Search Results

Search found 11594 results on 464 pages for 'pointer events'.

Page 25/464 | < Previous Page | 21 22 23 24 25 26 27 28 29 30 31 32  | Next Page >

  • [C++] Start a thread using a method pointer

    - by Michael
    Hi ! I'm trying to develop a thread abstraction (POSIX thread and thread from the Windows API), and I would very much like it to be able to start them with a method pointer, and not a function pointer. What I would like to do is an abstraction of thread being a class with a pure virtual method "runThread", which would be implanted in the future threaded class. I don't know yet about the Windows thread, but to start a POSIX thread, you need a function pointer, and not a method pointer. And I can't manage to find a way to associate a method with an instance so it could work as a function. I probably just can't find the keywords (and I've been searching a lot), I think it's pretty much what Boost::Bind() does, so it must exist. Can you help me ?

    Read the article

  • command&pointer&malloc [closed]

    - by gcc
    input 23 3 4 4 42 n 23 0 9 9 n n n 3 9 9 x //according to input,i should create int pointer arrays. pointer arrays starting from 1 (that is initial arrays is arrays[1].when program sees n ,it must be jumb to arrays 2 expected output arrays[1] 3 4 5 42 arrays[2] 23 0 9 9 arrays[5] 3 9 9 x is stopper n is comman to create new pointer array i am new in this site anyone help me how can i write

    Read the article

  • Initialize void pointer to point to an array

    - by idealistikz
    Suppose I have the following: typedef struct { int itemSize; int count; void *list; } Mystruct; Mystruct *InitStruct(int itemSize, int count) { Mystruct *my = malloc(sizeof(Mystruct)); my->itemSize = itemSize; my->count = count; //What is the best way to initialize list? For example: //my->list = malloc(count * sizeof(void *)); OR //my->list = malloc(count * sizeof(itemSize)); } //The following should return a pointer to the element stored at a given index void *Retrieve(const MyStruct *my, int index) { void *item; //What is the best way to return a pointer to the item at the given index from //my->list? } Mystruct is similar to an array and void *list is supposed to store the elements or pointers to the elements. Mystruct *InitStruct is a function that initializes a Mystruct pointer and void *Retrieve is a function that returns a pointer to the element stored at a given index. First, how should I initialize void* list? Should it hold the actual elements or be an array of pointers pointing to the elements? Second, using the void *Retrieve function, how do I return a pointer to the element stored at a given index in my-list?

    Read the article

  • When is "this" pointer initialized in C++?

    - by skydoor
    Hi I have a question about this pointer, when an object is constructed, when it is initialized? Which means, when can I use it? The virtual table is constructed in the constructor, is the same with this pointer? For example, I have a code like this. The output is 8. Does it mean that before the constructor is entered, this pointer is already initialized? class A{ public: A() { cout<<sizeof(*this);} int i; int *p; }; int main() { A a; } If it is true, what else would happen before the constructor is entered? If it is not true, when is the this pointer initialized?

    Read the article

  • jqGrid - customizing the multi-select option (restrict single selection and adding custom events)

