful services. Securing ASP.NET Web API applications requires a move away from traditional WCF-based techniques in favor of new SOAP-less methods. The evaluation, selection and analysis of these new techniques is the focus of this book.”

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  • Googlebot fetches my pages very frequent, rel-nofollow, meta-noindex or robots.txt-disallow

    - by trante
    Googlebot fetches pages in my site very frequently. And this slowens my website. I don't want Googlebot to crawl too frequent. I decreased crawl rate from Google webmaster tools. But I'm supposing to use these three tools: Adding rel="nofollow" to my inner pages. So Googlebot won't crawl and index them. Adding meta tag "noindex" so Google will remove this page from index and won't get it again. Adding Disallow: /mySomeFolder/ to robots.txt and Googlebot won't crawl that pages. I'm planning to use these methods for my 56.000 pages, except the most important 6-7 pages. Which method would you prefer and what would be disadvantages or advantages ? Or won't it change my website speed etc..

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  • Telerik Releases the Data Service Wizard

    After a great beta cycle, Telerik is proud to announce today the commercial availability of the OpenAccess Data Service Wizard. You can download it and install it with Telerik OpenAccess Q1 2010 for both Visual Studio 2008 and 2010 RTM. If you are new to the Data Service Wizard, it is a great tool that will allow you to point a wizard at your OpenAccess generated data access classes and automatically build an WCF, Astoria (WCF Data Services), REST or ATOMPub collection endpoint, complete with the CRUD methods if applicable. If you are familiar with the Data Service Wizard already, there will be two new surprises in the release version. If you generated a domain model with the new OpenAccess Visual Entity Designer, you have only one file added to your project, mydomainmodel.rlinq for example. The first surprise of the new Data Service Wizard is that if you right click on the domain model in Visual Studio, ...Did you know that DotNetSlackers also publishes .net articles written by top known .net Authors? We already have over 80 articles in several categories including Silverlight. Take a look: here.

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  • Complexity of a web application

    - by Dominik G
    I am currently writing my Master's Thesis on maintainability of a web application. I found some methods like the "Maintainability Index" by Coleman et.al. or the "Software Maintainability Index" by Muthanna et.al. For both of them one needs to calculate the cyclomatic complexity. So my question is: Is it possible to measure the cyclomatic complexity of a web application? In my opinion there are three parts to a web application: Server code (PHP, C#, Python, Perl, etc.) Client code (JavaScript) HTML (links and forms as operators, GET-parameters and form fields as operands!?) What do you think? Is there another point of view on the complexity of web application? Did I miss something?

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  • libssh2 and simultaneous connections

    - by Florian Margaine
    I'm writing a node.js C++ module using the C library libssh2. The module is supposed to be a bridge to connect to SSH over HTTPS. Right now, I'm still in the design/learning phase of v8 API and C++, and I have a design question: libssh2 is a C library, all its methods are global. From what I see in the examples, libssh2 can only handle one connection at a time. If I want to allow simultaneous connections to different SSH servers, do I have to fork a process to completely separate the libssh2 "instances", or is forking a thread enough? I don't know enough of the separation limit used there. Any idea on how to handle this is appreciated.

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  • Gradual approaches to dependency injection

    - by JW01
    I'm working on making my classes unit-testable, using dependency injection. But some of these classes have a lot of clients, and I'm not ready to refactor all of them to start passing in the dependencies yet. So I'm trying to do it gradually; keeping the default dependencies for now, but allowing them to be overridden for testing. One approach I'm conisdering is just moving all the "new" calls into their own methods, e.g.: public MyObject createMyObject(args) { return new MyObject(args); } Then in my unit tests, I can just subclass this class, and override the create functions, so they create fake objects instead. Is this a good approach? Are there any disadvantages? More generally, is it okay to have hard-coded dependencies, as long as you can replace them for testing? I know the preferred approach is to explicitly require them in the constructor, and I'd like to get there eventually. But I'm wondering if this is a good first step.

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  • Ubuntu Extras keyring error

    - by Pawan Neupane
    Recently I got lots of GPG errors and tried the following methods at various stages: sudo apt-key adv --keyserver keyserver.ubuntu.com --recv-keys 3E5C1192 sudo apt-get install -reinstall ubuntu-extras-keyring (For Ubuntu Extras only) gpg –keyserver keyserver.ubuntu.com –recv 3E5C1192 gpg –export –armor 3E5C1192 | sudo apt-key add - sudo apt-get update sudo aptitude -o Acquire::http::No-Cache=True -o Acquire::BrokenProxy=true update sudo -i apt-get clean cd /var/lib/apt mv lists lists.old mkdir -p lists/partial apt-get clean apt-get update I again got BADSIG error for extras.ubuntu.com today. So, I'm really at a loss what's causing this error to occur time and again. I really want to solve this problem once and for all.

