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  • How to fix "The connection was restarted"?

    - by Altar
    I have a php script with ajax. Few days ago, without making any changes, the script stopped working. The script is working sometimes but it is very slow. Other times it doesn't load completely. Yet other times it loads and empty page or it shows a "The connection was restarted" message. We have tried loading the page from 4 different computers in two different countries (two different ISPs). There is nothing relevant in the server's log. We contacted iPage.com hosting support. We sent screenshots. And all we manage to get from them was an incomplete screenshot and the message 'We tested. The page loads'. So, they won't admit the fault. It looks like they loaded the page once and declared it is working and went back to playing solitaire. I know their support. We had all kind of problems with iPage hosting. My questions are: 1. There is any way to make this error more easy to reproduce? I mean instead of fixing the error to get it appear more often. 2. There is any way to test a server response, to see if it drops connections?

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  • Win7 taskbar freezes on startup for about 1-2 mins

    - by Mike
    Running Win7 64-bit for about 4 months now. Never had this problem, didn't install anything new recently. When I boot up I can't do anything in the taskbar, it's frozen for about 1-2 minutes then everything is normal. I can right click on my desktop and move my mouse around. This randomly just started happening a couple days ago after a reboot. I have a 3.2ghz quad, SSD, 4 gig ram, etc. and it usually starts up quickly. After some troubleshooting (including running antivirus and Anti-Malware), it doesn't appear to be software related, but appears to be services related. I can boot up in safe mode and safe mode with networking just fine. I can also boot up normally with all my regular software loading at startup, BUT with all my services turned off. Now the odd part. When I run msconfig to disable all the services at startup and go through ticking them on 5-10 at a time or so and booting up it seems to be somewhat random. Ticking everything on from "Application Experience" halfway down to about "Quality Windows Audio Video Experience" and I can boot without the 1-2 min. freeze. Then I start ticking the stuff below that from a couple of Remote Accesses to Smart Card and Task Scheduler, etc. But the weird part is sometimes it will freeze sometimes it won't. I can't narrow it down. Then if it freezes, I'll boot up in safe mode and turn the ones I just turned on back off and I'll reboot normally but it will freeze again. Which makes no sense because that configuration just worked without freezing just before. I got frustrated enough that I backed up and wiped my hard drive (formatted and everything) and reinstalled Win7 but when I booted up, the freeze happened again. Any ideas? Thanks in advance.

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  • Browser: Randomly Opens Pages in New Windows Without Reason?

    - by Mark R
    This is a very strange thing I've noticed on my computer and past computers over this past year or more. I know when page are meant to open in a new Window and know which settings to use on my browser for this. But on both my browsers Chrome and Firefox, I have this really strange issue. I'm starting to think it's a hacker. When I right click links and select Open Link in New Tab, sometimes they will randomly open in a new window and today it is happening a lot. Like lots and lots. I'm getting really creeped out by it and YES I understand when a link opens in a new window and when it isn't supposed to. And none of these links are meant to open in a new Window. Let me give you an example: I searched Google about my issue and clicked on the result that I thought good. It opened in a new tab but half way through loading in new tab it opens into a new window. Recently, I decided to record my screen and while recording my screen using Camtasia, the issue stops. When I stop recording it starts again, as if it's a human operated issue. VERY strange. This has been going on for months on my old and new computer and on both Firefox and Chrome. Is there something I can do to fix this intermittent problem?

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  • Some pages begin to load and stop on Chrome

    - by corsiKa
    I'm using Chrome (Version 22.0.1229.94). About 20% of pages simply stop loading after a second or two. Sometimes, I'm able to click an early link after a second or third reload. If I attempt to close the page, it continues to hang for a few (10-30) additional seconds, then closes. However, if I switch to other tabs, it works just fine. If I don't change tabs and wait long enough, it says that there's something on the page that's taking too long to run and offers to let me kill it. Only a select number of sites fail to load, and they do so consistently. None of the stackexchange sites or google fail, but others like realclearpolitics and wowwiki do. I visit those sites every day, and this is the first time it has failed like this. If it were just one site, I would say someone messed something up in their deployment. But it seems incredibly peculiar that suddenly, half a dozen popular sites all mysteriously have the same symptoms. If I attempt to load the pages in Firefox or IE9, they load just fine. Nothing new has been installed, regarding Chrome or otherwise. Antivirus reports no abnormalities. System is regularly patched. Restarting both chrome and the computer have had no effect.

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  • Windows 7 constantly accessing hard drive [duplicate]

    - by Zohar
    Possible Duplicate: Tool which finds which process is causing the heavy hard drive activity? Did you notice that on Windows 7 (I use 64-bit) the hard drive LED is constantly blinking, which means that the OS is constantly wearing the hard drive by accessing it? It's something related to the system process, and it even occurs in safe mode, so I don't think it's a third party software problem. Has anyone experienced this problem as well, and is it a Windows problem, or caused by something else? Edit: My indexing service is reduced to indexing only the Start Menu. Even if it was set for the whole computer, it would eventually stop; that's not it. My friends also suffer from the same problem. Please answer my first question: have any of you have seen a Windows 7 machine whose hard drive LED is at rest? I'm also trying to track down the offending process using procmon and Resource Monitor, and it actually seems like a system process. It could also be svchost.exe, and I'm not sure which file they are accessing since I see a lot of activity which I can't make sense of. It's loading system DLLs, accessing registry keys, and other nonsense.

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  • how to use 3D map Actionscript class in mxml file for display map.