    - by Renso
    Goal: Using the jgGrid to enable a selection of a checkbox for row selection - which is easy to set in the jqGrid - but also only allowing a single row to be selectable at a time while adding events based on whether the row was selected or de-selected. Environment: jQuery 1.4.4 jqGrid 3.4.4a Issue: The jqGrid does not support the option to restrict the multi-select to only allow for a single selection. You may ask, why bother with the multi-select checkbox function if you only want to allow for the selection of a single row? Good question, as an example, you want to reserve the selection of a row to trigger another kind of event and use the checkbox multi-select to handle a different kind of event; in other words, when I select the row I want something entirely different to happen than when I select to check off the checkbox for that row. Also the setSelection method of the jqGrid is a toggle and has no support for determining whether the checkbox has already been selected or not, So it will simply act as a switch - which it is designed to do - but with no way out of the box to only check off the box (as in not to de-select) rather than act like a switch. Furthermore, the getGridParam('selrow') does not indicate if the row was selected or de-selected, which seems a bit strange and is the main reason for this blog post. Solution: How this will act: When you check off a multi-select checkbox in the gird, and then commence to select another row by checking off that row's multi-select checkbox - I'm not talking there about clicking on the row but using the grid's multi-select checkbox - it will de-select the previous selection so that you are always left with only a single selection. Furthermore, once you select or de-select a multi-select checkbox, fire off an event that will be determined by whether or not the row was selected or de-selected, not just merely clicked on. So if I de-select the row do one thing but when selecting it do another. Implementation (this of course is only a partial code snippet):             multiselect: true,             multiboxonly: true,             onSelectRow: function (rowId) {                 var gridSelRow = $(item).getGridParam('selrow');                 var s;                 s = $(item).getGridParam('selarrrow');                 if (!s || !s[0]) {                     $(item).resetSelection();                     $('#productLineDetails').fadeOut();                     lastsel = null;                     return;                 }                 var selected = $.inArray(rowId, s) != -1;                 if (selected) {                     $('#productLineDetails').show();                 }                 else {                     $('#productLineDetails').fadeOut();                 }                 if (rowId && rowId !== lastsel && selected) {                     $(item).GridToForm(gridSelRow, '#productLineDetails');                     if (lastsel) $(item).setSelection(lastsel, false);                 }                 lastsel = rowId;             }, In the example code above: The "item" property is the id of the jqGrid. The following to settings ensure that the jqGrid will add the new column to select rows with a checkbox and also the not allow for the selection by clicking on the row but to force the user to have to click on the multi-select checkbox to select the row: multiselect: true, multiboxonly: true, Unfortunately the var gridSelRow = $(item).getGridParam('selrow') function will only return the row the user clicked on or rather that the row's checkbox was clicked on and NOT whether or not it was selected nor de-selected, but it retrieves the row id, which is what we will need. The following piece get's all rows that have been selected so far, as in have a checked off multi-select checkbox: var s; s = $(item).getGridParam('selarrrow'); Now determine if the checkbox the user just clicked on was selected or de-selected: var selected = $.inArray(rowId, s) != -1; If it was selected then show a container "#productLineDetails", if not hide that container away. The following instruction populates a form with the grid data using the built-in GridToForm method (just mentioned here as an example) ONLY if the row has been selected and NOT de-selected but more importantly to de-select any other multi-select checkbox that may have been selected: if (rowId && rowId !== lastsel && selected) {                     $(item).GridToForm(gridSelRow, '#productLineDetails');                     if (lastsel) $(item).setSelection(lastsel, false); }

    Read the article

  • Workstation 7 build 203739 - Capture Movie Mouse Pointer Not Visible

    - by BMIVM
    Hi, I have noticed that whenever I create a Capture Movie, the movie is fine but the mouse pointer is not visible at all. The clicks are on buttons file menus are executed but is hard for a viewer of the capturre movie session to follow the recording smoothly. This was not a problem in previous versions of WorkStation. Is this a bug or is there a setting I can set to see the mouse pointer? Note: VM Tools are installed, Host is Vista Ultimate Edtion SP1, x64 and the guest is a Win XP SP2. Thanks in advance for your help.

    Read the article

  • VMware Workstation 7 build 203739 - Capture Movie Mouse Pointer Not Visible

    - by BMIVM
    Hi, I have noticed that whenever I create a Capture Movie, the movie is fine but the mouse pointer is not visible at all. The clicks are on buttons file menus are executed but is hard for a viewer of the capturre movie session to follow the recording smoothly. This was not a problem in previous versions of WorkStation. Is this a bug or is there a setting I can set to see the mouse pointer? Note: VM Tools are installed, Host is Vista Ultimate Edtion SP1, x64 and the guest is a Win XP SP2. Thanks in advance for your help.

    Read the article

  • September Independent Oracle User Group (IOUG) Regional Events:

    - by Mandy Ho
    Normal 0 false false false EN-US X-NONE X-NONE MicrosoftInternetExplorer4 /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:10.0pt; font-family:"Calibri","sans-serif";} September 5, 2012 – Denver, CO Oracle 11g Database Upgrade Seminar Join Roy Swonger, Senior Director of software development at Oracle to learn about upgrading to Oracle Database 11g. Topics include: All the required preparatory steps Database upgrade strategies Post-upgrade performance analysis Helpful tips and common pitfalls to watch out for http://www.oracle.com/webapps/events/ns/EventsDetail.jsp?p_eventId=152242&src=7598177&src=7598177&Act=4 September 6, 2012 – Salt Lake City, UT Fall Symposium 2012 Plan to join us for our annual fall event on Sept 6. They day will be filled with learning and networking with tracks focused on Applications, APEX, BI, Development and DBA Topics. This event is free for UTOUG members to attend, but please register. http://www.utoug.org/apex/f?p=972:2:6686308836668467::::P2_EVENT_ID:121 September 6, 2012 – Portland, OR Oracle’s Hands on Workshop Series focused on providing Defense-in-Depth Solutions to secure data at the source, reduce risk and simplify compliance The Oracle Database Security Workshop is a one-day hands-on session for IT Managers, IT Security Architects and Oracle DBAs who are looking for solutions to address their information protection, privacy, and accountability challenges within their Oracle database environment. Most security programs offered today fail toadequately address database security. Customers continue to be challenged tosecure information against loss and protect the integrity of sensitiveinformation like critical financial data, personally identifiable information(PII) and credit card data for PCI compliance. http://nwoug.org/content.aspx?page_id=87&club_id=165905&item_id=241082 September 11, 2012 – Montreal, QC APEXposed! For APEX aficionados – join ODTUG in Montreal, September 11-12 for APEXposed! Topics will include Dynamic Actions, Plug-ins, Tuning, and Building Mobile Apps. The cost is $399 US and early registration ends August 15th. For more information: http://www.odtugapextraining.com  September 11, 2012 – Philadelphia, PA Big Data & What are we still doing wrong with Tom Kyte Tom Kyte is a Senior Technical Architect in Oracle's Server Technology Division. Tom is the Tom behind the AskTom column in Oracle Magazine and is also the author of Expert Oracle Database Architecture (Apress, 2005/2009) among other books Abstract: Big Data The term "big data" draws a lot of attention, but behind the hype there's a simple story. For decades, companies have been making business decisions based on transactional data stored in relational databases. However, beyond that critical data is a potential treasure trove of less structured data: weblogs, social media, email, sensors, and photographs that can be mined for useful information. This presentation will take a look at what Big Data is and means - and Oracle's strategy for handling it Abstract: What are we still doing wrong? I've given many best practices presentations in the last 10 years. I've given many worst practices presentations in the last 10 years. I've seen some things change over the last ten years and many other things stay exactly the same. In this talk - we'll be taking a look at the good and the bad - what we do right and what we continue to do wrong over and over again. We'll look at why "Why" is probably the right initial answer to most any question. We'll look at how we get to "Know what we Know", and why that can be both a help and a hindrance. We'll peek at "Best Practices" and tie them into what I term "Worst Practices". In short, a talk on the good and the bad. Normal 0 false false false EN-US X-NONE X-NONE MicrosoftInternetExplorer4 /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:10.0pt; font-family:"Calibri","sans-serif";} http://ioug.itconvergence.com/pls/apex/f?p=207:27:3669516430980563::NO September 12, 2012- New York, NY NYOUG Fall General Meeting “Trends in Database Administration and Why the Future of Database Administration is the Vdba” http://www.nyoug.org/upcoming_events.htm#General_Meeting1 September 21, 2012 – Cleveland, OH Oracle Database 11g for Developers: What You need to know or Oracle Database 11g New Features for Developers Attendees are introduced to the new and improved features of Oracle 11g (both Oracle 11g R1 and Oracle 11g R2) that directly impact application development. Special emphasis is placed on features that reduce development time, make development simpler, improve performance, or speed deployment. Specific topics include: New SQL functions, virtual columns, result caching, XML improvements, pivot statements, JDBC improvements, and PL/SQL enhancements such as compound triggers. http://www.neooug.org/ September 24, 2012 – Ottawa, ON Introduction to Oracle Spatial The free Oracle Locator functionality, and the Oracle Spatial option which dramatically extends Locator, are very useful, but poorly understood capabilities of the database. In the afternoon we will extend into additional areas selected from: storage and performance; answering business problems with spatial queries; using Oracle Maps in OBIEE; an overview and capabilities of Oracle Topology; under the covers with GeoCoding. Normal 0 false false false EN-US X-NONE X-NONE MicrosoftInternetExplorer4 /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:10.0pt; font-family:"Calibri","sans-serif";} http://www.oug-ottawa.org/pls/htmldb/f?p=327:27:4209274028390246::NO

    Read the article

  • How do I drag my widgets without dragging other widgets?

    - by Cypher
    I have a bunch of drag-able widgets on screen. When I am dragging one of the widgets around, if I drag the mouse over another widget, that widget then gets "snagged" and is also dragged around. While this is kind of a neat thing and I can think of a few game ideas based on that alone, that was not intended. :-P Background Info I have a Widget class that is the basis for my user interface controls. It has a bunch of properties that define it's size, position, image information, etc. It also defines some events, OnMouseOver, OnMouseOut, OnMouseClick, etc. All of the event handler functions are virtual, so that child objects can override them and make use of their implementation without duplicating code. Widgets are not aware of each other. They cannot tell each other, "Hey, I'm dragging so bugger off!" Source Code Here's where the widget gets updated (every frame): public virtual void Update( MouseComponent mouse, KeyboardComponent keyboard ) { // update position if the widget is being dragged if ( this.IsDragging ) { this.Left -= (int)( mouse.LastPosition.X - mouse.Position.X ); this.Top -= (int)( mouse.LastPosition.Y - mouse.Position.Y ); } ... // define and throw other events if ( !this.WasMouseOver && this.IsMouseOver && mouse.IsButtonDown( MouseButton.Left ) ) { this.IsMouseDown = true; this.MouseDown( mouse, new EventArgs() ); } ... // define and throw other events } And here's the OnMouseDown event where the IsDraggable property gets set: public virtual void OnMouseDown( object sender, EventArgs args ) { if ( this.IsDraggable ) { this.IsDragging = true; } } Problem Looking at the source code, it's obvious why this is happening. The OnMouseDown event gets fired whenever the mouse is hovered over the Widget and when the left mouse button is "down" (but not necessarily in that order!). That means that even if I hold the mouse down somewhere else on screen, and simply move it over anything that IsDraggable, it will "hook" onto the mouse and go for a ride. So, now that it's obvious that I'm Doing It Wrong™, how do I do this correctly?