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  • PTLQueue : a scalable bounded-capacity MPMC queue

    - by Dave
    Title: Fast concurrent MPMC queue -- I've used the following concurrent queue algorithm enough that it warrants a blog entry. I'll sketch out the design of a fast and scalable multiple-producer multiple-consumer (MPSC) concurrent queue called PTLQueue. The queue has bounded capacity and is implemented via a circular array. Bounded capacity can be a useful property if there's a mismatch between producer rates and consumer rates where an unbounded queue might otherwise result in excessive memory consumption by virtue of the container nodes that -- in some queue implementations -- are used to hold values. A bounded-capacity queue can provide flow control between components. Beware, however, that bounded collections can also result in resource deadlock if abused. The put() and take() operators are partial and wait for the collection to become non-full or non-empty, respectively. Put() and take() do not allocate memory, and are not vulnerable to the ABA pathologies. The PTLQueue algorithm can be implemented equally well in C/C++ and Java. Partial operators are often more convenient than total methods. In many use cases if the preconditions aren't met, there's nothing else useful the thread can do, so it may as well wait via a partial method. An exception is in the case of work-stealing queues where a thief might scan a set of queues from which it could potentially steal. Total methods return ASAP with a success-failure indication. (It's tempting to describe a queue or API as blocking or non-blocking instead of partial or total, but non-blocking is already an overloaded concurrency term. Perhaps waiting/non-waiting or patient/impatient might be better terms). It's also trivial to construct partial operators by busy-waiting via total operators, but such constructs may be less efficient than an operator explicitly and intentionally designed to wait. A PTLQueue instance contains an array of slots, where each slot has volatile Turn and MailBox fields. The array has power-of-two length allowing mod/div operations to be replaced by masking. We assume sensible padding and alignment to reduce the impact of false sharing. (On x86 I recommend 128-byte alignment and padding because of the adjacent-sector prefetch facility). Each queue also has PutCursor and TakeCursor cursor variables, each of which should be sequestered as the sole occupant of a cache line or sector. You can opt to use 64-bit integers if concerned about wrap-around aliasing in the cursor variables. Put(null) is considered illegal, but the caller or implementation can easily check for and convert null to a distinguished non-null proxy value if null happens to be a value you'd like to pass. Take() will accordingly convert the proxy value back to null. An advantage of PTLQueue is that you can use atomic fetch-and-increment for the partial methods. We initialize each slot at index I with (Turn=I, MailBox=null). Both cursors are initially 0. All shared variables are considered "volatile" and atomics such as CAS and AtomicFetchAndIncrement are presumed to have bidirectional fence semantics. Finally T is the templated type. I've sketched out a total tryTake() method below that allows the caller to poll the queue. tryPut() has an analogous construction. Zebra stripping : alternating row colors for nice-looking code listings. See also google code "prettify" : https://code.google.com/p/google-code-prettify/ Prettify is a javascript module that yields the HTML/CSS/JS equivalent of pretty-print. -- pre:nth-child(odd) { background-color:#ff0000; } pre:nth-child(even) { background-color:#0000ff; } border-left: 11px solid #ccc; margin: 1.7em 0 1.7em 0.3em; background-color:#BFB; font-size:12px; line-height:65%; " // PTLQueue : Put(v) : // producer : partial method - waits as necessary assert v != null assert Mask = 1 && (Mask & (Mask+1)) == 0 // Document invariants // doorway step // Obtain a sequence number -- ticket // As a practical concern the ticket value is temporally unique // The ticket also identifies and selects a slot auto tkt = AtomicFetchIncrement (&PutCursor, 1) slot * s = &Slots[tkt & Mask] // waiting phase : // wait for slot's generation to match the tkt value assigned to this put() invocation. // The "generation" is implicitly encoded as the upper bits in the cursor // above those used to specify the index : tkt div (Mask+1) // The generation serves as an epoch number to identify a cohort of threads // accessing disjoint slots while s-Turn != tkt : Pause assert s-MailBox == null s-MailBox = v // deposit and pass message Take() : // consumer : partial method - waits as necessary auto tkt = AtomicFetchIncrement (&TakeCursor,1) slot * s = &Slots[tkt & Mask] // 2-stage waiting : // First wait for turn for our generation // Acquire exclusive "take" access to slot's MailBox field // Then wait for the slot to become occupied while s-Turn != tkt : Pause // Concurrency in this section of code is now reduced to just 1 producer thread // vs 1 consumer thread. // For a given queue and slot, there will be most one Take() operation running // in this section. // Consumer waits for producer to arrive and make slot non-empty // Extract message; clear mailbox; advance Turn indicator // We have an obvious happens-before relation : // Put(m) happens-before corresponding Take() that returns that same "m" for T v = s-MailBox if v != null : s-MailBox = null ST-ST barrier s-Turn = tkt + Mask + 1 // unlock slot to admit next producer and consumer return v Pause tryTake() : // total method - returns ASAP with failure indication for auto tkt = TakeCursor slot * s = &Slots[tkt & Mask] if s-Turn != tkt : return null T v = s-MailBox // presumptive return value if v == null : return null // ratify tkt and v values and commit by advancing cursor if CAS (&TakeCursor, tkt, tkt+1) != tkt : continue s-MailBox = null ST-ST barrier s-Turn = tkt + Mask + 1 return v The basic idea derives from the Partitioned Ticket Lock "PTL" (US20120240126-A1) and the MultiLane Concurrent Bag (US8689237). The latter