    - by nemade-vipin
    hello friends, I have created the application in which I have to use 3D map Action Script class in mxml file to display a map in form. that is in tab navigator last tab. My ActionScript 3D map class is(FlyingDirections):- package src.SBTSCoreObject { import src.SBTSCoreObject.JSONDecoder; import com.google.maps.InfoWindowOptions; import com.google.maps.LatLng; import com.google.maps.LatLngBounds; import com.google.maps.Map3D; import com.google.maps.MapEvent; import com.google.maps.MapOptions; import com.google.maps.MapType; import com.google.maps.MapUtil; import com.google.maps.View; import com.google.maps.controls.NavigationControl; import com.google.maps.geom.Attitude; import com.google.maps.interfaces.IPolyline; import com.google.maps.overlays.Marker; import com.google.maps.overlays.MarkerOptions; import com.google.maps.services.Directions; import com.google.maps.services.DirectionsEvent; import com.google.maps.services.Route; import flash.display.Bitmap; import flash.display.DisplayObject; import flash.display.DisplayObjectContainer; import flash.display.Loader; import flash.display.LoaderInfo; import flash.display.Sprite; import flash.events.Event; import flash.events.IOErrorEvent; import flash.events.MouseEvent; import flash.events.TimerEvent; import flash.filters.DropShadowFilter; import flash.geom.Point; import flash.net.URLLoader; import flash.net.URLRequest; import flash.net.navigateToURL; import flash.text.TextField; import flash.text.TextFieldAutoSize; import flash.text.TextFormat; import flash.utils.Timer; import flash.utils.getTimer; public class FlyingDirections extends Map3D { /** * Panoramio home page. */ private static const PANORAMIO_HOME:String = "http://www.panoramio.com/"; /** * The icon for the car. */ [Embed("assets/car-icon-24px.png")] private static const Car:Class; /** * The Panoramio icon. */ [Embed("assets/iw_panoramio.png")] private static const PanoramioIcon:Class; /** * We animate a zoom in to the start the route before the car starts * to move. This constant sets the time in seconds over which this * zoom occurs. */ private static const LEAD_IN_DURATION:Number = 3; /** * Duration of the trip in seconds. */ private static const TRIP_DURATION:Number = 40; /** * Constants that define the geometry of the Panoramio image markers. */ private static const BORDER_T:Number = 3; private static const BORDER_L:Number = 10; private static const BORDER_R:Number = 10; private static const BORDER_B:Number = 3; private static const GAP_T:Number = 2; private static const GAP_B:Number = 1; private static const IMAGE_SCALE:Number = 1; /** * Trajectory that the camera follows over time. Each element is an object * containing properties used to generate parameter values for flyTo(..). * fraction = 0 corresponds to the start of the trip; fraction = 1 * correspondsto the end of the trip. */ private var FLY_TRAJECTORY:Array = [ { fraction: 0, zoom: 6, attitude: new Attitude(0, 0, 0) }, { fraction: 0.2, zoom: 8.5, attitude: new Attitude(30, 30, 0) }, { fraction: 0.5, zoom: 9, attitude: new Attitude(30, 40, 0) }, { fraction: 1, zoom: 8, attitude: new Attitude(50, 50, 0) }, { fraction: 1.1, zoom: 8, attitude: new Attitude(130, 50, 0) }, { fraction: 1.2, zoom: 8, attitude: new Attitude(220, 50, 0) }, ]; /** * Number of panaramio photos for which we load data. We&apos;ll select a * subset of these approximately evenly spaced along the route. */ private static const NUM_GEOTAGGED_PHOTOS:int = 50; /** * Number of panaramio photos that we actually show. */ private static const NUM_SHOWN_PHOTOS:int = 7; /** * Scaling between real trip time and animation time. */ private static const SCALE_TIME:Number = 0.001; /** * getTimer() value at the instant that we start the trip. If this is 0 then * we have not yet started the car moving. */ private var startTimer:int = 0; /** * The current route. */ private var route:Route; /** * The polyline for the route. */ private var polyline:IPolyline; /** * The car marker. */ private var marker:Marker; /** * The cumulative duration in seconds over each step in the route. * cumulativeStepDuration[0] is 0; cumulativeStepDuration[1] adds the * duration of step 0; cumulativeStepDuration[2] adds the duration * of step 1; etc. */ private var cumulativeStepDuration:/*Number*/Array = []; /** * The cumulative distance in metres over each vertex in the route polyline. * cumulativeVertexDistance[0] is 0; cumulativeVertexDistance[1] adds the * distance to vertex 1; cumulativeVertexDistance[2] adds the distance to * vertex 2; etc. */ private var cumulativeVertexDistance:Array; /** * Array of photos loaded from Panoramio. This array has the same format as * the &apos;photos&apos; property within the JSON returned by the Panoramio API * (see http://www.panoramio.com/api/), with additional properties added to * individual photo elements to hold the loader structures that fetch * the actual images. */ private var photos:Array = []; /** * Array of polyline vertices, where each element is in world coordinates. * Several computations can be faster if we can use world coordinates * instead of LatLng coordinates. */ private var worldPoly:/*Point*/Array; /** * Whether the start button has been pressed. */ private var startButtonPressed:Boolean = false; /** * Saved event from onDirectionsSuccess call. */ private var directionsSuccessEvent:DirectionsEvent = null; /** * Start button. */ private var startButton:Sprite; /** * Alpha value used for the Panoramio image markers. */ private var markerAlpha:Number = 0; /** * Index of the current driving direction step. Used to update the * info window content each time we progress to a new step. */ private var currentStepIndex:int = -1; /** * The fly directions map constructor. * * @constructor */ public function FlyingDirections() { key="ABQIAAAA7QUChpcnvnmXxsjC7s1fCxQGj0PqsCtxKvarsoS-iqLdqZSKfxTd7Xf-2rEc_PC9o8IsJde80Wnj4g"; super(); addEventListener(MapEvent.MAP_PREINITIALIZE, onMapPreinitialize); addEventListener(MapEvent.MAP_READY, onMapReady); } /** * Handles map preintialize. Initializes the map center and zoom level. * * @param event The map event. */ private function onMapPreinitialize(event:MapEvent):void { setInitOptions(new MapOptions({ center: new LatLng(-26.1, 135.1), zoom: 4, viewMode: View.VIEWMODE_PERSPECTIVE, mapType:MapType.PHYSICAL_MAP_TYPE })); } /** * Handles map ready and looks up directions. * * @param event The map event. */ private function onMapReady(event:MapEvent):void { enableScrollWheelZoom(); enableContinuousZoom(); addControl(new NavigationControl()); // The driving animation will be updated on every frame. addEventListener(Event.ENTER_FRAME, enterFrame); addStartButton(); // We start the directions loading now, so that we&apos;re ready to go when // the user hits the start button. var directions:Directions = new Directions(); directions.addEventListener( DirectionsEvent.DIRECTIONS_SUCCESS, onDirectionsSuccess); directions.addEventListener( DirectionsEvent.DIRECTIONS_FAILURE, onDirectionsFailure); directions.load("48 Pirrama Rd, Pyrmont, NSW to Byron Bay, NSW"); } /** * Adds a big blue start button. */ private function addStartButton():void { startButton = new Sprite(); startButton.buttonMode = true; startButton.addEventListener(MouseEvent.CLICK, onStartClick); startButton.graphics.beginFill(0x1871ce); startButton.graphics.drawRoundRect(0, 0, 150, 100, 10, 10); startButton.graphics.endFill(); var startField:TextField = new TextField(); startField.autoSize = TextFieldAutoSize.LEFT; startField.defaultTextFormat = new TextFormat("_sans", 20, 0xffffff, true); startField.text = "Start!"; startButton.addChild(startField); startField.x = 0.5 * (startButton.width - startField.width); startField.y = 0.5 * (startButton.height - startField.height); startButton.filters = [ new DropShadowFilter() ]; var container:DisplayObjectContainer = getDisplayObject() as DisplayObjectContainer; container.addChild(startButton); startButton.x = 0.5 * (container.width - startButton.width); startButton.y = 0.5 * (container.height - startButton.height); var panoField:TextField = new TextField(); panoField.autoSize = TextFieldAutoSize.LEFT; panoField.defaultTextFormat = new TextFormat("_sans", 11, 0x000000, true); panoField.text = "Photos provided by Panoramio are under the copyright of their owners."; container.addChild(panoField); panoField.x = container.width - panoField.width - 5; panoField.y = 5; } /** * Handles directions success. Starts flying the route if everything * is ready. * * @param event The directions event. */ private function onDirectionsSuccess(event:DirectionsEvent):void { directionsSuccessEvent = event; flyRouteIfReady(); } /** * Handles click on the start button. Starts flying the route if everything * is ready. */ private function onStartClick(event:MouseEvent):void { startButton.removeEventListener(MouseEvent.CLICK, onStartClick); var container:DisplayObjectContainer = getDisplayObject() as DisplayObjectContainer; container.removeChild(startButton); startButtonPressed = true; flyRouteIfReady(); } /** * If we have loaded the directions and the start button has been pressed * start flying the directions route. */ private function flyRouteIfReady():void { if (!directionsSuccessEvent || !startButtonPressed) { return; } var directions:Directions = directionsSuccessEvent.directions; // Extract the route. route = directions.getRoute(0); // Draws the polyline showing the route. polyline = directions.createPolyline(); addOverlay(directions.createPolyline()); // Creates a car marker that is moved along the route. var car:DisplayObject = new Car(); marker = new Marker(route.startGeocode.point, new MarkerOptions({ icon: car, iconOffset: new Point(-car.width / 2, -car.height) })); addOverlay(marker); transformPolyToWorld(); createCumulativeArrays(); // Load Panoramio data for the region covered by the route. loadPanoramioData(directions.bounds); var duration:Number = route.duration; // Start a timer that will trigger the car moving after the lead in time. var leadInTimer:Timer = new Timer(LEAD_IN_DURATION * 1000, 1); leadInTimer.addEventListener(TimerEvent.TIMER, onLeadInDone); leadInTimer.start(); var flyTime:Number = -LEAD_IN_DURATION; // Set up the camera flight trajectory. for each (var flyStep:Object in FLY_TRAJECTORY) { var time:Number = flyStep.fraction * duration; var center:LatLng = latLngAt(time); var scaledTime:Number = time * SCALE_TIME; var zoom:Number = flyStep.zoom; var attitude:Attitude = flyStep.attitude; var elapsed:Number = scaledTime - flyTime; flyTime = scaledTime; flyTo(center, zoom, attitude, elapsed); } } /** * Loads Panoramio data for the route bounds. We load data about more photos * than we need, then select a subset lying along the route. * @param bounds Bounds within which to fetch images. */ private function loadPanoramioData(bounds:LatLngBounds):void { var params:Object = { order: "popularity", set: "full", from: "0", to: NUM_GEOTAGGED_PHOTOS.toString(10), size: "small", minx: bounds.getWest(), miny: bounds.getSouth(), maxx: bounds.getEast(), maxy: bounds.getNorth() }; var loader:URLLoader = new URLLoader(); var request:URLRequest = new URLRequest( "http://www.panoramio.com/map/get_panoramas.php?" + paramsToString(params)); loader.addEventListener(Event.COMPLETE, onPanoramioDataLoaded); loader.addEventListener(IOErrorEvent.IO_ERROR, onPanoramioDataFailed); loader.load(request); } /** * Transforms the route polyline to world coordinates. */ private function transformPolyToWorld():void { var numVertices:int = polyline.getVertexCount(); worldPoly = new Array(numVertices); for (var i:int = 0; i < numVertices; ++i) { var vertex:LatLng = polyline.getVertex(i); worldPoly[i] = fromLatLngToPoint(vertex, 0); } } /** * Returns the time at which the route approaches closest to the * given point. * @param world Point in world coordinates. * @return Route time at which the closest approach occurs. */ private function getTimeOfClosestApproach(world:Point):Number { var minDistSqr:Number = Number.MAX_VALUE; var numVertices:int = worldPoly.length; var x:Number = world.x; var y:Number = world.y; var minVertex:int = 0; for (var i:int = 0; i < numVertices; ++i) { var dx:Number = worldPoly[i].x - x; var dy:Number = worldPoly[i].y - y; var distSqr:Number = dx * dx + dy * dy; if (distSqr < minDistSqr) { minDistSqr = distSqr; minVertex = i; } } return cumulativeVertexDistance[minVertex]; } /** * Returns the array index of the first element that compares greater than * the given value. * @param ordered Ordered array of elements. * @param value Value to use for comparison. * @return Array index of the first element that compares greater than * the given value. */ private function upperBound(ordered:Array, value:Number, first:int=0, last:int=-1):int { if (last < 0) { last = ordered.length; } var count:int = last - first; var index:int; while (count > 0) { var step:int = count >> 1; index = first + step; if (value >= ordered[index]) { first = index + 1; count -= step - 1; } else { count = step; } } return first; } /** * Selects up to a given number of photos approximately evenly spaced along * the route. * @param ordered Array of photos, each of which is an object with * a property &apos;closestTime&apos;. * @param number Number of photos to select. */ private function selectEvenlySpacedPhotos(ordered:Array, number:int):Array { var start:Number = cumulativeVertexDistance[0]; var end:Number = cumulativeVertexDistance[cumulativeVertexDistance.length - 2]; var closestTimes:Array = []; for each (var photo:Object in ordered) { closestTimes.push(photo.closestTime); } var selectedPhotos:Array = []; for (var i:int = 0; i < number; ++i) { var idealTime:Number = start + ((end - start) * (i + 0.5) / number); var index:int = upperBound(closestTimes, idealTime); if (index < 1) { index = 0; } else if (index >= ordered.length) { index = ordered.length - 1; } else { var errorToPrev:Number = Math.abs(idealTime - closestTimes[index - 1]); var errorToNext:Number = Math.abs(idealTime - closestTimes[index]); if (errorToPrev < errorToNext) { --index; } } selectedPhotos.push(ordered[index]); } return selectedPhotos; } /** * Handles completion of loading the Panoramio index data. Selects from the * returned photo indices a subset of those that lie along the route and * initiates load of each of these. * @param event Load completion event. */ private function onPanoramioDataLoaded(event:Event):void { var loader:URLLoader = event.target as URLLoader; var decoder:JSONDecoder = new JSONDecoder(loader.data as String); var allPhotos:Array = decoder.getValue().photos; for each (var photo:Object in allPhotos) { var latLng:LatLng = new LatLng(photo.latitude, photo.longitude); photo.closestTime = getTimeOfClosestApproach(fromLatLngToPoint(latLng, 0)); } allPhotos.sortOn("closestTime", Array.NUMERIC); photos = selectEvenlySpacedPhotos(allPhotos, NUM_SHOWN_PHOTOS); for each (photo in photos) { var photoLoader:Loader = new Loader(); // The images aren&apos;t on panoramio.com: we can&apos;t acquire pixel access // using "new LoaderContext(true)". photoLoader.load( new URLRequest(photo.photo_file_url)); photo.loader = photoLoader; // Save the loader info: we use this to find the original element when // the load completes. photo.loaderInfo = photoLoader.contentLoaderInfo; photoLoader.contentLoaderInfo.addEventListener( Event.COMPLETE, onPhotoLoaded); } } /** * Creates a MouseEvent listener function that will navigate to the given * URL in a new window. * @param url URL to which to navigate. */ private function createOnClickUrlOpener(url:String):Function { return function(event:MouseEvent):void { navigateToURL(new URLRequest(url)); }; } /** * Handles completion of loading an individual Panoramio image. * Adds a custom marker that displays the image. Initially this is made * invisible so that it can be faded in as needed. * @param event Load completion event. */ private function onPhotoLoaded(event:Event):void { var loaderInfo:LoaderInfo = event.target as LoaderInfo; // We need to find which photo element this image corresponds to. for each (var photo:Object in photos) { if (loaderInfo == photo.loaderInfo) { var imageMarker:Sprite = createImageMarker(photo.loader, photo.owner_name, photo.owner_url); var options:MarkerOptions = new MarkerOptions({ icon: imageMarker, hasShadow: true, iconAlignment: MarkerOptions.ALIGN_BOTTOM | MarkerOptions.ALIGN_LEFT }); var latLng:LatLng = new LatLng(photo.latitude, photo.longitude); var marker:Marker = new Marker(latLng, options); photo.marker = marker; addOverlay(marker); // A hack: we add the actual image after the overlay has been added, // which creates the shadow, so that the shadow is valid even if we // don&apos;t have security privileges to generate the shadow from the // image. marker.foreground.visible = false; marker.shadow.alpha = 0; var imageHolder:Sprite = new Sprite(); imageHolder.addChild(photo.loader); imageHolder.buttonMode = true; imageHolder.addEventListener( MouseEvent.CLICK, createOnClickUrlOpener(photo.photo_url)); imageMarker.addChild(imageHolder); return; } } trace("An image was loaded which could not be found in the photo array."); } /** * Creates a custom marker showing an image. */ private function createImageMarker(child:DisplayObject, ownerName:String, ownerUrl:String):Sprite { var content:Sprite = new Sprite(); var panoramioIcon:Bitmap = new PanoramioIcon(); var iconHolder:Sprite = new Sprite(); iconHolder.addChild(panoramioIcon); iconHolder.buttonMode = true; iconHolder.addEventListener(MouseEvent.CLICK, onPanoramioIconClick); panoramioIcon.x = BORDER_L; panoramioIcon.y = BORDER_T; content.addChild(iconHolder); // NOTE: we add the image as a child only after we&apos;ve added the marker // to the map. Currently the API requires this if it&apos;s to generate the // shadow for unprivileged content. // Shrink the image, so that it doesn&apos;t obcure too much screen space. // Ideally, we&apos;d subsample, but we don&apos;t have pixel level access. child.scaleX = IMAGE_SCALE; child.scaleY = IMAGE_SCALE; var imageW:Number = child.width; var imageH:Number = child.height; child.x = BORDER_L + 30; child.y = BORDER_T + iconHolder.height + GAP_T; var authorField:TextField = new TextField(); authorField.autoSize = TextFieldAutoSize.LEFT; authorField.defaultTextFormat = new TextFormat("_sans", 12); authorField.text = "author:"; content.addChild(authorField); authorField.x = BORDER_L; authorField.y = BORDER_T + iconHolder.height + GAP_T + imageH + GAP_B; var ownerField:TextField = new TextField(); ownerField.autoSize = TextFieldAutoSize.LEFT; var textFormat:TextFormat = new TextFormat("_sans", 14, 0x0e5f9a); ownerField.defaultTextFormat = textFormat; ownerField.htmlText = "<a href=\"" + ownerUrl + "\" target=\"_blank\">" + ownerName + "</a>"; content.addChild(ownerField); ownerField.x = BORDER_L + authorField.width; ownerField.y = BORDER_T + iconHolder.height + GAP_T + imageH + GAP_B; var totalW:Number = BORDER_L + Math.max(imageW, ownerField.width + authorField.width) + BORDER_R; var totalH:Number = BORDER_T + iconHolder.height + GAP_T + imageH + GAP_B + ownerField.height + BORDER_B; content.graphics.beginFill(0xffffff); content.graphics.drawRoundRect(0, 0, totalW, totalH, 10, 10); content.graphics.endFill(); var marker:Sprite = new Sprite(); marker.addChild(content); content.x = 30; content.y = 0; marker.graphics.lineStyle(); marker.graphics.beginFill(0xff0000); marker.graphics.drawCircle(0, totalH + 30, 3); marker.graphics.endFill(); marker.graphics.lineStyle(2, 0xffffff); marker.graphics.moveTo(30 + 10, totalH - 10); marker.graphics.lineTo(0, totalH + 30); return marker; } /** * Handles click on the Panoramio icon. */ private function onPanoramioIconClick(event:MouseEvent):void { navigateToURL(new URLRequest(PANORAMIO_HOME)); } /** * Handles failure of a Panoramio image load. */ private function onPanoramioDataFailed(event:IOErrorEvent):void { trace("Load of image failed: " + event); } /** * Returns a string containing cgi query parameters. * @param Associative array mapping query parameter key to value. * @return String containing cgi query parameters. */ private static function paramsToString(params:Object):String { var result:String = ""; var separator:String = ""; for (var key:String in params) { result += separator + encodeURIComponent(key) + "=" + encodeURIComponent(params[key]); separator = "&"; } return result; } /** * Called once the lead-in flight is done. Starts the car driving along * the route and starts a timer to begin fade in of the Panoramio * images in 1.5 seconds. */ private function onLeadInDone(event:Event):void { // Set startTimer non-zero so that the car starts to move. startTimer = getTimer(); // Start a timer that will fade in the Panoramio images. var fadeInTimer:Timer = new Timer(1500, 1); fadeInTimer.addEventListener(TimerEvent.TIMER, onFadeInTimer); fadeInTimer.start(); } /** * Handles the fade in timer&apos;s TIMER event. Sets markerAlpha above zero * which causes the frame enter handler to fade in the markers. */ private function onFadeInTimer(event:Event):void { markerAlpha = 0.01; } /** * The end time of the flight. */ private function get endTime():Number { if (!cumulativeStepDuration || cumulativeStepDuration.length == 0) { return startTimer; } return startTimer + cumulativeStepDuration[cumulativeStepDuration.length - 1]; } /** * Creates the cumulative arrays, cumulativeStepDuration and * cumulativeVertexDistance. */ private function createCumulativeArrays():void { cumulativeStepDuration = new Array(route.numSteps + 1); cumulativeVertexDistance = new Array(polyline.getVertexCount() + 1); var polylineTotal:Number = 0; var total:Number = 0; var numVertices:int = polyline.getVertexCount(); for (var stepIndex:int = 0; stepIndex < route.numSteps; ++stepIndex) { cumulativeStepDuration[stepIndex] = total; total += route.getStep(stepIndex).duration; var startVertex:int = stepIndex >= 0 ? route.getStep(stepIndex).polylineIndex : 0; var endVertex:int = stepIndex < (route.numSteps - 1) ? route.getStep(stepIndex + 1).polylineIndex : numVertices; var duration:Number = route.getStep(stepIndex).duration; var stepVertices:int = endVertex - startVertex; var latLng:LatLng = polyline.getVertex(startVertex); for (var vertex:int = startVertex; vertex < endVertex; ++vertex) { cumulativeVertexDistance[vertex] = polylineTotal; if (vertex < numVertices - 1) { var nextLatLng:LatLng = polyline.getVertex(vertex + 1); polylineTotal += nextLatLng.distanceFrom(latLng); } latLng = nextLatLng; } } cumulativeStepDuration[stepIndex] = total; } /** * Opens the info window above the car icon that details the given * step of the driving directions. * @param stepIndex Index of the current step. */ private function openInfoForStep(stepIndex:int):void { // Sets the content of the info window. var content:String; if (stepIndex >= route.numSteps) { content = "<b>" + route.endGeocode.address + "</b>" + "<br /><br />" + route.summaryHtml; } else { content = "<b>" + stepIndex + ".</b> " + route.getStep(stepIndex).descriptionHtml; } marker.openInfoWindow(new InfoWindowOptions({ contentHTML: content })); } /** * Displays the driving directions step appropriate for the given time. * Opens the info window showing the step instructions each time we * progress to a new step. * @param time Time for which to display the step. */ private function displayStepAt(time:Number):void { var stepIndex:int = upperBound(cumulativeStepDuration, time) - 1; var minStepIndex:int = 0; var maxStepIndex:int = route.numSteps - 1; if (stepIndex >= 0 && stepIndex <= maxStepIndex && currentStepIndex != stepIndex) { openInfoForStep(stepIndex); currentStepIndex = stepIndex; } } /** * Returns the LatLng at which the car should be positioned at the given * time. * @param time Time for which LatLng should be found. * @return LatLng. */ private function latLngAt(time:Number):LatLng { var stepIndex:int = upperBound(cumulativeStepDuration, time) - 1; var minStepIndex:int = 0; var maxStepIndex:int = route.numSteps - 1; if (stepIndex < minStepIndex) { return route.startGeocode.point; } else if (stepIndex > maxStepIndex) { return route.endGeocode.point; } var stepStart:Number = cumulativeStepDuration[stepIndex]; var stepEnd:Number = cumulativeStepDuration[stepIndex + 1]; var stepFraction:Number = (time - stepStart) / (stepEnd - stepStart); var startVertex:int = route.getStep(stepIndex).polylineIndex; var endVertex:int = (stepIndex + 1) < route.numSteps ? route.getStep(stepIndex + 1).polylineIndex : polyline.getVertexCount(); var stepVertices:int = endVertex - startVertex; var stepLeng