    Read the article

  • Need Advice on designing ATL inproc Server (dll) that serves as both a soure and a sink of events.

    - by Andrew
    Hi, I need to design an ATL inproc server that besides exposing methods and properties, also can fire events (source) and serve as a sink for a third party COM control that fires events. I would assume that this is a fairly common requirement. I can also foresee several "gotchas" that I would like to read up on before commencing the design. My questions/concerns are: Can someone point me to an example? Which threading model to use? Should I have a seperate COM object for the sink? Should I, and how do I, protect certain memory. For example, my server will receive data from the third party control. It will save this, and in some cases, fire an event to interested clients. The interested clients will request the data through a standard method or property. I did try to research this myself. I can find many examples of COM servers that are soures, and some that are sinks, but never both. The only post I did find was this: http://www.generation-nt.com/us/atl-control-an-event-source-sink-help-9098542.html Which strongly advocates putting the sink on a seperate COM object. Any leads, tutorials or ideas would be much appreciated. Thanks, Andrew

    Read the article

  • How to intercept touch events globally?

    - by mystify
    I have an view which is sometimes covered by some other views. However, if the user slides the finger across the screen, I want to slide that underlying view across the screen, too. I could start making custom views for all those covering subviews and forward all kinds of touch events, but that's somewhat cumbersome. Maybe there's some kind of notification or another way that a UIView or UIControl subclass can be aware of touch events happening right now, no matter where they are. In short: I need an UIView subclass or UIControl subclass which knows about any touch events happening on the entire screen. Or at least if tht's not possible, knowing about any touch events happening above itself in the same underlying superview. Another description: There are 20 views, all reside inside the same superview. The first view is covered by 19 others. But if the user slides across the screen, that first view must slide too, so it must be aware of touch events. Is there any better solution that making all 19 views forward touch events? (yes, all 19 views respond to touch events in this example)

    Read the article

  • Need alternative to Accessibility's "Locate Pointer" to visually highlight the mouse.

    - by fred.bear
    Update: See end of quetion: A black-on-white cross-hair/I-bar mouse-pointer is soemtimes hard foe me to spot in amongst black-on-white text. I've tried "Accessibility / Mouse Accessibility / Locate Pointer" .. which will: Show pointer position when Control is presssed It works (to a point), but it does have a notable problem, which renders it inpractical. It has the uncanny side-effect of disallowing all Control key navigation while editing a file/dir name in Nautilus (F2).. Just touching the Control key drops it out of edit mode, which means I can't keyboard paste, move-L/R word etc... So, I'm looking for an alternative. I've tried Compiz's Water Effect, but I need something which is sharper, faster, and localized to the pointer. Compiz's Show Mouse (with fire) is no suitable. I'm really lookingf for an analog of "Accessibility / Locate Pointer": * ie. I hit Control (only).. and it blips a quick visual pulse. UPDATE: I've just realized why I can't find my mouse so often! ... It's because it is isn't there !!! ... Two apps I use a lot, Gedit and Konsole (KDE Terminal; it renders unicode better), ... dissolve the mouse-pointer to invisible after the first key is typed ... and Konsole does it after a few seconds of idle-time... like a video-player option: "hide the mouse".. Well I don't use the mouse much, and I thought it was juse my eyesight (which does rely a lot on Compiz's zoom)... I discovered it when I installed a "novelty" app, called Geyes from gnome-applets ("A goofy set of eyes for the GNOME panel. They follow your mouse.") ... It could follow the mouse better than me! :)

    Read the article

  • Tech Article: Tired of Null Pointer Exceptions? Use Java SE 8's Optional!

    - by Tori Wieldt
    A wise man once said you are not a real Java programmer until you've dealt with a null pointer exception. The null reference is the source of many problems because it is often used to denote the absence of a value. Java SE 8 introduces a new class called java.util.Optional that can alleviate some of these problems. In the tech article "Tired of Null Pointer Exceptions? Use Java SE 8's Optional!" Java expert Raoul-Gabriel Urma shows you how to make your code more readable and protect it against null pointer exceptions. Urma explains "The purpose of Optional is not to replace every single null reference in your codebase but rather to help design better APIs in which—just by reading the signature of a method—users can tell whether to expect an optional value. In addition, Optional forces you to actively unwrap an Optional to deal with the absence of a value; as a result, you protect your code against unintended null pointer exceptions." Learn how to go from writing painful nested null checks to writing declarative code that is composable, readable, and better protected from null pointer exceptions. Read "Tired of Null Pointer Exceptions? Use Java SE 8's Optional!"