is essentially a circular ring-buffer where the elements themselves are queues or concurrent collections. You can think of the PTLQueue as a partitioned ticket lock "PTL" augmented to pass values from lock to unlock via the slots. Alternatively, you could conceptualize of PTLQueue as a degenerate MultiLane bag where each slot or "lane" consists of a simple single-word MailBox instead of a general queue. Each lane in PTLQueue also has a private Turn field which acts like the Turn (Grant) variables found in PTL. Turn enforces strict FIFO ordering and restricts concurrency on the slot mailbox field to at most one simultaneous put() and take() operation. PTL uses a single "ticket" variable and per-slot Turn (grant) fields while MultiLane has distinct PutCursor and TakeCursor cursors and abstract per-slot sub-queues. Both PTL and MultiLane advance their cursor and ticket variables with atomic fetch-and-increment. PTLQueue borrows from both PTL and MultiLane and has distinct put and take cursors and per-slot Turn fields. Instead of a per-slot queues, PTLQueue uses a simple single-word MailBox field. PutCursor and TakeCursor act like a pair of ticket locks, conferring "put" and "take" access to a given slot. PutCursor, for instance, assigns an incoming put() request to a slot and serves as a PTL "Ticket" to acquire "put" permission to that slot's MailBox field. To better explain the operation of PTLQueue we deconstruct the operation of put() and take() as follows. Put() first increments PutCursor obtaining a new unique ticket. That ticket value also identifies a slot. Put() next waits for that slot's Turn field to match that ticket value. This is tantamount to using a PTL to acquire "put" permission on the slot's MailBox field. Finally, having obtained exclusive "put" permission on the slot, put() stores the message value into the slot's MailBox. Take() similarly advances TakeCursor, identifying a slot, and then acquires and secures "take" permission on a slot by waiting for Turn. Take() then waits for the slot's MailBox to become non-empty, extracts the message, and clears MailBox. Finally, take() advances the slot's Turn field, which releases both "put" and "take" access to the slot's MailBox. Note the asymmetry : put() acquires "put" access to the slot, but take() releases that lock. At any given time, for a given slot in a PTLQueue, at most one thread has "put" access and at most one thread has "take" access. This restricts concurrency from general MPMC to 1-vs-1. We have 2 ticket locks -- one for put() and one for take() -- each with its own "ticket" variable in the form of the corresponding cursor, but they share a single "Grant" egress variable in the form of the slot's Turn variable. Advancing the PutCursor, for instance, serves two purposes. First, we obtain a unique ticket which identifies a slot. Second, incrementing the cursor is the doorway protocol step to acquire the per-slot mutual exclusion "put" lock. The cursors and operations to increment those cursors serve double-duty : slot-selection and ticket assignment for locking the slot's MailBox field. At any given time a slot MailBox field can be in one of the following states: empty with no pending operations -- neutral state; empty with one or more waiting take() operations pending -- deficit; occupied with no pending operations; occupied with one or more waiting put() operations -- surplus; empty with a pending put() or pending put() and take() operations -- transitional; or occupied with a pending take() or pending put() and take() operations -- transitional. The partial put() and take() operators can be implemented with an atomic fetch-and-increment operation, which may confer a performance advantage over a CAS-based loop. In addition we have independent PutCursor and TakeCursor cursors. Critically, a put() operation modifies PutCursor but does not access the TakeCursor and a take() operation modifies the TakeCursor cursor but does not access the PutCursor. This acts to reduce coherence traffic relative to some other queue designs. It's worth noting that slow threads or obstruction in one slot (or "lane") does not impede or obstruct operations in other slots -- this gives us some degree of obstruction isolation. PTLQueue is not lock-free, however. The implementation above is expressed with polite busy-waiting (Pause) but it's trivial to implement per-slot parking and unparking to deschedule waiting threads. It's also easy to convert the queue to a more general deque by replacing the PutCursor and TakeCursor cursors with Left/Front and Right/Back cursors that can move either direction. Specifically, to push and pop from the "left" side of the deque we would decrement and increment the Left cursor, respectively, and to push and pop from the "right" side of the deque we would increment and decrement the Right cursor, respectively. We used a variation of PTLQueue for message passing in our recent OPODIS 2013 paper. ul { list-style:none; padding-left:0; padding:0; margin:0; margin-left:0; } ul#myTagID { padding: 0px; margin: 0px; list-style:none; margin-left:0;} -- -- There's quite a bit of related literature in this area. I'll call out a few relevant references: Wilson's NYU Courant Institute UltraComputer dissertation from 1988 is classic and the canonical starting point : Operating System Data Structures for Shared-Memory MIMD Machines with Fetch-and-Add. Regarding provenance and priority, I think PTLQueue or queues effectively equivalent to PTLQueue have been independently rediscovered a number of times. See CB-Queue and BNPBV, below, for instance. But Wilson's dissertation anticipates the basic idea and seems to predate all the others. Gottlieb et al : Basic Techniques for the Efficient Coordination of Very Large Numbers of Cooperating Sequential Processors Orozco et al : CB-Queue in Toward high-throughput algorithms on many-core architectures which appeared in TACO 2012. Meneghin et al : BNPVB family in Performance evaluation of inter-thread communication mechanisms on multicore/multithreaded architecture Dmitry Vyukov : bounded MPMC queue (highly recommended) Alex Otenko : US8607249 (highly related). John Mellor-Crummey : Concurrent queues: Practical fetch-and-phi algorithms. Technical Report 229, Department of Computer Science, University of Rochester Thomasson : FIFO Distributed Bakery Algorithm (very similar to PTLQueue). Scott and Scherer : Dual Data Structures I'll propose an optimization left as an exercise for the reader. Say we wanted to reduce memory usage by eliminating inter-slot padding. Such padding is usually "dark" memory and otherwise unused and wasted. But eliminating the padding leaves us at risk of increased false sharing. Furthermore lets say it was usually the case that the PutCursor and TakeCursor were numerically close to each other. (That's true in some use cases). We might still reduce false sharing by incrementing the cursors by some value other than 1 that is not trivially small and is coprime with the number of slots. Alternatively, we might increment the cursor by one and mask as usual, resulting in a logical index. We then use that logical index value to index into a permutation table, yielding an effective index for use in the slot array. The permutation table would be constructed so that nearby logical indices would map to more distant effective indices. (Open question: what should that permutation look like? Possibly some perversion of a Gray code or De Bruijn sequence might be suitable). As an aside, say we need to busy-wait for some condition as follows : "while C == 0 : Pause". Lets say that C is usually non-zero, so we typically don't wait. But when C happens to be 0 we'll have to spin for some period, possibly brief. We can arrange for the code to be more machine-friendly with respect to the branch predictors by transforming the loop into : "if C == 0 : for { Pause; if C != 0 : break; }". Critically, we want to restructure the loop so there's one branch that controls entry and another that controls loop exit. A concern is that your compiler or JIT might be clever enough to transform this back to "while C == 0 : Pause". You can sometimes avoid this by inserting a call to a some type of very cheap "opaque" method that the compiler can't elide or reorder. On Solaris, for instance, you could use :"if C == 0 : { gethrtime(); for { Pause; if C != 0 : break; }}". It's worth noting the obvious duality between locks and queues. If you have strict FIFO lock implementation with local spinning and succession by direct handoff such as MCS or CLH,then you can usually transform that lock into a queue. Hidden commentary and annotations - invisible : * And of course there's a well-known duality between queues and locks, but I'll leave that topic for another blog post. * Compare and contrast : PTLQ vs PTL and MultiLane * Equivalent : Turn; seq; sequence; pos; position; ticket * Put = Lock; Deposit Take = identify and reserve slot; wait; extract & clear; unlock * conceptualize : Distinct PutLock and TakeLock implemented as ticket lock or PTL Distinct arrival cursors but share per-slot "Turn" variable provides exclusive role-based access to slot's mailbox field put() acquires exclusive access to a slot for purposes of "deposit" assigns slot round-robin and then acquires deposit access rights/perms to that slot take() acquires exclusive access to slot for purposes of "withdrawal" assigns slot round-robin and then acquires withdrawal access rights/perms to that slot At any given time, only one thread can have withdrawal access to a slot at any given time, only one thread can have deposit access to a slot Permissible for T1 to have deposit access and T2 to simultaneously have withdrawal access * round-robin for the purposes of; role-based; access mode; access role mailslot; mailbox; allocate/assign/identify slot rights; permission; license; access permission; * PTL/Ticket hybrid Asymmetric usage ; owner oblivious lock-unlock pairing K-exclusion add Grant cursor pass message m from lock to unlock via Slots[] array Cursor performs 2 functions : + PTL ticket + Assigns request to slot in round-robin fashion Deconstruct protocol : explication put() : allocate slot in round-robin fashion acquire PTL for "put" access store message into slot associated with PTL index take() : Acquire PTL for "take" access // doorway step seq = fetchAdd (&Grant, 1) s = &Slots[seq & Mask] // waiting phase while s-Turn != seq : pause Extract : wait for s-mailbox to be full v = s-mailbox s-mailbox = null Release PTL for both "put" and "take" access s-Turn = seq + Mask + 1 * Slot round-robin assignment and lock "doorway" protocol leverage the same cursor and FetchAdd operation on that cursor FetchAdd (&Cursor,1) + round-robin slot assignment and dispersal + PTL/ticket lock "doorway" step waiting phase is via "Turn" field in slot * PTLQueue uses 2 cursors -- put and take. Acquire "put" access to slot via PTL-like lock Acquire "take" access to slot via PTL-like lock 2 locks : put and take -- at most one thread can access slot's mailbox Both locks use same "turn" field Like multilane : 2 cursors : put and take slot is simple 1-capacity mailbox instead of queue Borrow per-slot turn/grant from PTL Provides strict FIFO Lock slot : put-vs-put take-vs-take at most one put accesses slot at any one time at most one put accesses take at any one time reduction to 1-vs-1 instead of N-vs-M concurrency Per slot locks for put/take Release put/take by advancing turn * is instrumental in ... * P-V Semaphore vs lock vs K-exclusion * See also : FastQueues-excerpt.java dice-etc/queue-mpmc-bounded-blocking-circular-xadd/ * PTLQueue is the same as PTLQB - identical * Expedient return; ASAP; prompt; immediately * Lamport's Bakery algorithm : doorway step then waiting phase Threads arriving at doorway obtain a unique ticket number Threads enter in ticket order * In the terminology of Reed and Kanodia a ticket lock corresponds to the busy-wait implementation of a semaphore using an eventcount and a sequencer It can also be thought of as an optimization of Lamport's bakery lock was designed for fault-tolerance rather than performance Instead of spinning on the release counter, processors using a bakery lock repeatedly examine the tickets of their peers --