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  • Building applications with WPF, MVVM and Prism(aka CAG)

    - by skjagini
    In this article I am going to walk through an application using WPF and Prism (aka composite application guidance, CAG) which simulates engaging a taxi (cab).  The rules are simple, the app would have3 screens A login screen to authenticate the user An information screen. A screen to engage the cab and roam around and calculating the total fare Metered Rate of Fare The meter is required to be engaged when a cab is occupied by anyone $3.00 upon entry $0.35 for each additional unit The unit fare is: one-fifth of a mile, when the cab is traveling at 6 miles an hour or more; or 60 seconds when not in motion or traveling at less than 12 miles per hour. Night surcharge of $.50 after 8:00 PM & before 6:00 AM Peak hour Weekday Surcharge of $1.00 Monday - Friday after 4:00 PM & before 8:00 PM New York State Tax Surcharge of $.50 per ride. Example: Friday (2010-10-08) 5:30pm Start at Lexington Ave & E 57th St End at Irving Pl & E 15th St Start = $3.00 Travels 2 miles at less than 6 mph for 15 minutes = $3.50 Travels at more than 12 mph for 5 minutes = $1.75 Peak hour Weekday Surcharge = $1.00 (ride started at 5:30 pm) New York State Tax Surcharge = $0.50 Before we dive into the app, I would like to give brief description about the framework.  If you want to jump on to the source code, scroll all the way to the end of the post. MVVM MVVM pattern is in no way related to the usage of PRISM in your application and should be considered if you are using WPF irrespective of PRISM or not. Lets say you are not familiar with MVVM, your typical UI would involve adding some UI controls like text boxes, a button, double clicking on the button,  generating event handler, calling a method from business layer and updating the user interface, it works most of the time for developing small scale applications. The problem with this approach is that there is some amount of code specific to business logic wrapped in UI specific code which is hard to unit test it, mock it and MVVM helps to solve the exact problem. MVVM stands for Model(M) – View(V) – ViewModel(VM),  based on the interactions with in the three parties it should be called VVMM,  MVVM sounds more like MVC (Model-View-Controller) so the name. Why it should be called VVMM: View – View Model - Model WPF allows to create user interfaces using XAML and MVVM takes it to the next level by allowing complete separation of user interface and business logic. In WPF each view will have a property, DataContext when set to an instance of a class (which happens to be your view model) provides the data the view is interested in, i.e., view interacts with view model and at the same time view model interacts with view through DataContext. Sujith, if view and view model are interacting directly with each other how does MVVM is helping me separation of concerns? Well, the catch is DataContext is of type Object, since it is of type object view doesn’t know exact type of view model allowing views and views models to be loosely coupled. View models aggregate data from models (data access layer, services, etc) and make it available for views through properties, methods etc, i.e., View Models interact with Models. PRISM Prism is provided by Microsoft Patterns and Practices team and it can be downloaded from codeplex for source code,  samples and documentation on msdn.  The name composite implies, to compose user interface from different modules (views) without direct dependencies on each other, again allowing  loosely coupled development. Well Sujith, I can already do that with user controls, why shall I learn another framework?  That’s correct, you can decouple using user controls, but you still have to manage some amount of coupling, like how to do you communicate between the controls, how do you subscribe/unsubscribe, loading/unloading views dynamically. Prism is not a replacement for user controls, provides the following features which greatly help in designing the composite applications. Dependency Injection (DI)/ Inversion of Control (IoC) Modules Regions Event Aggregator  Commands Simply put, MVVM helps building a single view and Prism helps building an application using the views There are other open source alternatives to Prism, like MVVMLight, Cinch, take a look at them as well. Lets dig into the source code.  1. Solution The solution is made of the following projects Framework: Holds the common functionality in building applications using WPF and Prism TaxiClient: Start up project, boot strapping and app styling TaxiCommon: Helps with the business logic TaxiModules: Holds the meat of the application with views and view models TaxiTests: To test the application 2. DI / IoC Dependency Injection (DI) as the name implies refers to injecting dependencies and Inversion of Control (IoC) means the calling code has no direct control on the dependencies, opposite of normal way of programming where dependencies are passed by caller, i.e inversion; aside from some differences in terminology the concept is same in both the cases. The idea behind DI/IoC pattern is to reduce the amount of direct coupling between different components of the application, the higher the dependency the more tightly coupled the application resulting in code which is hard to modify, unit test and mock.  Initializing Dependency Injection through BootStrapper TaxiClient is the starting project of the solution and App (App.xaml)  is the starting class that gets called when you run the application. From the App’s OnStartup method we will invoke BootStrapper.   namespace TaxiClient { /// <summary> /// Interaction logic for App.xaml /// </summary> public partial class App : Application { protected override void OnStartup(StartupEventArgs e) { base.OnStartup(e);   (new BootStrapper()).Run(); } } } BootStrapper is your contact point for initializing the application including dependency injection, creating Shell and other frameworks. We are going to use Unity for DI and there are lot of open source DI frameworks like Spring.Net, StructureMap etc with different feature set  and you can choose a framework based on your preferences. Note that Prism comes with in built support for Unity, for example we are deriving from UnityBootStrapper in our case and for any other DI framework you have to extend the Prism appropriately   namespace TaxiClient { public class BootStrapper: UnityBootstrapper { protected override IModuleCatalog CreateModuleCatalog() { return new ConfigurationModuleCatalog(); } protected override DependencyObject CreateShell() { Framework.FrameworkBootStrapper.Run(Container, Application.Current.Dispatcher);   Shell shell = new Shell(); shell.ResizeMode = ResizeMode.NoResize; shell.Show();   return shell; } } } Lets take a look into  FrameworkBootStrapper to check out how to register with unity container. namespace Framework { public class FrameworkBootStrapper { public static void Run(IUnityContainer container, Dispatcher dispatcher) { UIDispatcher uiDispatcher = new UIDispatcher(dispatcher); container.RegisterInstance<IDispatcherService>(uiDispatcher);   container.RegisterType<IInjectSingleViewService, InjectSingleViewService>( new ContainerControlledLifetimeManager());   . . . } } } In the above code we are registering two components with unity container. You shall observe that we are following two different approaches, RegisterInstance and RegisterType.  With RegisterInstance we are registering an existing instance and the same instance will be returned for every request made for IDispatcherService   and with RegisterType we are requesting unity container to create an instance for us when required, i.e., when I request for an instance for IInjectSingleViewService, unity will create/return an instance of InjectSingleViewService class and with RegisterType we can configure the life time of the instance being created. With ContaienrControllerLifetimeManager, the unity container caches the instance and reuses for any subsequent requests, without recreating a new instance. Lets take a look into FareViewModel.cs and it’s constructor. The constructor takes one parameter IEventAggregator and if you try to find all references in your solution for IEventAggregator, you will not find a single location where an instance of EventAggregator is passed directly to the constructor. The compiler still finds an instance and works fine because Prism is already configured when used with Unity container to return an instance of EventAggregator when requested for IEventAggregator and in this particular case it is called constructor injection. public class FareViewModel:ObservableBase, IDataErrorInfo { ... private IEventAggregator _eventAggregator;   public FareViewModel(IEventAggregator eventAggregator) { _eventAggregator = eventAggregator; InitializePropertyNames(); InitializeModel(); PropertyChanged += OnPropertyChanged; } ... 3. Shell Shells are very similar in operation to Master Pages in asp.net or MDI in Windows Forms. And shells contain regions which display the views, you can have as many regions as you wish in a given view. You can also nest regions. i.e, one region can load a view which in itself may contain other regions. We have to create a shell at the start of the application and are doing it by overriding CreateShell method from BootStrapper From the following Shell.xaml you shall notice that we have two content controls with Region names as ‘MenuRegion’ and ‘MainRegion’.  The idea here is that you can inject any user controls into the regions dynamically, i.e., a Menu User Control for MenuRegion and based on the user action you can load appropriate view into MainRegion.    <Window x:Class="TaxiClient.Shell" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:Regions="clr-namespace:Microsoft.Practices.Prism.Regions;assembly=Microsoft.Practices.Prism" Title="Taxi" Height="370" Width="800"> <Grid Margin="2"> <ContentControl Regions:RegionManager.RegionName="MenuRegion" HorizontalAlignment="Stretch" VerticalAlignment="Stretch" HorizontalContentAlignment="Stretch" VerticalContentAlignment="Stretch" />   <ContentControl Grid.Row="1" Regions:RegionManager.RegionName="MainRegion" HorizontalAlignment="Stretch" VerticalAlignment="Stretch" HorizontalContentAlignment="Stretch" VerticalContentAlignment="Stretch" /> <!--<Border Grid.ColumnSpan="2" BorderThickness="2" CornerRadius="3" BorderBrush="LightBlue" />-->   </Grid> </Window> 4. Modules Prism provides the ability to build composite applications and modules play an important role in it. For example if you are building a Mortgage Loan Processor application with 3 components, i.e. customer’s credit history,  existing mortgages, new home/loan information; and consider that the customer’s credit history component involves gathering data about his/her address, background information, job details etc. The idea here using Prism modules is to separate the implementation of these 3 components into their own visual studio projects allowing to build components with no dependency on each other and independently. If we need to add another component to the application, the component can be developed by in house team or some other team in the organization by starting with a new Visual Studio project and adding to the solution at the run time with very little knowledge about the application. Prism modules are defined by implementing the IModule interface and each visual studio project to be considered as a module should implement the IModule interface.  From the BootStrapper.cs you shall observe that we are overriding the method by returning a ConfiguratingModuleCatalog which returns the modules that are registered for the application using the app.config file  and you can also add module using code. Lets take a look into configuration file.   <?xml version="1.0"?> <configuration> <configSections> <section name="modules" type="Microsoft.Practices.Prism.Modularity.ModulesConfigurationSection, Microsoft.Practices.Prism"/> </configSections> <modules> <module assemblyFile="TaxiModules.dll" moduleType="TaxiModules.ModuleInitializer, TaxiModules" moduleName="TaxiModules"/> </modules> </configuration> Here we are adding TaxiModules project to our solution and TaxiModules.ModuleInitializer implements IModule interface   5. Module Mapper With Prism modules you can dynamically add or remove modules from the regions, apart from that Prism also provides API to control adding/removing the views from a region within the same module. Taxi Information Screen: Engage the Taxi Screen: The sample application has two screens, ‘Taxi Information’ and ‘Engage the Taxi’ and they both reside in same module, TaxiModules. ‘Engage the Taxi’ is again made of two user controls, FareView on the left and TotalView on the right. We have created a Shell with two regions, MenuRegion and MainRegion with menu loaded into MenuRegion. We can create a wrapper user control called EngageTheTaxi made of FareView and TotalView and load either TaxiInfo or EngageTheTaxi into MainRegion based on the user action. Though it will work it tightly binds the user controls and for every combination of user controls, we need to create a dummy wrapper control to contain them. Instead we can apply the principles we learned so far from Shell/regions and introduce another template (LeftAndRightRegionView.xaml) made of two regions Region1 (left) and Region2 (right) and load  FareView and TotalView dynamically.  To help with loading of the views dynamically I have introduce an helper an interface, IInjectSingleViewService,  idea suggested by Mike Taulty, a must read blog for .Net developers. using System; using System.Collections.Generic; using System.ComponentModel;   namespace Framework.PresentationUtility.Navigation {   public interface IInjectSingleViewService : INotifyPropertyChanged { IEnumerable<CommandViewDefinition> Commands { get; } IEnumerable<ModuleViewDefinition> Modules { get; }   void RegisterViewForRegion(string commandName, string viewName, string regionName, Type viewType); void ClearViewFromRegion(string viewName, string regionName); void RegisterModule(string moduleName, IList<ModuleMapper> moduleMappers); } } The Interface declares three methods to work with views: RegisterViewForRegion: Registers a view with a particular region. You can register multiple views and their regions under one command.  When this particular command is invoked all the views registered under it will be loaded into their regions. ClearViewFromRegion: To unload a specific view from a region. RegisterModule: The idea is when a command is invoked you can load the UI with set of controls in their default position and based on the user interaction, you can load different contols in to different regions on the fly.  And it is supported ModuleViewDefinition and ModuleMappers as shown below. namespace Framework.PresentationUtility.Navigation { public class ModuleViewDefinition { public string ModuleName { get; set; } public IList<ModuleMapper> ModuleMappers; public ICommand Command { get; set; } }   public class ModuleMapper { public string ViewName { get; set; } public string RegionName { get; set; } public Type ViewType { get; set; } } } 6. Event Aggregator Prism event aggregator enables messaging between components as in Observable pattern, Notifier notifies the Observer which receives notification it is interested in. When it comes to Observable pattern, Observer has to unsubscribes for notifications when it no longer interested in notifications, which allows the Notifier to remove the Observer’s reference from it’s local cache. Though .Net has managed garbage collection it cannot remove inactive the instances referenced by an active instance resulting in memory leak, keeping the Observers in memory as long as Notifier stays in memory.  Developers have to be very careful to unsubscribe when necessary and it often gets overlooked, to overcome these problems Prism Event Aggregator uses weak references to cache the reference (Observer in this case)  and releases the reference (memory) once the instance goes out of scope. Using event aggregator is very simple, declare a generic type of CompositePresenationEvent by inheriting from it. using Microsoft.Practices.Prism.Events; using TaxiCommon.BAO;   namespace TaxiCommon.CompositeEvents { public class TaxiOnMoveEvent:CompositePresentationEvent<TaxiOnMove> { } }   TaxiOnMove.cs includes the properties which we want to exchange between the parties, FareView and TotalView. using System;   namespace TaxiCommon.BAO { public class TaxiOnMove { public TimeSpan MinutesAtTweleveMPH { get; set; } public double MilesAtSixMPH { get; set; } } }   Lets take a look into FareViewodel (Notifier) and how it raises the event.  Here we are raising the event by getting the event through GetEvent<..>() and publishing it with the payload private void OnAddMinutes(object obj) { TaxiOnMove payload = new TaxiOnMove(); if(MilesAtSixMPH != null) payload.MilesAtSixMPH = MilesAtSixMPH.Value; if(MinutesAtTweleveMPH != null) payload.MinutesAtTweleveMPH = new TimeSpan(0,0,MinutesAtTweleveMPH.Value,0);   _eventAggregator.GetEvent<TaxiOnMoveEvent>().Publish(payload); ResetMinutesAndMiles(); } And TotalViewModel(Observer) subscribes to notifications by getting the event through GetEvent<..>() namespace TaxiModules.ViewModels { public class TotalViewModel:ObservableBase { .... private IEventAggregator _eventAggregator;   public TotalViewModel(IEventAggregator eventAggregator) { _eventAggregator = eventAggregator; ... }   private void SubscribeToEvents() { _eventAggregator.GetEvent<TaxiStartedEvent>() .Subscribe(OnTaxiStarted, ThreadOption.UIThread,false,(filter) => true); _eventAggregator.GetEvent<TaxiOnMoveEvent>() .Subscribe(OnTaxiMove, ThreadOption.UIThread, false, (filter) => true); _eventAggregator.GetEvent<TaxiResetEvent>() .Subscribe(OnTaxiReset, ThreadOption.UIThread, false, (filter) => true); }   ... private void OnTaxiMove(TaxiOnMove taxiOnMove) { OnMoveFare fare = new OnMoveFare(taxiOnMove); Fares.Add(fare); SetTotalFare(new []{fare}); }   .... 7. MVVM through example In this section we are going to look into MVVM implementation through example.  I have all the modules declared in a single project, TaxiModules, again it is not necessary to have them into one project. Once the user logs into the application, will be greeted with the ‘Engage the Taxi’ screen which is made of two user controls, FareView.xaml and TotalView.Xaml. As you can see from the solution explorer, each of them have their own code behind files and  ViewModel classes, FareViewMode.cs, TotalViewModel.cs Lets take a look in to the FareView and how it interacts with FareViewModel using MVVM implementation. FareView.xaml acts as a view and FareViewMode.cs is it’s view model. The FareView code behind class   namespace TaxiModules.Views { /// <summary> /// Interaction logic for FareView.xaml /// </summary> public partial class FareView : UserControl { public FareView(FareViewModel viewModel) { InitializeComponent(); this.Loaded += (s, e) => { this.DataContext = viewModel; }; } } } The FareView is bound to FareViewModel through the data context  and you shall observe that DataContext is of type Object, i.e. the FareView doesn’t really know the type of ViewModel (FareViewModel). This helps separation of View and ViewModel as View and ViewModel are independent of each other, you can bind FareView to FareViewModel2 as well and the application compiles just fine. Lets take a look into FareView xaml file  <UserControl x:Class="TaxiModules.Views.FareView" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:Toolkit="clr-namespace:Microsoft.Windows.Controls;assembly=WPFToolkit" xmlns:Commands="clr-namespace:Microsoft.Practices.Prism.Commands;assembly=Microsoft.Practices.Prism"> <Grid Margin="10" > ....   <Border Style="{DynamicResource innerBorder}" Grid.Row="0" Grid.Column="0" Grid.RowSpan="11" Grid.ColumnSpan="2" Panel.ZIndex="1"/>   <Label Grid.Row="0" Content="Engage the Taxi" Style="{DynamicResource innerHeader}"/> <Label Grid.Row="1" Content="Select the State"/> <ComboBox Grid.Row="1" Grid.Column="1" ItemsSource="{Binding States}" Height="auto"> <ComboBox.ItemTemplate> <DataTemplate> <TextBlock Text="{Binding Name}"/> </DataTemplate> </ComboBox.ItemTemplate> <ComboBox.SelectedItem> <Binding Path="SelectedState" Mode="TwoWay"/> </ComboBox.SelectedItem> </ComboBox> <Label Grid.Row="2" Content="Select the Date of Entry"/> <Toolkit:DatePicker Grid.Row="2" Grid.Column="1" SelectedDate="{Binding DateOfEntry, ValidatesOnDataErrors=true}" /> <Label Grid.Row="3" Content="Enter time 24hr format"/> <TextBox Grid.Row="3" Grid.Column="1" Text="{Binding TimeOfEntry, TargetNullValue=''}"/> <Button Grid.Row="4" Grid.Column="1" Content="Start the Meter" Commands:Click.Command="{Binding StartMeterCommand}" />   <Label Grid.Row="5" Content="Run the Taxi" Style="{DynamicResource innerHeader}"/> <Label Grid.Row="6" Content="Number of Miles &lt;@6mph"/> <TextBox Grid.Row="6" Grid.Column="1" Text="{Binding MilesAtSixMPH, TargetNullValue='', ValidatesOnDataErrors=true}"/> <Label Grid.Row="7" Content="Number of Minutes @12mph"/> <TextBox Grid.Row="7" Grid.Column="1" Text="{Binding MinutesAtTweleveMPH, TargetNullValue=''}"/> <Button Grid.Row="8" Grid.Column="1" Content="Add Minutes and Miles " Commands:Click.Command="{Binding AddMinutesCommand}"/> <Label Grid.Row="9" Content="Other Operations" Style="{DynamicResource innerHeader}"/> <Button Grid.Row="10" Grid.Column="1" Content="Reset the Meter" Commands:Click.Command="{Binding ResetCommand}"/>   </Grid> </UserControl> The highlighted code from the above code shows data binding, for example ComboBox which displays list of states has it’s ItemsSource bound to States property, with DataTemplate bound to Name and SelectedItem  to SelectedState. You might be wondering what are all these properties and how it is able to bind to them.  The answer lies in data context, i.e., when you bound a control, WPF looks for data context on the root object (Grid in this case) and if it can’t find data context it will look into root’s root, i.e. FareView UserControl and it is bound to FareViewModel.  Each of those properties have be declared on the ViewModel for the View to bind correctly. To put simply, View is bound to ViewModel through data context of type object and every control that is bound on the View actually binds to the public property on the ViewModel. Lets look into the ViewModel code (the following code is not an exact copy of FareViewMode.cs, pasted relevant code for this section)   namespace TaxiModules.ViewModels { public class FareViewModel:ObservableBase, IDataErrorInfo { public List<USState> States { get { return USStates.StateList; } }   public USState SelectedState { get { return _selectedState; } set { _selectedState = value; RaisePropertyChanged(_selectedStatePropertyName); } }   public DateTime? DateOfEntry { get { return _dateOfEntry; } set { _dateOfEntry = value; RaisePropertyChanged(_dateOfEntryPropertyName); } }   public TimeSpan? TimeOfEntry { get { return _timeOfEntry; } set { _timeOfEntry = value; RaisePropertyChanged(_timeOfEntryPropertyName); } }   public double? MilesAtSixMPH { get { return _milesAtSixMPH; } set { _milesAtSixMPH = value; RaisePropertyChanged(_distanceAtSixMPHPropertyName); } }   public int? MinutesAtTweleveMPH { get { return _minutesAtTweleveMPH; } set { _minutesAtTweleveMPH = value; RaisePropertyChanged(_minutesAtTweleveMPHPropertyName); } }   public ICommand StartMeterCommand { get { if(_startMeterCommand == null) { _startMeterCommand = new DelegateCommand<object>(OnStartMeter, CanStartMeter); } return _startMeterCommand; } }   public ICommand AddMinutesCommand { get { if(_addMinutesCommand == null) { _addMinutesCommand = new DelegateCommand<object>(OnAddMinutes, CanAddMinutes); } return _addMinutesCommand; } }   public ICommand ResetCommand { get { if(_resetCommand == null) { _resetCommand = new DelegateCommand<object>(OnResetCommand); } return _resetCommand; } }   } private void OnStartMeter(object obj) { _eventAggregator.GetEvent<TaxiStartedEvent>().Publish( new TaxiStarted() { EngagedOn = DateOfEntry.Value.Date + TimeOfEntry.Value, EngagedState = SelectedState.Value });   _isMeterStarted = true; OnPropertyChanged(this,null); } And views communicate user actions like button clicks, tree view item selections, etc using commands. When user clicks on ‘Start the Meter’ button it invokes the method StartMeterCommand, which calls the method OnStartMeter which publishes the event to TotalViewModel using event aggregator  and TaxiStartedEvent. namespace TaxiModules.ViewModels { public class TotalViewModel:ObservableBase { ... private IEventAggregator _eventAggregator;   public TotalViewModel(IEventAggregator eventAggregator) { _eventAggregator = eventAggregator;   InitializePropertyNames(); InitializeModel(); SubscribeToEvents(); }   public decimal? TotalFare { get { return _totalFare; } set { _totalFare = value; RaisePropertyChanged(_totalFarePropertyName); } } .... private void SubscribeToEvents() { _eventAggregator.GetEvent<TaxiStartedEvent>().Subscribe(OnTaxiStarted, ThreadOption.UIThread,false,(filter) => true); _eventAggregator.GetEvent<TaxiOnMoveEvent>().Subscribe(OnTaxiMove, ThreadOption.UIThread, false, (filter) => true); _eventAggregator.GetEvent<TaxiResetEvent>().Subscribe(OnTaxiReset, ThreadOption.UIThread, false, (filter) => true); }   private void OnTaxiStarted(TaxiStarted taxiStarted) { Fares.Add(new EntryFare()); Fares.Add(new StateTaxFare(taxiStarted)); Fares.Add(new NightSurchargeFare(taxiStarted)); Fares.Add(new PeakHourWeekdayFare(taxiStarted));   SetTotalFare(Fares); }   private void SetTotalFare(IEnumerable<IFare> fares) { TotalFare = (_totalFare ?? 0) + TaxiFareHelper.GetTotalFare(fares); } ....   } }   TotalViewModel subscribes to events, TaxiStartedEvent and rest. When TaxiStartedEvent gets invoked it calls the OnTaxiStarted method which sets the total fare which includes entry fee, state tax, nightly surcharge, peak hour weekday fare.   Note that TotalViewModel derives from ObservableBase which implements the method RaisePropertyChanged which we are invoking in Set of TotalFare property, i.e, once we update the TotalFare property it raises an the event that  allows the TotalFare text box to fetch the new value through the data context. ViewModel is communicating with View through data context and it has no knowledge about View, helping in loose coupling of ViewModel and View.   I have attached the source code (.Net 4.0, Prism 4.0, VS 2010) , download and play with it and don’t forget to leave your comments.  