    Read the article

  • Can Windows logoff events be tracked?

    - by Massimo
    I'm working on an application to track network user logon/logoff events in an Active Directory domain; the application will work by auditing security logs on domain controllers. Auditing logon events can get somewhat tricky, but it can succesfully be done. My problem: how can I track logoff events? Based on some research I've done, it looks like these events are only logged locally on workstations, but not on DCs; also, the "lastLogoff" attribute exists on AD user objects, but it's not actually used by anyone. This is a very specific question: is something logged on DCs when a user logs off from a domain workstation? To clarify: I'm not intereseted in other auditing mehods, I can't deploy logon/logoff scripts and I can't install anything anywhere; I also know opened and closed network sessions are logged, but this is not what I'm looking for. I need to audit interactive logons and logoffs to domain workstations, and I can do this by only reading domain controllers security logs; reading each workstation's local event logs is out of question. If this can't be done, it's ok; but I need a clear answer on that. Can this be done? If yes, how?

    Read the article

  • mouse pointer moving on its own

    - by PA
    After two months of working correctly, I am experiencing an strange and very annoying problem. My mouse pointer is moving on its own. If I move the mouse to the left, as soon as I stop the movement, the pointer runs again to the far right. This makes the mouse totally unusable. The mouse device is an optical USB mouse. It is not a problem with the mouse itself. I have tried with another mouse, same problem. (both mice are OK, I have tried both mice on my laptop, both worked perfectly) Have tried different surfaces, too. Same problem. System is Windows XP Pro SP3. Computer is a desktop PC two months old. I suspected it could be a problem with the mouse driver. But both mice are from different brand, so I suppose they use different drivers. What else can I try? any suggestion?

    Read the article

  • How can I process a form's events in another class in VB.NET?

    - by CowKingDeluxe
    Here's my code: Public Class Form1 End Class Public Class Form1Handler Inherits Form1 Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click MsgBox("I") End Sub End Class I'm trying to get Form1Handler to process Form1's events automatically. How can I do this? Should I use a module instead? I'm doing this in VB 2010.

    Read the article

  • What is the difference between the Control.Enter and Control.GotFocus events?

    - by jameswelle
    This may be a basic question, but I have to admit I've never truly understood what the difference between the Control.Enter and Control.GotFocus events is. http://msdn.microsoft.com/en-us/library/system.windows.forms.control.enter.aspx http://msdn.microsoft.com/en-us/library/system.windows.forms.control.gotfocus.aspx Is it a differentiation between capturing keyboard or mouse input or something else?

    Read the article

  • How do I avoid multiple key up/down/press events when holding a key?

    - by Rammay
    I'm creating a web front end to control a small robot. Ajax calls will be made on a keydown, to start the robot, and keyup to stop it. My problem is that when a key is held down the keyup, keydown, and keypress events seem to cycle continually. Does anybody know of a way to only have keydown fire when the key is first pressed and keyup to fire when it has been released?

    Read the article

  • Which conventions, events, etc. should I look into attending?

    - by perlox
    I am a student programmer and relatively new to the industry. Once I get out into the real world and have money to blow, which events/conventions/conferences/etc. should I look into attending? Which do you consider a must-attend-at-least-once-in-your-life-as-a-developer type of event? Just to clarify, any language, company, size, are acceptable. I'm mostly looking to generate a list of highly regarded conferences for a variety of different fields/interests.

    Read the article

  • wxWidgets/wxPython: Do two identical events cause two handlings?

    - by cool-RR
    When there are two identical events in the event loop, will wxPython handle both of them, or will it call the handler only once for them both? I mean, in my widget I want to have an event like EVT_NEED_TO_RECALCULATE_X. I want this event to be posted in all kinds of different circumstances that require x to be recalculated. However, even if there are two different reasons to recalculate x, only one recalculation needs to be done. How do I do this?