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  • A Semantic Model For Html: TagBuilder and HtmlTags

    - by Ryan Ohs
    In this post I look into the code smell that is HTML literals and show how we can refactor these pesky strings into a friendlier and more maintainable model.   The Problem When I started writing MVC applications, I quickly realized that I built a lot of my HTML inside HtmlHelpers. As I did this, I ended up moving quite a bit of HTML into string literals inside my helper classes. As I wanted to add more attributes (such as classes) to my tags, I needed to keep adding overloads to my helpers. A good example of this end result is the default html helpers that come with the MVC framework. Too many overloads make me crazy! The problem with all these overloads is that they quickly muck up the API and nobody can remember exactly what order the parameters go in. I've seen many presenters (including members of the ASP.NET MVC team!) stumble before realizing that their view wasn't compiling because they needed one more null parameter in the call to Html.ActionLink(). What if instead of writing Html.ActionLink("Edit", "Edit", null, new { @class = "navigation" }) we could do Html.LinkToAction("Edit").Text("Edit").AddClass("navigation") ? Wouldn't that be much easier to remember and understand?  We can do this if we introduce a semantic model for building our HTML.   What is a Semantic Model? According to Martin Folwer, "a semantic model is an in-memory representation, usually an object model, of the same subject that the domain specific language describes." In our case, the model would be a set of classes that know how to render HTML. By using a semantic model we can free ourselves from dealing with strings and instead output the HTML (typically via ToString()) once we've added all the elements and attributes we desire to the model. There are two primary semantic models available in ASP.NET MVC: MVC 2.0's TagBuilder and FubuMVC's HtmlTags.   TagBuilder TagBuilder is the html builder that is available in ASP.NET MVC 2.0. I'm not a huge fan but it gets the job done -- for simple jobs.  Here's an overview of how to use TagBuilder. See my Tips section below for a few comments on that example. The disadvantage of TagBuilder is that unless you wrap it up with our own classes, you still have to write the actual tag name over and over in your code. eg. new TagBuilder("div") instead of new DivTag(). I also think it's method names are a little too long. Why not have AddClass() instead of AddCssClass() or Text() instead of SetInnerText()? What those methods are doing should be pretty obvious even in the short form. I also don't like that it wants to generate an id attribute from your input instead of letting you set it yourself using external conventions. (See GenerateId() and IdAttributeDotReplacement)). Obviously these come from Microsoft's default approach to MVC but may not be optimal for all programmers.   HtmlTags HtmlTags is in my opinion the much better option for generating html in ASP.NET MVC. It was actually written as a part of FubuMVC but is available as a stand alone library. HtmlTags provides a much cleaner syntax for writing HTML. There are classes for most of the major tags and it's trivial to create additional ones by inheriting from HtmlTag. There are also methods on each tag for the common attributes. For instance, FormTag has an Action() method. The SelectTag class allows you to set the default option or first option independent from adding other options. With TagBuilder there isn't even an abstraction for building selects! The project is open source and always improving. I'll hopefully find time to submit some of my own enhancements soon.   Tips 1) It's best not to have insanely overloaded html helpers. Use fluent builders. 2) In html helpers, return the TagBuilder/tag itself (not a string!) so that you can continue to add attributes outside the helper; see my first sample above. 3) Create a static entry point into your builders. I created a static Tags class that gives me access all the HtmlTag classes I need. This way I don't clutter my code with "new" keywords. eg. Tags.Div returns a new DivTag instance. 4) If you find yourself doing something a lot, create an extension method for it. I created a Nest() extension method that reads much more fluently than the AddChildren() method. It also accepts a params array of tags so I can very easily nest many children.   I hope you have found this post helpful. Join me in my war against HTML literals! I’ll have some more samples of how I use HtmlTags in future posts.