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  • How do I set the encoding statement in the XML declaration when performing an XSL transformation usi

    - by aspiehler
    I wrote a simple package installer in WinBatch that needs to update an XML file with information about the package contents. My first stab at it involved loading the file with Msxml2.DOMDocument, adding nodes and data as required, then saving the data back to disk. This worked well enough, except that it would not create tab and CR/LF whitespace in the new data. The solution I came up with was writing an XSL stylesheet that would recreate the XML file with whitespace added back in. I'm doing this by: loading the XSL file into an Msxml2.FreeThreadedDOMDocument object setting that object as the stylesheet property of an Msxml2.XSLTemplate object creating an XSL processor via Msxml2.XSLTemplate.createProcessor() setting my original Msxml2.DOMDocument as the input property of the XSL processor Calling transform() method of the XSL processor, and saving the output to a file. This works as for as reformatting the XML file with tabs and carriage returns, but my XML declaration comes out either as <?xml version="1.0"?> or <?xml version="1.0" encoding="UTF-16"?> depending on whether I used Msxml2.*.6.0 or Msxml2.* objects (a fall back if the system doesn't have 6.0). If the encoding is set to UTF-16, Msxml12.DOMDocument complains about trying to convert UTF-16 to 1-byte encoding the next time I run my package installer. I've tried creating and adding an XML declaration using both createProcessingInstruction() to both the XML and XSL DOM objects, but neither one seems to affect the output of the XSLTemplate processor. I've also set encoding to UTF-8 in the <xsl:output/> tag in my XSL file. Here is the relevant code in my Winbatch script: xmlDoc = ObjectCreate("Msxml2.DOMDocument.6.0") if !xmlDoc then xmlDoc = ObjectCreate("Msxml2.DOMDocument") xmlDoc.async = @FALSE xmlDoc.validateOnParse = @TRUE xmlDoc.resolveExternals = @TRUE xmlDoc.preserveWhiteSpace = @TRUE xmlDoc.setProperty("SelectionLanguge", "XPath") xmlDoc.setProperty("SelectionNamespaces", "xmlns:fns='http://www.abc.com/f_namespace'") xmlDoc.load(xml_file_path) xslStyleSheet = ObjectCreate("Msxml2.FreeThreadedDOMDocument.6.0") if !xslStyleSheet then xslStyleSheet = ObjectCreate("Msxml2.FreeThreadedDOMDocument") xslStyleSheet.async = @FALSE xslStyleSheet.validateOnParse = @TRUE xslStyleSheet.load(xsl_style_sheet_path) xslTemplate = ObjectCreate("Msxml2.XSLTemplate.6.0") if !xslTemplate then xslTemplate = ObjectCreate("Msxml2.XSLTemplate") xslTemplate.stylesheet = xslStyleSheet processor = xslTemplate.createProcessor() processor.input = xmlDoc processor.transform() ; create a new file and write the XML processor output to it fh = FileOpen(output_file_path, "WRITE" , @FALSE) FileWrite(fh, processor.output) FileClose(fh) The style sheet, with some slight changes to protect the innocent: <?xml version="1.0" encoding="UTF-8"?> <xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform" version="1.1"> <xsl:output method="xml" indent="yes" encoding="UTF-8"/> <xsl:template match="/"> <fns:test_station xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:fns="http://www.abc.com/f_namespace"> <xsl:for-each select="/fns:test_station/identification"> <xsl:text>&#x0A; </xsl:text> <identification> <xsl:for-each select="./*"> <xsl:text>&#x0A; </xsl:text> <xsl:copy-of select="."/> </xsl:for-each> <xsl:text>&#x0A; </xsl:text> </identification> </xsl:for-each> <xsl:for-each select="/fns:test_station/software"> <xsl:text>&#x0A; </xsl:text> <software> <xsl:for-each select="./package"> <xsl:text>&#x0A; </xsl:text> <package> <xsl:for-each select="./*"> <xsl:text>&#x0A; </xsl:text> <xsl:copy-of select="."/> </xsl:for-each> <xsl:text>&#x0A; </xsl:text> </package> </xsl:for-each> <xsl:text>&#x0A; </xsl:text> </software> </xsl:for-each> <xsl:for-each select="/fns:test_station/calibration"> <xsl:text>&#x0A; </xsl:text> <calibration> <xsl:for-each select="./item"> <xsl:text>&#x0A; </xsl:text> <item> <xsl:for-each select="./*"> <xsl:text>&#x0A; </xsl:text> <xsl:copy-of select="."/> </xsl:for-each> <xsl:text>&#x0A; </xsl:text> </item> </xsl:for-each> <xsl:text>&#x0A; </xsl:text> </calibration> </xsl:for-each> </fns:test_station> </xsl:template> </xsl:stylesheet> And this is a sample output file: <?xml version="1.0" encoding="UTF-16"?> <fns:test_station xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:fns="http://www.abc.com/f_namespace"> <software> <package> <part_number>123456789</part_number> <version>00</version> <test_category>1</test_category> <description>name of software package</description> <execution_path>c:\program files\test\test.exe</execution_path> <execution_arguments>arguments</execution_arguments> <crc_path>c:\ste_config\crc\123456789.lst</crc_path> <uninstall_path>c:\ste_config\uninstall\uninst_123456789.bat</uninstall_path> <install_timestamp>2009-11-09T14:00:44</install_timestamp> </package> </software> </fns:test_station>

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  • half or quarter black screen in android