    Read the article

  • UITouch Event Propagation To Background UIViews

    - by drewww
    I'm having troubles getting any UIView that's not the foreground UIView to receive UITouch events. I'm building an all-Core Graphics-app, so I'm not using any built in UIViews or IB or anything - everything is programmatically constructed and drawn into. Here's my view hierarchy: Root View Type A Container Type A View Type A View Type A View Type B Container Type B View Type B View Type B View The containers are just vanilla UIView objects that I create programmatically and add instances of Type A and B to when they're created. I did this originally to make hitTesting easier—Type A objects can be drag-and-dropped onto Type B objects. Type A objects receive touch events fine, but Type B objects (which are contained by Type B Container which is behind Type A Container) don't receive touch events. Both containers occupy the entire screen; they're basically just convenience containers. If I pull Type B Container to the front (eg [self.view bringSubviewToFront:Type B Container]) it receives events properly, but then the Type A Container doesn't get events. How do I propagate events from the view that's on top? Both views occupy the entire screen, so it makes sense that the top-most view is catching the events, but how should I get it to pass those events on to Type B Container? I could inject some code in the container that passes the touch events back to the main ViewController which can pass them on to Type B Container but that feels really messy to me. Is there a nicer way to not have the Type A Container stop propagation? What's the best practice here?

    Read the article

  • Issuing Current Time Increments in StreamInsight (A Practical Example)