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  • Day 4 - Game Sprites In Action

    - by dapostolov
    Yesterday I drew an image on the screen. Most exciting, but ... I spent more time blogging about it then actual coding. So this next little while I'm going to streamline my game and research and simply post key notes. Quick notes on the last session: The most important thing I wanted to point out were the following methods:           spriteBatch.Begin(SpriteBlendMode.AlphaBlend);           spriteBatch.Draw(sprite, position, Color.White);           spriteBatch.End(); The spriteBatch object is used to draw Textures and a 2D texture is called a Sprite A texture is generally an image, which is called an Asset in XNA The Draw Method in the Game1.cs is looped (until exit) and utilises the spriteBatch object to draw a Scene To begin drawing a Scene you call the Begin Method. To end a Scene you call the End Method. And to place an image on the Scene you call the Draw method. The most simple implementation of the draw method is:           spriteBatch.Draw(sprite, position, Color.White); 1) sprite - the 2D texture you loaded to draw 2) position - the 2d vector, a set of x & y coordinates 3) Color.White - the tint to apply to the texture, in this case, white light = nothing, nada, no tint. Game Sprites In Action! Today, I played around with Draw methods to get comfortable with their "quirks". The following is an example of the above draw method, but with more parameters available for us to use. Let's investigate!             spriteBatch.Draw(sprite, position2, null, Color.White, MathHelper.ToRadians(45.0f), new Vector2(sprite.Width / 2, sprite.Height / 2), 1.0F, SpriteEffects.None, 0.0F); The parameters (in order): 1) sprite  the texture to display 2) position2 the position on the screen / scene this can also be a rectangle 3) null the portion of the image to display within an image null = display full image this is generally used for animation strips / grids (more on this below) 4) Color.White Texture tinting White = no tint 5) MathHelper.ToRadians(45.0f) rotation of the object, in this case 45 degrees rotates from the set plotting point. 6) new Vector(0,0) the plotting point in this case the top left corner the image will rotate from the top left of the texture in the code above, the point is set to the middle of the image. 7) 1.0f Image scaling (1x) 8) SpriteEffects.None you can flip the image horizontally or vertically 9) 0.0f The z index of the image. 0 = closer, 1 behind? And playing around with different combinations I was able to come up with the following whacky display:   Checking off Yesterdays Intention List: learn game development terminology (in progress) - We learned sprite, scene, texture, and asset. how to place and position (rotate) a static image on the screen (completed) - The thing to note was, it's was in radians and I found a cool helper method to convert degrees into radians. Also, the image rotates from it's specified point. how to layer static images on the screen (completed) - I couldn't seem to get the zIndex working, but one things for sure, the order you draw the image in also determines how it is rendered on the screen. understand image scaling (in progress) - I'm not sure I have this fully covered, but for the most part plug a number in the scaling field and the image grows / shrinks accordingly. can we reuse images? (completed) - yes, I loaded one image and plotted the bugger all over the screen. understand how framerate is handled in XNA (in progress) - I hacked together some code to display the framerate each second. A framerate of 60 appears to be the standard. Interesting to note, the GameTime object does provide you with some cool timing capabilities, such as...is the game running slow? Need to investigate this down the road. how to display text , basic shapes, and colors on the screen (in progress) - i got text rendered on the screen, and i understand containing rectangles. However, I didn't display "shapes" & "colors" how to interact with an image (collision of user input?) (todo) how to animate an image and understand basic animation techniques (in progress) - I was able to create a stripe animation of numbers ranging from 1 - 4, each block was 40 x 40 pixles for a total stripe size of 160 x 40. Using the portion (source Rectangle) parameter, i limited this display to each section at varying intervals. It was interesting to note my first implementation animated at rocket speed. I then tried to create a smoother animation by limiting the redraw capacity, which seemed to work. I guess a little more research will have to be put into this for animating characters / scenes. how to detect colliding images or screen edges (todo) - but the rectangle object can detect collisions I believe. how to manipulate the image, lets say colors, stretching (in progress) - I haven't figured out how to modify a specific color to be another color, but the tinting parameter definately could be used. As for stretching, use the rectangle object as the positioning and the image will stretch to fit! how to focus on a segment of an image...like only displaying a frame on a film reel (completed) - as per basic animation techniques what's the best way to manage images (compression, storage, location, prevent artwork theft, etc.) (todo) Tomorrows Intention Tomorrow I am going to take a stab at rendering a game menu and from there I'm going to investigate how I can improve upon the code and techniques. Intention List: Render a menu, fancy or not Show the mouse cursor Hook up click event A basic animation of somesort Investigate image / menu techniques D.

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  • how to call wcf service from another wcf service or class library? (5 replies)

    Hi! I??m having problem consuming a WCF Service. To call this Service, I created my own WCF Service with VS2008 own template. Then I added a Service Reference to the WCF Service to consume. So far so good, the service shows up in the Solution Explorer and all methods as well. Then I Created a Class to call the Service from my own WCF Service. And everytime I try to create an object I get the same ...