    - by Mike McKeown
    I have an android activity that when I launch sometimes (about 1 in 4 times) it only draws quarter or half the screen before showing it. When I change the orientation or press a button the screen draws properly. I'm just using TextViews, Buttons, Fonts - no drawing or anything like that. All of my code for initialising is in the onCreate(). In this method I'm loading a text file, of about 40 lines long, and also getting a shared preference. Could this cause a delay so that it can't draw the intent? Thanks in advance if anyone has seen anything similar. EDIT - I tried commenting out the loading of the word list, but it didn't fix the problem. Here is the activity <?xml version="1.0" encoding="utf-8"?> <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" android:id="@+id/mainRelativeLayout" android:layout_width="fill_parent" android:layout_height="fill_parent" android:background="@drawable/blue_abstract_background" > <RelativeLayout android:id="@+id/relativeScore" android:layout_width="fill_parent" android:layout_height="wrap_content" android:gravity="center_horizontal" > <TextView android:id="@+id/ScoreLabel" style="@style/yellowShadowText" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_alignParentLeft="true" android:layout_centerVertical="true" android:padding="10dip" android:text="SCORE:" android:textSize="18dp" /> /> <TextView android:id="@+id/ScoreText" style="@style/yellowShadowText" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_centerVertical="true" android:layout_toRightOf="@id/ScoreLabel" android:padding="5dip" android:text="0" android:textSize="18dp" /> <TextView android:id="@+id/GameTimerText" style="@style/yellowShadowText" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_alignParentRight="true" android:layout_centerVertical="true" android:layout_marginLeft="5dp" android:layout_marginRight="5dp" android:minWidth="25dp" android:text="0" android:textSize="18dp" /> <TextView android:id="@+id/GameTimerLabel" style="@style/yellowShadowText" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_centerVertical="true" android:layout_toLeftOf="@id/GameTimerText" android:padding="10dip" android:text="TIMER:" android:textSize="18dp" /> /> </RelativeLayout> <RelativeLayout android:id="@+id/relativeHighScore" android:layout_width="fill_parent" android:layout_height="wrap_content" android:layout_below="@id/relativeScore" > <TextView android:id="@+id/HighScoreLabel" style="@style/yellowShadowText" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_alignParentLeft="true" android:padding="10dip" android:text="HIGH SCORE:" android:textSize="16dp" /> <TextView android:id="@+id/HighScoreText" style="@style/yellowShadowText" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_toRightOf="@id/HighScoreLabel" android:padding="10dip" android:text="0" android:textSize="16dp" /> </RelativeLayout> <LinearLayout android:layout_width="fill_parent" android:layout_height="fill_parent" android:layout_alignParentLeft="true" android:layout_below="@+id/relativeHighScore" android:orientation="vertical" > <LinearLayout android:id="@+id/linearMissing" android:layout_width="fill_parent" android:layout_height="80dp" android:layout_gravity="center" android:orientation="vertical" > <View android:layout_width="match_parent" android:layout_height="2dp" android:background="@color/yellow_text" /> <TextView android:id="@+id/MissingWordText" style="@style/yellowShadowText" android:layout_width="wrap_content" android:layout_height="fill_parent" android:layout_gravity="center_horizontal" android:layout_marginTop="25dp" android:text="MSSNG WRD" android:textSize="22dp" android:typeface="normal" /> </LinearLayout> <View android:layout_width="match_parent" android:layout_height="2dp" android:background="@color/yellow_text" /> <TableLayout android:id="@+id/buttonsTableLayout" android:layout_width="fill_parent" android:layout_height="wrap_content" > <TableRow android:id="@+id/tableRow3" android:layout_width="fill_parent" android:layout_height="wrap_content" android:gravity="center_horizontal" android:paddingTop="5dp" > <Button android:id="@+id/aVowelButton" android:layout_width="66dp" android:layout_height="66dp" android:layout_gravity="center_horizontal" android:layout_marginBottom="10dp" android:layout_marginRight="5dp" android:background="@drawable/blue_vowel_button" android:text="@string/a" android:textColor="@color/yellow_text" android:textSize="30dp" /> <Button android:id="@+id/eVowelButton" android:layout_width="66dp" android:layout_height="66dp" android:layout_gravity="center_horizontal" android:layout_marginBottom="10dp" android:layout_marginRight="5dp" android:background="@drawable/blue_vowel_button" android:text="@string/e" android:textColor="@color/yellow_text" android:textSize="30dp" /> </TableRow> <TableRow android:id="@+id/tableRow4" android:layout_width="fill_parent" android:layout_height="wrap_content" android:gravity="center_horizontal" > <Button android:id="@+id/iVowelButton" android:layout_width="66dp" android:layout_height="66dp" android:layout_gravity="center_horizontal" android:layout_margin="5dp" android:background="@drawable/blue_vowel_buttoni" android:text="@string/i" android:textColor="@color/yellow_text" android:textSize="30dp" /> <Button android:id="@+id/oVowelButton" android:layout_width="66dp" android:layout_height="66dp" android:layout_gravity="center_horizontal" android:layout_margin="5dp" android:background="@drawable/blue_vowel_button" android:text="@string/o" android:textColor="@color/yellow_text" android:textSize="30dp" /> <Button android:id="@+id/uVowelButton" android:layout_width="66dp" android:layout_height="66dp" android:layout_gravity="center_horizontal" android:layout_margin="5dp" android:background="@drawable/blue_vowel_button" android:text="@string/u" android:textColor="@color/yellow_text" android:textSize="30dp" /> </TableRow> </TableLayout> <TextView android:id="@+id/TimeToStartText" style="@style/yellowShadowText" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_gravity="center" android:textSize="24dp" /> <Button android:id="@+id/startButton" style="@style/yellowShadowText" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_gravity="center_horizontal" android:layout_marginTop="10dp" android:background="@drawable/blue_button_menu" android:gravity="center" android:padding="10dip" android:text="START!" android:textSize="28dp" /> </LinearLayout> </RelativeLayout> And the OnCreate() and a few methods: public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_game); isNewWord = true; m_gameScore = 0; m_category = getCategoryFromExtras(); // loadWordList(m_category); initialiseTextViewField(); loadHighScoreAndDifficulty(); setFonts(); setButtons(); setStartButton(); enableDisableButtons(false); } private void loadHighScoreAndDifficulty() { //setting preferences SharedPreferences prefs = this.getSharedPreferences(m_category, Context.MODE_PRIVATE); int score = prefs.getInt(m_category, 0); //0 is the default value m_highScore = score; m_highScoreText.setText(String.valueOf(m_highScore)); prefs = this.getSharedPreferences(DIFFICULTY, Context.MODE_PRIVATE); m_difficulty = prefs.getString(DIFFICULTY, NRML_DIFFICULTY); } private void initialiseTextViewField() { m_startButton = (Button) findViewById(R.id.startButton); m_missingWordText = (TextView) findViewById(R.id.MissingWordText); m_gameScoreText = (TextView) findViewById(R.id.ScoreText); m_gameScoreLabel = (TextView) findViewById(R.id.ScoreLabel); m_gameTimerText = (TextView) findViewById(R.id.GameTimerText); m_gameTimerLabel = (TextView) findViewById(R.id.GameTimerLabel); m_timeToStartText = (TextView) findViewById(R.id.TimeToStartText); m_highScoreLabel = (TextView) findViewById(R.id.HighScoreLabel); m_highScoreText = (TextView) findViewById(R.id.HighScoreText); } private String getCategoryFromExtras() { String category = ""; Bundle extras = getIntent().getExtras(); if (extras != null) { category = extras.getString("category"); } return category; } private void enableDisableButtons(boolean enable) { Button button = (Button) findViewById(R.id.aVowelButton); button.setEnabled(enable); button = (Button) findViewById(R.id.eVowelButton); button.setEnabled(enable); button = (Button) findViewById(R.id.iVowelButton); button.setEnabled(enable); button = (Button) findViewById(R.id.oVowelButton); button.setEnabled(enable); button = (Button) findViewById(R.id.uVowelButton); button.setEnabled(enable); } private void setStartButton() { m_startButton.setOnClickListener(new View.OnClickListener() { public void onClick(View view) { m_gameScore = 0; updateScore(); m_startButton.setVisibility(View.GONE); m_timeToStartText.setVisibility(View.VISIBLE); startPreTimer(); } }); }

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  • Anyone have ideas for solving the "n items remaining" problem on Internet Explorer?

    - by CMPalmer
    In my ASP.Net app, which is javascript and jQuery heavy, but also uses master pages and .Net Ajax pieces, I am consistently seeing on the status bar of IE 6 (and occasionally IE 7) the message "2 items remaining" or "15 items remaining" followed by "loading somegraphicsfile.png|gif ." This message never goes away and may or may not prevent some page functionality from running (it certainly seems to bog down, but I'm not positive). I can cause this to happen 99% of the time by just refreshing an .aspx age, but the number of items and, sometimes, the file it mentions varies. Usually it is 2, 3, 12, 13, or 15. I've Googled for answers and there are several suggestions or explanations. Some of them haven't worked for us, and others aren't practical for us to implement or try. Here are some of the ideas/theories: IE isn't caching images right, so it repeatedly asks for the same image if the image is repeated on the page and the server assumes that it should be cached locally since it's already served it in that page context. IE displays the images correctly, but sits and waits for a server response that never comes. Typically the file it says it is waiting on is repeated on the page. The page is using PNG graphics with transparency. Indeed it is, but they are jQuery-UI Themeroller generated graphics which, according to the jQuery-UI folks, are IE safe. The jQuery-UI components are the only things using PNGs. All of our PNG references are in CSS, if that helps. I've changed some of the graphics from PNG to GIF, but it is just as likely to say it's waiting for somegraphicsfile.png as it is for somegraphicsfile.gif Images are being specified in CSS and/or JavaScript but are on things that aren't currently being displayed (display: none items for example). This may be true, but if it is, then I would think preloading images would work, but so far, adding a preloader doesn't do any good. IIS's caching policy is confusing the browser. If this is true, it is only Microsoft server SW having problems with Microsoft's browser (which doesn't surprise me at all). Unfortunately, I don't have much control over the IIS configuration that will be hosting the app. Has anyone seen this and found a way to combat it? Particularly on ASP.Net apps with jQuery and jQuery-UI? UPDATE One other data point: on at least one of the pages, just commenting out the jQuery-UI Datepicker component setup causes the problem to go away, but I don't think (or at least I'm not sure) if that fixes all of the pages. If it does "fix" them, I'll have to swap out plug-ins because that functionality needs to be there. There doesn't seem to be any open issues against jQuery-UI on IE6/7 currently... UPDATE 2 I checked the IIS settings and "enable content expiration" was not set on any of my folders. Unchecking that setting was a common suggestion for fixing this problem. I have another, simpler, page that I can consistently create the error on. I'm using the jQuery-UI 1.6rc6 file (although I've also tried jQuery-UI 1.7.1 with the same results). The problem only occurs when I refresh the page that contains the jQuery-UI Datepicker. If I comment out the Datepicker setup, the problem goes away. Here are a few things I notice when I do this: This page always says "(1 item remaining) Downloading picture http:///images/Calendar_scheduleHS.gif", but only when reloading. When I look at HTTP logging, I see that it requests that image from the server every time it is dynamically turned on, without regard to caching. All of the requests for that graphic are complete and return the graphic correctly. None are marked code 200 or 304 (indicating that the server is telling IE to use the cached version). Why it says waiting on that graphic when all of the requests have completed I have no idea. There is a single other graphic on the page (one of the UI PNG files) that has a code 304 (Not Modified). On another page where I managed to log HTTP traffic with "2 items remaining", two different graphic files (both UI PNGs) had a 304 as well (but neither was the one listed as "Downloading". This error is not innocuous - the page is not fully responsive. For example, if I click on one of the buttons which should execute a client-side action, the page refreshes. Going away from the page and coming back does not produce the error. I have moved the script and script references to the bottom of the content and this doesn't affect this problem. The script is still running in the $(document).ready() though (it's too hairy to divide out unless I absolutely have to). FINAL UPDATE AND ANSWER There were a lot of good answers and suggestions below, but none of them were exactly our problem. The closest one (and the one that led me to the solution) was the one about long running JavaScript, so I awarded the bounty there (I guess I could have answered it myself, but I'd rather reward info that leads to solutions). Here was our solution: We had multiple jQueryUI datepickers that were created on the $(document).ready event in script included from the ASP.Net master page. On this client page, a local script's $(document).ready event had script that destroyed the datepickers under certain conditions. We had to use "destroy" because the previous version of datepicker had a problem with "disable". When we upgraded to the latest version of jQuery UI (1.7.1) and replaced the "destroy"s with "disable"s for the datepickers, the problem went away (or mostly went away - if you do things too fast while the page is loading, it is still possible to get the "n items remaining" status). My theory as to what was happening goes like this: The page content loads and has 12 or so text boxes with the datepicker class. The master page script creates datepickers on those text boxes. IE queues up requests for each calendar graphic independently because IE doesn't know how to properly cache dynamic image requests. Before the requests get processed, the client area script destroys those datepickers so the graphics are no longer needed. IE is left with some number of orphaned requests that it doesn't know what to do with.

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  • Eventlet or gevent or Stackless + Twisted, Pylons, Django and SQL Alchemy

    - by Khorkrak
    We're using Twisted extensively for apps requiring a great deal of asynchronous io. There are some cases where stuff is cpu bound instead and for that we spawn a pool of processes to do the work and have a system for managing these across multiple servers as well - all done in Twisted. Works great. The problem is that it's hard to bring new team members up to speed. Writing asynchronous code in Twisted requires a near vertical learning curve. It's as if humans just don't think that way naturally. We're considering a mixed approach perhaps. Maybe do the xmlrpc server part and process management in Twisted still but the other stuff in code that at least looks synchronous while not being as such. Then again I like explicit over implicit so hmmm. Anyway onto greenlets - how well does that stuff work? So there's Stackless and as you can see from my Gallentean avatar I'm well aware of the tremendous success in it's use for CCP's flagship EVE Online game first hand. What about Eventlet or gevent? Well for now only Eventlet works with Twisted. However gevent claims to be faster since it's not a pure python implementation it instead uses libevent. It also has fewer idiosyncrasies and defects supposedly. The documentation there is minimal in comparison to Eventlet and it's maintained by 1 guy as far as I can tell. This makes me leery but all great projects start this way so... Then there's PyPy - I haven't even finished reading about that one yet - just saw it in this thread: Drawbacks of Stackless. So confusing - I'm wondering what the heck to do - sounds like Eventlet is probably the best bet but is it really stable enough? Anyone out there have any experience with it? Should we go with Stackless instead as it's been around and is proven technology - just like Twisted is as well - and they do work together nicely. But still I hate having to have a separate version of Python to do this. what to do.... This somewhat obnoxious blog entry hit the nail on the head for me though: Asynchronous IO for Grownups We're stuck using MySQL as well - I never knew how great PostgreSQL was until having had to work on a production OLTP system in MySQL instead - but that's another story. But if that monkey patch thing really works then wow. Just wow.