    The issuing of a Current Time Increment, Cti, in StreamInsight is very definitely one of the most important concepts to learn if you want your Streams to be responsive. A full discussion of how to issue Ctis is beyond the scope of this article but a very good explanation in addition to Books Online can be found in these three articles by a member of the StreamInsight team at Microsoft, Ciprian Gerea. Time in StreamInsight Series http://blogs.msdn.com/b/streaminsight/archive/2010/07/23/time-in-streaminsight-i.aspx http://blogs.msdn.com/b/streaminsight/archive/2010/07/30/time-in-streaminsight-ii.aspx http://blogs.msdn.com/b/streaminsight/archive/2010/08/03/time-in-streaminsight-iii.aspx A lot of the problems I see with unresponsive or stuck streams on the MSDN Forums are to do with how Ctis are enqueued or in a lot of cases not enqueued. If you enqueue events and never enqueue a Cti then StreamInsight will be perfectly happy. You, on the other hand, will never see data on the output as you have not told StreamInsight to flush the stream. This article deals with a specific implementation problem I had recently whilst working on a StreamInsight project. I look at some possible options and discuss why they would not work before showing the way I solved the problem. The stream of data I was dealing with on this project was very bursty that is to say when events were flowing they came through very quickly and in large numbers (1000 events/sec), but when the stream calmed down it could be a few seconds between each event. When enqueuing events into the StreamInsight engne it is best practice to do so with a StartTime that is given to you by the system producing the event . StreamInsight processes events and it doesn't matter whether those events are being pushed into the engine by a source system or the events are being read from something like a flat file in a directory somewhere. You can apply the same logic and temporal algebra to both situations. Reading from a file is an excellent example of where the time of the event on the source itself is very important. We could be reading that file a long time after it was written. Being able to read the StartTime from the events allows us to define windows that will hold the correct sets of events. I was able to do this with my stream but this is where my problems started. Below is a very simple script to create a SQL Server table and populate it with sample data that will show exactly the problem I had. CREATE TABLE [dbo].[t] ( [c1] [int] PRIMARY KEY, [c2] [datetime] NULL ) INSERT t VALUES (1,'20100810'),(2,'20100810'),(3,'20100810') Column c2 defines the StartTime of the event on the source and as you can see the values in all 3 rows of data is the same. If we read Ciprian’s articles we know that we can define how Ctis get injected into the stream in 3 different places The Stream Definition The Input Factory The Input Adapter I personally have always been a fan of enqueing Ctis through the factory. Below is code typical of what I would use to do this On the class itself I do some inheriting public class SimpleInputFactory : ITypedInputAdapterFactory<SimpleInputConfig>, ITypedDeclareAdvanceTimeProperties<SimpleInputConfig> And then I implement the following function public AdapterAdvanceTimeSettings DeclareAdvanceTimeProperties<TPayload>(SimpleInputConfig configInfo, EventShape eventShape) { return new AdapterAdvanceTimeSettings( new AdvanceTimeGenerationSettings(configInfo.CtiFrequency, TimeSpan.FromTicks(-1)), AdvanceTimePolicy.Adjust); } The configInfo .CtiFrequency property is a value I pass through to define after how many events I want a Cti to be injected and this in turn will flush through the stream of data. I usually pass a value of 1 for this setting. The second parameter determines the CTI timestamp in terms of a delay relative to the events. -1 ticks in the past results in 1 tick in the future, i.e., ahead of the event. The problem with this method though is that if consecutive events have the same StartTime then only one of those events will be enqueued. In this example I use the following to define how I assign the StartTime of my events currEvent.StartTime = (DateTimeOffset)dt.c2; If I go ahead and run my StreamInsight process with this configuration i can see on the output adapter that two events have been removed To see this in a little more depth I can use the StreamInsight Debugger and see what happens internally. What is happening here is that the first event arrives and a Cti is injected with a time of 1 tick after the StartTime of that event (Also the EndTime of the event). The second event arrives and it has a StartTime of before the Cti and even though we specified AdvanceTimePolicy.Adjust on the factory we know that a point event can never be adjusted like this and the event is dropped. The same happens for the third event as well (The second and third events get trumped by the Cti). For a more detailed discussion of why this happens look here http://www.sqlis.com/sqlis/post/AdvanceTimePolicy-and-Point-Event-Streams-In-StreamInsight.aspx We end up with a single event being pushed into the output adapter and our result now makes sense. The next way I tried to solve this problem by changing the value of the second parameter to TimeSpan.Zero Here is how my factory code now looks public AdapterAdvanceTimeSettings DeclareAdvanceTimeProperties<TPayload>(SimpleInputConfig configInfo, EventShape eventShape) { return new AdapterAdvanceTimeSettings( new AdvanceTimeGenerationSettings(configInfo.CtiFrequency, TimeSpan.Zero), AdvanceTimePolicy.Adjust); } What I am doing here is declaring a policy that says inject a Cti together with every event and stamp it with a StartTime that is equal to the start time of the event itself (TimeSpan.Zero). This method has plus points as well as a downside. The upside is that no events will be lost by having the same StartTime as previous events. The Downside is that because the Cti is declared with the StartTime of the event itself then it does not actually flush that particular event because in the StreamInsight algebra, a Cti commits only those events that occurred strictly before them. To flush the events we need a Cti to be enqueued with a greater StartTime than the events themselves. Here is what happened when I ran this configuration As you can see all we got through was the Cti and none of the events. The debugger output shows the stamps on the Cti and the events themselves. Because the Cti issued has the same timestamp (StartTime) as the events then none of the events get flushed. I was nearly there but not quite. Because my stream was bursty it was possible that the next event would not come along for a few seconds and this was far too long for an event to be enqueued and not be flushed to the output adapter. I needed another solution. Two possible solutions crossed my mind although only one of them made sense when I explored it some more. Where multiple events have the same StartTime I could add 1 tick to the first event, two to the second, three to third etc thereby giving them unique StartTime values. Add a timer to manually inject Ctis The problem with the first implementation is that I would be giving the events a new StartTime. This would cause me the following problems If I want to define windows over the stream then some events may not be captured in the right windows and therefore any calculations on those windows I did would be wrong What would happen if we had 10,000 events with the same StartTime? I would enqueue them with StartTime + n ticks. Along comes a genuine event with a StartTime of the very first event + 1 tick. It is now too far in the past as far as my stream is concerned and it would be dropped. Not what I would want to do at all. I decided then to look at the Timer based solution I created a timer on my input adapter that elapsed every 200ms. private Timer tmr; public SimpleInputAdapter(SimpleInputConfig configInfo) { ctx = new SimpleTimeExtractDataContext(configInfo.ConnectionString); this.configInfo = configInfo; tmr = new Timer(200); tmr.Elapsed += new ElapsedEventHandler(t_Elapsed); tmr.Enabled = true; } void t_Elapsed(object sender, ElapsedEventArgs e) { ts = DateTime.Now - dtCtiIssued; if (ts.TotalMilliseconds >= 200 && TimerIssuedCti == false) { EnqueueCtiEvent(System.DateTime.Now.AddTicks(-100)); TimerIssuedCti = true; } }   In the t_Elapsed event handler I find out the difference in time between now and when the last event was processed (dtCtiIssued). I then check to see if that is greater than or equal to 200ms and if the last issuing of a Cti was done by the timer or by a genuine event (TimerIssuedCti). If I didn’t do this check then I would enqueue a Cti every time the timer elapsed which is not something I wanted. If the difference between the two times is greater than or equal to 500ms and the last event enqueued was by a real event then I issue a Cti through the timer to flush the event Queue, otherwise I do nothing. When I enqueue the Ctis into my stream in my ProduceEvents method I also set the values of dtCtiIssued and TimerIssuedCti   currEvent = CreateInsertEvent(); currEvent.StartTime = (DateTimeOffset)dt.c2; TimerIssuedCti = false; dtCtiIssued = currEvent.StartTime; If I go ahead and run this configuration I see the following in my output. As we can see the first Cti gets enqueued as before but then another is enqueued by the timer and because this has a later timestamp it flushes the enqueued events through the engine. Conclusion Hopefully this has shown how the enqueuing of Ctis can have a dramatic effect on the responsiveness of your output in StreamInsight. Understanding the temporal nature of the product is for me one of the most important things you can learn. I have attached my solution for the demos. It is all in one project and testing each variation is a simple matter of commenting and un-commenting the parts in the code we have been dealing with here.