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  • Turn-based Strategy Loop

    - by Djentleman
    I'm working on a strategy game. It's turn-based and card-based (think Dominion-style), done in a client, with eventual AI in the works. I've already implemented almost all of the game logic (methods for calculations and suchlike) and I'm starting to work on the actual game loop. What is the "best" way to implement a game loop in such a game? Should I use a simple "while gameActive" loop that keeps running until gameActive is False, with sections that wait for player input? Or should it be managed through the UI with player actions determining what happens and when? Any help is appreciated. I'm doing it in Python (for now at least) to get my Python skills up a bit, although the language shouldn't matter for this question.

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  • Some notes on Reflector 7

    - by CliveT
    Both Bart and I have blogged about some of the changes that we (and other members of the team) have made to .NET Reflector for version 7, including the new tabbed browsing model, the inclusion of Jason Haley's PowerCommands add-in and some improvements to decompilation such as handling iterator blocks. The intention of this blog post is to cover all of the main new features in one place, and to describe the three new editions of .NET Reflector 7. If you'd simply like to try out the latest version of the beta for yourself you can do so here. Three new editions .NET Reflector 7 will come in three new editions: .NET Reflector .NET Reflector VS .NET Reflector VSPro The first edition is just the standalone Windows application. The latter two editions include the Windows application, but also add the power of Reflector into Visual Studio so that you can save time switching tools and quickly get to the bottom of a debugging issue that involves third-party code. Let's take a look at some of the new features in each edition. Tabbed browsing .NET Reflector now has a tabbed browsing model, in which the individual tabs have independent histories. You can open a new tab to view the selected object by using CTRL+CLICK. I've found this really useful when I'm investigating a particular piece of code but then want to focus on some other methods that I find along the way. For version 7, we wanted to implement the basic idea of tabs to see whether it is something that users will find helpful. If it is something that enhances productivity, we will add more tab-based features in a future version. PowerCommands add-in We have also included Jason Haley's PowerCommands add-in as part of version 7. This add-in provides a number of useful commands, including support for opening .xap files and extracting the constituent assemblies, and a query editor that allows C# queries to be written and executed against the Reflector object model . All of the PowerCommands features can be turned on from the options menu. We will be really interested to see what people are finding useful for further integration into the main tool in the future. My personal favourite part of the PowerCommands add-in is the query editor. You can set up as many of your own queries as you like, but we provide 25 to get you started. These do useful things like listing all extension methods in a given assembly, and displaying other lower-level information, such as the number of times that a given method uses the box IL instruction. These queries can be extracted and then executed from the 'Run Query' context menu within the assembly explorer. Moreover, the queries can be loaded, modified, and saved using the built-in editor, allowing very specific user customization and sharing of queries. The PowerCommands add-in contains many other useful utilities. For example, you can open an item using an external application, work with enumeration bit flags, or generate assembly binding redirect files. You can see Bart's earlier post for a more complete list. .NET Reflector VS .NET Reflector VS adds a brand new Reflector object browser into Visual Studio to save you time opening .NET Reflector separately and browsing for an object. A 'Decompile and Explore' option is also added to the context menu of references in the Solution Explorer, so you don't need to leave Visual Studio to look through decompiled code. We've also added some simple navigation features to allow you to move through the decompiled code as quickly and easily as you can in .NET Reflector. When this is selected, the add-in decompiles the given assembly, Once the decompilation has finished, a clone of the Reflector assembly explorer can be used inside Visual Studio. When Reflector generates the source code, it records the location information. You can therefore navigate from the source file to other decompiled source using the 'Go To Definition' context menu item. This then takes you to the definition in another decompiled assembly. .NET Reflector VSPro .NET Reflector VSPro builds on the features in .NET Reflector VS to add the ability to debug any source code you decompile. When you decompile with .NET Reflector VSPro, a matching .pdb is generated, so you can use Visual Studio to debug the source code as if it were part of the project. You can now use all the standard debugging techniques that you are used to in the Visual Studio debugger, and step through decompiled code as if it were your own. Again, you can select assemblies for decompilation. They are then decompiled. And then you can debug as if they were one of your own source code files. The future of .NET Reflector As I have mentioned throughout this post, most of the new features in version 7 are exploratory steps and we will be watching feedback closely. Although we don't want to speculate now about any other new features or bugs that will or won't be fixed in the next few versions of .NET Reflector, Bart has mentioned in a previous post that there are lots of improvements we intend to make. We plan to do this with great care and without taking anything away from the simplicity of the core product. User experience is something that we pride ourselves on at Red Gate, and it is clear that Reflector is still a long way off our usual standards. We plan for the next few versions of Reflector to be worked on by some of our top usability specialists who have been involved with our other market-leading products such as the ANTS Profilers and SQL Compare. I re-iterate the need for the really great simple mode in .NET Reflector to remain intact regardless of any other improvements we are planning to make. I really hope that you enjoy using some of the new features in version 7 and that Reflector continues to be your favourite .NET development tool for a long time to come.