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  • Fluid CSS: floating column with max-width and overflow

    - by Ates Goral
    I'm using a fluid layout in the new theme that I'm working on for my blog. I often blog about code and include <pre> blocks within the posts. The float: left column for the content area has a max-width so that the column stops at a certain maximum width and can also be shrunk: +----------+ +------+ | text | | text | | | | | | | | | | | | | | | | | | | | | +----------+ +------+ max shrunk What I want is for the <pre> elements to be wider than the text column so that I can fit 80-character-wrapped code without horizontal scroll bars. But I want the <pre> elements to overflow from the content area, without affecting its fluidity: +----------+ +------+ | text | | text | | | | | +----------+--+ +------+------+ | code | | code | +----------+--+ +------+------+ | | | | +----------+ +------+ max shrunk But, max-width stops being fluid once I insert the overhanging <pre> in there: the width of the column remains at the specified max-width even when I shrink the browser beyond that width. I've reproduced the issue with this bare-minimum scenario: <div style="float: left; max-width: 460px; border: 1px solid red"> <p>Lorem ipsum dolor sit amet, consectetur adipisicing elit</p> <pre style="max-width: 700px; border: 1px solid blue"> function foo() { // Lorem ipsum dolor sit amet, consectetur adipisicing elit } </pre> <p>Lorem ipsum dolor sit amet, consectetur adipisicing elit</p> </div> I noticed that doing either of the following brings back the fluidity: Remove the <pre> (doh...) Remove the float: left The workaround I'm currently using is to insert the <pre> elements into "breaks" in the post column, so that the widths of the post segments and the <pre> segments are managed mutually exclusively: +----------+ +------+ | text | | text | +----------+ +------+ +-------------+ +-------------+ | code | | code | +-------------+ +-------------+ +----------+ +------+ +----------+ +------+ max shrunk But this forces me to insert additional closing and opening <div> elements into the post markup which I'd rather keep semantically pristine. Admittedly, I don't have a full grasp of how the box model works with floats with overflowing content, so I don't understand why the combination of float: left on the container and the <pre> inside it cripple the max-width of the container. I'm observing the same problem on Firefox/Chrome/Safari/Opera. IE6 (the crazy one) seems happy all the time. This also doesn't seem dependent on quirks/standards mode. Update I've done further testing to observe that max-width seems to get ignored when the element has a float: left. I glanced at the W3C box model chapter but couldn't immediately see an explicit mention of this behaviour. Any pointers?

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  • delta-dictionary/dictionary with revision awareness in python?

    - by shabbychef
    I am looking to create a dictionary with 'roll-back' capabilities in python. The dictionary would start with a revision number of 0, and the revision would be bumped up only by explicit method call. I do not need to delete keys, only add and update key,value pairs, and then roll back. I will never need to 'roll forward', that is, when rolling the dictionary back, all the newer revisions can be discarded, and I can start re-reving up again. thus I want behaviour like: >>> rr = rev_dictionary() >>> rr.rev 0 >>> rr["a"] = 17 >>> rr[('b',23)] = 'foo' >>> rr["a"] 17 >>> rr.rev 0 >>> rr.roll_rev() >>> rr.rev 1 >>> rr["a"] 17 >>> rr["a"] = 0 >>> rr["a"] 0 >>> rr[('b',23)] 'foo' >>> rr.roll_to(0) >>> rr.rev 0 >>> rr["a"] 17 >>> rr.roll_to(1) Exception ... Just to be clear, the state associated with a revision is the state of the dictionary just prior to the roll_rev() method call. thus if I can alter the value associated with a key several times 'within' a revision, and only have the last one remembered. I would like a fairly memory-efficient implementation of this: the memory usage should be proportional to the deltas. Thus simply having a list of copies of the dictionary will not scale for my problem. One should assume the keys are in the tens of thousands, and the revisions are in the hundreds of thousands. We can assume the values are immutable, but need not be numeric. For the case where the values are e.g. integers, there is a fairly straightforward implementation (have a list of dictionaries of the numerical delta from revision to revision). I am not sure how to turn this into the general form. Maybe bootstrap the integer version and add on an array of values? all help appreciated.

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  • .Net Custom Configuration Section and Saving Changes within PropertyGrid

    - by Paul
    If I load the My.Settings object (app.config) into a PropertyGrid, I am able to edit the property inside the propertygrid and the change is automatically saved. PropertyGrid1.SelectedObject = My.Settings I want to do the same with a Custom Configuration Section. Following this code example (from here http://www.codeproject.com/KB/vb/SerializePropertyGrid.aspx), he is doing explicit serialization to disk when a "Save" button is pushed. Public Class Form1 'Load AppSettings Dim _appSettings As New AppSettings() Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click _appSettings = AppSettings.Load() ' Actually change the form size Me.Size = _appSettings.WindowSize PropertyGrid1.SelectedObject = _appSettings End Sub Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.Click _appSettings.Save() End Sub End Class In my code, my custom section Inherits from ConfigurationSection (see below) Question: Is there something built into ConfigurationSection class that does the autosave? If not, what is the best way to handle this, should it be in the PropertyGrid.PropertyValueChagned? (how does the My.Settings handle this internally?) Here is the example Custom Class that I am trying to get to auto-save and how I load into property grid. Dim config As System.Configuration.Configuration = _ ConfigurationManager.OpenExeConfiguration( _ ConfigurationUserLevel.None) PropertyGrid2.SelectedObject = config.GetSection("CustomSection") Public NotInheritable Class CustomSection Inherits ConfigurationSection ' The collection (property bag) that contains ' the section properties. Private Shared _Properties As ConfigurationPropertyCollection ' The FileName property. Private Shared _FileName As New ConfigurationProperty("fileName", GetType(String), "def.txt", ConfigurationPropertyOptions.IsRequired) ' The MasUsers property. Private Shared _MaxUsers _ As New ConfigurationProperty("maxUsers", _ GetType(Int32), 1000, _ ConfigurationPropertyOptions.None) ' The MaxIdleTime property. Private Shared _MaxIdleTime _ As New ConfigurationProperty("maxIdleTime", _ GetType(TimeSpan), TimeSpan.FromMinutes(5), _ ConfigurationPropertyOptions.IsRequired) ' CustomSection constructor. Public Sub New() _Properties = New ConfigurationPropertyCollection() _Properties.Add(_FileName) _Properties.Add(_MaxUsers) _Properties.Add(_MaxIdleTime) End Sub 'New ' This is a key customization. ' It returns the initialized property bag. Protected Overrides ReadOnly Property Properties() _ As ConfigurationPropertyCollection Get Return _Properties End Get End Property <StringValidator( _ InvalidCharacters:=" ~!@#$%^&*()[]{}/;'""|\", _ MinLength:=1, MaxLength:=60)> _ <EditorAttribute(GetType(System.Windows.Forms.Design.FileNameEditor), GetType(System.Drawing.Design.UITypeEditor))> _ Public Property FileName() As String Get Return CStr(Me("fileName")) End Get Set(ByVal value As String) Me("fileName") = value End Set End Property <LongValidator(MinValue:=1, _ MaxValue:=1000000, ExcludeRange:=False)> _ Public Property MaxUsers() As Int32 Get Return Fix(Me("maxUsers")) End Get Set(ByVal value As Int32) Me("maxUsers") = value End Set End Property <TimeSpanValidator(MinValueString:="0:0:30", _ MaxValueString:="5:00:0", ExcludeRange:=False)> _ Public Property MaxIdleTime() As TimeSpan Get Return CType(Me("maxIdleTime"), TimeSpan) End Get Set(ByVal value As TimeSpan) Me("maxIdleTime") = value End Set End Property End Class 'CustomSection

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  • Synchronized Enumerator in C#

    - by Dan Bryant
    I'm putting together a custom SynchronizedCollection<T> class so that I can have a synchronized Observable collection for my WPF application. The synchronization is provided via a ReaderWriterLockSlim, which, for the most part, has been easy to apply. The case I'm having trouble with is how to provide thread-safe enumeration of the collection. I've created a custom IEnumerator<T> nested class that looks like this: private class SynchronizedEnumerator : IEnumerator<T> { private SynchronizedCollection<T> _collection; private int _currentIndex; internal SynchronizedEnumerator(SynchronizedCollection<T> collection) { _collection = collection; _collection._lock.EnterReadLock(); _currentIndex = -1; } #region IEnumerator<T> Members public T Current { get; private set;} #endregion #region IDisposable Members public void Dispose() { var collection = _collection; if (collection != null) collection._lock.ExitReadLock(); _collection = null; } #endregion #region IEnumerator Members object System.Collections.IEnumerator.Current { get { return Current; } } public bool MoveNext() { var collection = _collection; if (collection == null) throw new ObjectDisposedException("SynchronizedEnumerator"); _currentIndex++; if (_currentIndex >= collection.Count) { Current = default(T); return false; } Current = collection[_currentIndex]; return true; } public void Reset() { if (_collection == null) throw new ObjectDisposedException("SynchronizedEnumerator"); _currentIndex = -1; Current = default(T); } #endregion } My concern, however, is that if the Enumerator is not Disposed, the lock will never be released. In most use cases, this is not a problem, as foreach should properly call Dispose. It could be a problem, however, if a consumer retrieves an explicit Enumerator instance. Is my only option to document the class with a caveat implementer reminding the consumer to call Dispose if using the Enumerator explicitly or is there a way to safely release the lock during finalization? I'm thinking not, since the finalizer doesn't even run on the same thread, but I was curious if there other ways to improve this.

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  • Using Artificial Intelligence (AI) to predict Stock Prices

    - by akaphenom
    Given a set of datavery similar to the Motley Fool CAPS system, where individual users enter BUY and SELL recommendations on various equities. What I would like to do is show each recommendation and I guess some how rate (1-5) as to whether it was good predictor<5 (ie corellation coeffient = 1) of the future stock price (or eps or whatever) or a horrible predictor (ie corellation coeffient = -1) or somewhere inbetween. Each recommendation is tagged to a particular user, so that can be tracked over time. I can also track market direction (bullish / bearish) based off of something like sp500 price. The components I think that would make sense in the model would be: user direction (long/short) market direction sector of stock The thought is that some users are better in bull markets than bear (and vice versa), and some are better at shorts than longs- and then a cobination the above. I can automatically tag the market direction and sector (based off the market at the time and the equity being recommended). The thought is that I could present a series of screens and allow me to rank each individual recommendation by displaying available data absolute, market and sector out performance for a specfic time period out. I would follow a detailed list for ranking the stocks so that the ranking is as objective as possible. My assumtion is that a single user is right no more than 57% of the time - but who knows. I could load the system and say "Lets rank the recommendation as a predictor of stock value 90 days forward"; and that would represent a very explicit set of rankings. NOW here is the crux - I want to create some sort of machine learning algorithm that can identify patterns over a series of time so that as recommendations stream into the application we maintain a ranking of that stock (ie. similar to correlation coeeficient) as to the likelihood of that recommendation (in addition to the past series of recommendations ) will affect the price. Now here is the super crux. I have never taken an AI class / read an AI book / never mind specific to machine learning. So I cam looking for guidance - sample or description of a similar system I could adapt. Place to look for info or any general help. Or even push me in the right direction to get started... My hope is to implment this with F# and be able to impress my friends with a new skillset in F# with an implementation of machine learnign and potentially something (application / source) I can include in a tech portfolio or blog space; Thank you for any advice in advance.

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  • VBScript Out of String space

    - by MalsiaPro
    I got the following code to capture information for files on a specified drive, I ran the script againts a 600 GB hard drive on one of our servers and after a while I get the error Out of String space; "Join". Line 34, Char 2 For this code, file script.vbs: Option Explicit Dim objFS, objFld Dim objArgs Dim strFolder, strDestFile, blnRecursiveSearch ''Dim strLines Dim strCsv ''Dim i '' i = 0 ' 'Get the commandline parameters ' Set objArgs = WScript.Arguments ' strFolder = objArgs(0) ' strDestFile = objArgs(1) ' blnRecursiveSearch = objArgs(2) '######################################## 'SPECIFY THE DRIVE YOU WANT TO SCAN BELOW '######################################## strFolder = "C:\" strDestFile = "C:\InformationOutput.csv" blnRecursiveSearch = True 'Create the FileSystemObject Set objFS=CreateObject("Scripting.FileSystemObject") 'Get the directory you are working in Set objFld = objFS.GetFolder(strFolder) 'Open the csv file Set strCsv = objFS.CreateTextFile(strDestFile, True) '' 'Write the csv file '' Set strCsv = objFS.CreateTextFile(strDestFile, True) strCsv.WriteLine "File Path,File Size,Date Created,Date Last Modified,Date Last Accessed" '' strCsv.Write Join(strLines, vbCrLf) 'Now get the file details GetFileDetails objFld, blnRecursiveSearch '' 'Close and cleanup objects '' strCsv.Close '' 'Write the csv file '' Set strCsv = objFS.CreateTextFile(strDestFile, True) '' For i = 0 to UBound(strLines) '' strCsv.WriteLine strLines(i) '' Next 'Close and cleanup objects strCsv.Close Set strCsv = Nothing Set objFld = Nothing Set strFolder = Nothing Set objArgs = Nothing '---------------------------SCAN SPECIFIED LOCATION------------------------------- Private Sub GetFileDetails(fold, blnRecursive) Dim fld, fil dim strLine(4) on error resume next If InStr(fold.Path, "System Volume Information") < 1 Then If blnRecursive Then 'Work through all the folders and subfolders For Each fld In fold.SubFolders GetFileDetails fld, True If err.number <> 0 then LogError err.Description & vbcrlf & "Folder - " & fold.Path err.Clear End If Next End If 'Now work on the files For Each fil in fold.Files strLine(0) = fil.Path strLine(1) = fil.Size strLine(2) = fil.DateCreated strLine(3) = fil.DateLastModified strLine(4) = fil.DateLastAccessed strCsv.WriteLine Join(strLine, ",") if err.number <> 0 then LogError err.Description & vbcrlf & "Folder - " & fold.Path & vbcrlf & "File - " & fil.Name err.Clear End If Next End If end sub Private sub LogError(strError) dim strErr 'Write the csv file Set strErr = objFS.CreateTextFile("C:\test\err.log", false) strErr.WriteLine strError strErr.Close Set strErr = nothing End Sub RunMe.cmd wscript.exe "C:\temp\script\script.vbs" How can I avoid getting this error? The server drives are quite a bit <???? and I would imagine that the CSV file would be at least 40 MB. Edit by Guffa: I commented out some lines in the code, using double ticks ('') so you can see where.