    Read the article

  • SQL SERVER – SSMS: Backup and Restore Events Report

    - by Pinal Dave
    A DBA wears multiple hats and in fact does more than what an eye can see. One of the core task of a DBA is to take backups. This looks so trivial that most developers shrug this off as the only activity a DBA might be doing. I have huge respect for DBA’s all around the world because even if they seem cool with all the scripting, automation, maintenance works round the clock to keep the business working almost 365 days 24×7, their worth is knowing that one day when the systems / HDD crashes and you have an important delivery to make. So these backup tasks / maintenance jobs that have been done come handy and are no more trivial as they might seem to be as considered by many. So the important question like: “When was the last backup taken?”, “How much time did the last backup take?”, “What type of backup was taken last?” etc are tricky questions and this report lands answers to the same in a jiffy. So the SSMS report, we are talking can be used to find backups and restore operation done for the selected database. Whenever we perform any backup or restore operation, the information is stored in the msdb database. This report can utilize that information and provide information about the size, time taken and also the file location for those operations. Here is how this report can be launched.   Once we launch this report, we can see 4 major sections shown as listed below. Average Time Taken For Backup Operations Successful Backup Operations Backup Operation Errors Successful Restore Operations Let us look at each section next. Average Time Taken For Backup Operations Information shown in “Average Time Taken For Backup Operations” section is taken from a backupset table in the msdb database. Here is the query and the expanded version of that particular section USE msdb; SELECT (ROW_NUMBER() OVER (ORDER BY t1.TYPE))%2 AS l1 ,       1 AS l2 ,       1 AS l3 ,       t1.TYPE AS [type] ,       (AVG(DATEDIFF(ss,backup_start_date, backup_finish_date)))/60.0 AS AverageBackupDuration FROM backupset t1 INNER JOIN sys.databases t3 ON ( t1.database_name = t3.name) WHERE t3.name = N'AdventureWorks2014' GROUP BY t1.TYPE ORDER BY t1.TYPE On my small database the time taken for differential backup was less than a minute, hence the value of zero is displayed. This is an important piece of backup operation which might help you in planning maintenance windows. Successful Backup Operations Here is the expanded version of this section.   This information is derived from various backup tracking tables from msdb database.  Here is the simplified version of the query which can be used separately as well. SELECT * FROM sys.databases t1 INNER JOIN backupset t3 ON (t3.database_name = t1.name) LEFT OUTER JOIN backupmediaset t5 ON ( t3.media_set_id = t5.media_set_id) LEFT OUTER JOIN backupmediafamily t6 ON ( t6.media_set_id = t5.media_set_id) WHERE (t1.name = N'AdventureWorks2014') ORDER BY backup_start_date DESC,t3.backup_set_id,t6.physical_device_name; The report does some calculations to show the data in a more readable format. For example, the backup size is shown in KB, MB or GB. I have expanded first row by clicking on (+) on “Device type” column. That has shown me the path of the physical backup file. Personally looking at this section, the Backup Size, Device Type and Backup Name are critical and are worth a note. As mentioned in the previous section, this section also has the Duration embedded inside it. Backup Operation Errors This section of the report gets data from default trace. You might wonder how. One of the event which is tracked by default trace is “ErrorLog”. This means that whatever message is written to errorlog gets written to default trace file as well. Interestingly, whenever there is a backup failure, an error message is written to ERRORLOG and hence default trace. This section takes advantage of that and shows the information. We can read below message under this section, which confirms above logic. No backup operations errors occurred for (AdventureWorks2014) database in the recent past or default trace is not enabled. Successful Restore Operations This section may not be very useful in production server (do you perform a restore of database?) but might be useful in the development and log shipping secondary environment, where we might be interested to see restore operations for a particular database. Here is the expanded version of the section. To fill this section of the report, I have restored the same backups which were taken to populate earlier sections. Here is the simplified version of the query used to populate this output. USE msdb; SELECT * FROM restorehistory t1 LEFT OUTER JOIN restorefile t2 ON ( t1.restore_history_id = t2.restore_history_id) LEFT OUTER JOIN backupset t3 ON ( t1.backup_set_id = t3.backup_set_id) WHERE t1.destination_database_name = N'AdventureWorks2014' ORDER BY restore_date DESC,  t1.restore_history_id,t2.destination_phys_name Have you ever looked at the backup strategy of your key databases? Are they in sync and do we have scope for improvements? Then this is the report to analyze after a week or month of maintenance plans running in your database. Do chime in with what are the strategies you are using in your environments. Reference: Pinal Dave (http://blog.sqlauthority.com)Filed under: PostADay, SQL, SQL Authority, SQL Backup and Restore, SQL Query, SQL Server, SQL Server Management Studio, SQL Tips and Tricks, T SQL Tagged: SQL Reports

    Read the article

< Previous Page | 21 22 23 24 25 26 27 28 29 30 31 32  | Next Page >