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  • How do I move the camera sideways in Libgdx?

    - by Bubblewrap
    I want to move the camera sideways (strafe). I had the following in mind, but it doesn't look like there are standard methods to achieve this in Libgdx. If I want to move the camera sideways by x, I think I need to do the following: Create a Matrix4 mat Determine the orthogonal vector v between camera.direction and camera.up Translate mat by v*x Multiply camera.position by mat Will this approach do what I think it does, and is it a good way to do it? And how can I do this in libgdx? I get "stuck" at step 2, as I have not found any standard method in Libgdx to calculate an orthogonal vector. EDIT: I think I can use camera.direction.crs(camera.up) to find v. I'll try this approach tonight and see if it works. EDIT2: I got it working and didn't need the matrix after all: Vector3 right = camera.direction.cpy().crs(camera.up).nor(); camera.position.add(right.mul(x));

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  • WPF: Timers

    - by Ilya Verbitskiy
    I believe, once your WPF application will need to execute something periodically, and today I would like to discuss how to do that. There are two possible solutions. You can use classical System.Threading.Timer class or System.Windows.Threading.DispatcherTimer class, which is the part of WPF. I have created an application to show you how to use the API.     Let’s take a look how you can implement timer using System.Threading.Timer class. First of all, it has to be initialized.   1: private Timer timer; 2:   3: public MainWindow() 4: { 5: // Form initialization code 6: 7: timer = new Timer(OnTimer, null, Timeout.InfiniteTimeSpan, Timeout.InfiniteTimeSpan); 8: }   Timer’s constructor accepts four parameters. The first one is the callback method which is executed when timer ticks. I will show it to you soon. The second parameter is a state which is passed to the callback. It is null because there is nothing to pass this time. The third parameter is the amount of time to delay before the callback parameter invokes its methods. I use System.Threading.Timeout helper class to represent infinite timeout which simply means the timer is not going to start at the moment. And the final fourth parameter represents the time interval between invocations of the methods referenced by callback. Infinite timeout timespan means the callback method will be executed just once. Well, the timer has been created. Let’s take a look how you can start the timer.   1: private void StartTimer(object sender, RoutedEventArgs e) 2: { 3: timer.Change(TimeSpan.Zero, new TimeSpan(0, 0, 1)); 4:   5: // Disable the start buttons and enable the reset button. 6: }   The timer is started by calling its Change method. It accepts two arguments: the amount of time to delay before the invoking the callback method and the time interval between invocations of the callback. TimeSpan.Zero means we start the timer immediately and TimeSpan(0, 0, 1) tells the timer to tick every second. There is one method hasn’t been shown yet. This is the callback method OnTimer which does a simple task: it shows current time in the center of the screen. Unfortunately you cannot simple write something like this:   1: clock.Content = DateTime.Now.ToString("hh:mm:ss");   The reason is Timer runs callback method on a separate thread, and it is not possible to access GUI controls from a non-GUI thread. You can avoid the problem using System.Windows.Threading.Dispatcher class.   1: private void OnTimer(object state) 2: { 3: Dispatcher.Invoke(() => ShowTime()); 4: } 5:   6: private void ShowTime() 7: { 8: clock.Content = DateTime.Now.ToString("hh:mm:ss"); 9: }   You can build similar application using System.Windows.Threading.DispatcherTimer class. The class represents a timer which is integrated into the Dispatcher queue. It means that your callback method is executed on GUI thread and you can write a code which updates your GUI components directly.   1: private DispatcherTimer dispatcherTimer; 2:   3: public MainWindow() 4: { 5: // Form initialization code 6:   7: dispatcherTimer = new DispatcherTimer { Interval = new TimeSpan(0, 0, 1) }; 8: dispatcherTimer.Tick += OnDispatcherTimer; 9: } Dispatcher timer has nicer and cleaner API. All you need is to specify tick interval and Tick event handler. The you just call Start method to start the timer.   private void StartDispatcher(object sender, RoutedEventArgs e) { dispatcherTimer.Start(); // Disable the start buttons and enable the reset button. } And, since the Tick event handler is executed on GUI thread, the code which sets the actual time is straightforward.   1: private void OnDispatcherTimer(object sender, EventArgs e) 2: { 3: ShowTime(); 4: } We’re almost done. Let’s take a look how to stop the timers. It is easy with the Dispatcher Timer.   1: dispatcherTimer.Stop(); And slightly more complicated with the Timer. You should use Change method again.   1: timer.Change(Timeout.InfiniteTimeSpan, Timeout.InfiniteTimeSpan); What is the best way to add timer into an application? The Dispatcher Timer has simple interface, but its advantages are disadvantages at the same time. You should not use it if your Tick event handler executes time-consuming operations. It freezes your window which it is executing the event handler method. You should think about using System.Threading.Timer in this case. The code is available on GitHub.

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