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  • Guides for PostgreSQL query tuning?

    - by Joe
    I've found a number of resources that talk about tuning the database server, but I haven't found much on the tuning of the individual queries. For instance, in Oracle, I might try adding hints to ignore indexes or to use sort-merge vs. correlated joins, but I can't find much on tuning Postgres other than using explicit joins and recommendations when bulk loading tables. Do any such guides exist so I can focus on tuning the most run and/or underperforming queries, hopefully without adversely affecting the currently well-performing queries? I'd even be happy to find something that compared how certain types of queries performed relative to other databases, so I had a better clue of what sort of things to avoid. update: I should've mentioned, I took all of the Oracle DBA classes along with their data modeling and SQL tuning classes back in the 8i days ... so I know about 'EXPLAIN', but that's more to tell you what's going wrong with the query, not necessarily how to make it better. (eg, are 'while var=1 or var=2' and 'while var in (1,2)' considered the same when generating an execution plan? What if I'm doing it with 10 permutations? When are multi-column indexes used? Are there ways to get the planner to optimize for fastest start vs. fastest finish? What sort of 'gotchas' might I run into when moving from mySQL, Oracle or some other RDBMS?) I could write any complex query dozens if not hundreds of ways, and I'm hoping to not have to try them all and find which one works best through trial and error. I've already found that 'SELECT count(*)' won't use an index, but 'SELECT count(primary_key)' will ... maybe a 'PostgreSQL for experienced SQL users' sort of document that explained sorts of queries to avoid, and how best to re-write them, or how to get the planner to handle them better. update 2: I found a Comparison of different SQL Implementations which covers PostgreSQL, DB2, MS-SQL, mySQL, Oracle and Informix, and explains if, how, and gotchas on things you might try to do, and his references section linked to Oracle / SQL Server / DB2 / Mckoi /MySQL Database Equivalents (which is what its title suggests) and to the wikibook SQL Dialects Reference which covers whatever people contribute (includes some DB2, SQLite, mySQL, PostgreSQL, Firebird, Vituoso, Oracle, MS-SQL, Ingres, and Linter).

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  • How can we implement change notification propagation for WPF and SL in the MVVM pattern?

    - by Firoso
    Here's an example scenario targetting MVVM WPF/SL development: View data binds to view model Property "Target" "Target" exposes a field of an object called "data" that exists in the local application model, called "Original" when "Original" changes, it should raise notification to the view model and then propogate that change notification to the View. Here are the solutions I've come up with, but I don't like any of them all that much. I'm looking for other ideas, by the time we come up with something rock solid I'm certain Microsoft will have released .NET 5 with WPF/SL extensions for better tools for MVVM development. For now the question is, "What have you done to solve this problem and how has it worked out for you?" Option 1. Proposal: Attach a handler to data's PropertyChanged event that watches for string values of properties it cares about that might have changed, and raises the appropriate notification. Why I don't like it: Changes don't bubble naturally, objects must be explicitly watched, if data changes to a new source, events must be un-registered/registered. Why I kind of like it: I get explicit control over propogation of changes, and I don't have to use any types that belong at a higher level of the application such as dependancy properties. Option 2. Proposal: Attach a handler to data's PropertyChanged event that re-raises the event across all properties using the name property name. Why I don't like it: This is essentially the same as option 1, but less intelligent, and forces me to never change my property names, as they have to be the same as the property names on data Why I kind of like it: It's very easy to set up and I don't have to think about it... Then again if I try to think, and change names to things that make sense, I shoot myself in the foot, and then I have to think about it! Option 3. Proposal: Inherit my view model from dependancy object, and notify binding sources of changes directly. Why I don't like it: I'm not even 100% sure dependancy properties/objects can DO this, it was just a thought to look into. Also I don't personally feel that WPF/SL types like Dep Obj belong at the view model level. Why I kind of like it: IF it has the capability that I'm seeking then it's a good answer! minus that pesky layering issue. Option 4. Proposal: Use a consistant agent messaging system based off of Task Parallels DataFlow Library to propogate everything through linked pipelining. Why I don't like it: I've never tried this, and somehow I think it will be lacking, plus it requires me to think about my code completely differently all the way around. Why I kind of like it: It has the possiblity of allowing me to do some VERY fun manipulations with a push based data model and using ActionBlocks as validation AND setters to then privately change view model properties and explicitly control PropertyChanged notifications.

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  • How to optimize Core Data query for full text search

    - by dk
    Can I optimize a Core Data query when searching for matching words in a text? (This question also pertains to the wisdom of custom SQL versus Core Data on an iPhone.) I'm working on a new (iPhone) app that is a handheld reference tool for a scientific database. The main interface is a standard searchable table view and I want as-you-type response as the user types new words. Words matches must be prefixes of words in the text. The text is composed of 100,000s of words. In my prototype I coded SQL directly. I created a separate "words" table containing every word in the text fields of the main entity. I indexed words and performed searches along the lines of SELECT id, * FROM textTable JOIN (SELECT DISTINCT textTableId FROM words WHERE word BETWEEN 'foo' AND 'fooz' ) ON id=textTableId LIMIT 50 This runs very fast. Using an IN would probably work just as well, i.e. SELECT * FROM textTable WHERE id IN (SELECT textTableId FROM words WHERE word BETWEEN 'foo' AND 'fooz' ) LIMIT 50 The LIMIT is crucial and allows me to display results quickly. I notify the user that there are too many to display if the limit is reached. This is kludgy. I've spent the last several days pondering the advantages of moving to Core Data, but I worry about the lack of control in the schema, indexing, and querying for an important query. Theoretically an NSPredicate of textField MATCHES '.*\bfoo.*' would just work, but I'm sure it will be slow. This sort of text search seems so common that I wonder what is the usual attack? Would you create a words entity as I did above and use a predicate of "word BEGINSWITH 'foo'"? Will that work as fast as my prototype? Will Core Data automatically create the right indexes? I can't find any explicit means of advising the persistent store about indexes. I see some nice advantages of Core Data in my iPhone app. The faulting and other memory considerations allow for efficient database retrievals for tableview queries without setting arbitrary limits. The object graph management allows me to easily traverse entities without writing lots of SQL. Migration features will be nice in the future. On the other hand, in a limited resource environment (iPhone) I worry that an automatically generated database will be bloated with metadata, unnecessary inverse relationships, inefficient attribute datatypes, etc. Should I dive in or proceed with caution?

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  • .NET: understanding web.config in asp.net

    - by mark smith
    Hi there, Does anyone know of a good link to explain how to use the web.config...... For example, i am using forms authentication... and i notice there is a system.web and then it closed /system.web and then below configuration there are additional location tags here is an example, if you ntoice there is an authentication mode=forms with authorization i presume this is the ROOT....... It is also self contained within a system.web .... Below this there are more location= with system.web tags.... I have never really understand what i am actually doing.. I have tried checkign the MSDN documentation but still i don't fully understand up.... Can anyone help? If you notice with my example.... everything is stored in 1 web.config... i thought the standard waas create a standard web.config and then create another web.config in the directory where i wish to protect it..??? <configuration> <system.web> <compilation debug="true" strict="false" explicit="true" targetFramework="4.0" /> <authentication mode="Forms"> <forms loginUrl="Login.aspx" defaultUrl="Login.aspx" cookieless="UseCookies" timeout="60"/> </authentication> <authorization> <allow users="*"/> </authorization> </system.web> <location path="Forms"> <system.web> <authorization> <deny users="?"/> <allow users="*"/> </authorization> </system.web> </location> <location path="Forms/Seguridad"> <system.web> <authorization> <allow roles="Administrador"/> <deny users="?"/> </authorization> </system.web> </location>

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  • Challenge: Neater way of currying or partially applying C#4's string.Join

    - by Damian Powell
    Background I recently read that .NET 4's System.String class has a new overload of the Join method. This new overload takes a separator, and an IEnumerable<T> which allows arbitrary collections to be joined into a single string without the need to convert to an intermediate string array. Cool! That means I can now do this: var evenNums = Enumerable.Range(1, 100) .Where(i => i%2 == 0); var list = string.Join(",",evenNums); ...instead of this: var evenNums = Enumerable.Range(1, 100) .Where(i => i%2 == 0) .Select(i => i.ToString()) .ToArray(); var list = string.Join(",", evenNums); ...thus saving on a conversion of every item to a string, and then the allocation of an array. The Problem However, being a fan of the functional style of programming in general, and method chaining in C# in particular, I would prefer to be able to write something like this: var list = Enumerable.Range(1, 100) .Where(i => i%2 == 0) .string.Join(","); This is not legal C# though. The closest I've managed to get is this: var list = Enumerable.Range(1, 100) .Where(i => i%2 == 0) .ApplyTo( Functional.Curry<string, IEnumerable<object>, string> (string.Join)(",") ); ...using the following extension methods: public static class Functional { public static TRslt ApplyTo<TArg, TRslt>(this TArg arg, Func<TArg, TRslt> func) { return func(arg); } public static Func<T1, Func<T2, TResult>> Curry<T1, T2, TResult>(this Func<T1, T2, TResult> func) { Func<Func<T1, T2, TResult>, Func<T1, Func<T2, TResult>>> curried = f => x => y => f(x, y); return curried(func); } } This is quite verbose, requires explicit definition of the parameters and return type of the string.Join overload I want to use, and relies upon C#4's variance features because we are defining one of the arguments as IEnumerable rather than IEnumerable. The Challenge Can you find a neater way of achieving this using the method-chaining style of programming?

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  • Synchronized IEnumerator<T>

    - by Dan Bryant
    I'm putting together a custom SynchronizedCollection<T> class so that I can have a synchronized Observable collection for my WPF application. The synchronization is provided via a ReaderWriterLockSlim, which, for the most part, has been easy to apply. The case I'm having trouble with is how to provide thread-safe enumeration of the collection. I've created a custom IEnumerator<T> nested class that looks like this: private class SynchronizedEnumerator : IEnumerator<T> { private SynchronizedCollection<T> _collection; private int _currentIndex; internal SynchronizedEnumerator(SynchronizedCollection<T> collection) { _collection = collection; _collection._lock.EnterReadLock(); _currentIndex = -1; } #region IEnumerator<T> Members public T Current { get; private set;} #endregion #region IDisposable Members public void Dispose() { var collection = _collection; if (collection != null) collection._lock.ExitReadLock(); _collection = null; } #endregion #region IEnumerator Members object System.Collections.IEnumerator.Current { get { return Current; } } public bool MoveNext() { var collection = _collection; if (collection == null) throw new ObjectDisposedException("SynchronizedEnumerator"); _currentIndex++; if (_currentIndex >= collection.Count) { Current = default(T); return false; } Current = collection[_currentIndex]; return true; } public void Reset() { if (_collection == null) throw new ObjectDisposedException("SynchronizedEnumerator"); _currentIndex = -1; Current = default(T); } #endregion } My concern, however, is that if the Enumerator is not Disposed, the lock will never be released. In most use cases, this is not a problem, as foreach should properly call Dispose. It could be a problem, however, if a consumer retrieves an explicit Enumerator instance. Is my only option to document the class with a caveat implementer reminding the consumer to call Dispose if using the Enumerator explicitly or is there a way to safely release the lock during finalization? I'm thinking not, since the finalizer doesn't even run on the same thread, but I was curious if there other ways to improve this. EDIT After thinking about this a bit and reading the responses (particular thanks to Hans), I've decided this is definitely a bad idea. The biggest issue actually isn't forgetting to Dispose, but rather a leisurely consumer creating deadlock while enumerating. I now only read-lock long enough to get a copy and return the enumerator for the copy.

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  • CSS text-decoration rule ignored

    - by Ferdy
    I have found similar questions to mine but none of the suggestions seems to apply to my situation, so here goes... I have a webpage with a buch of images on them. Each image has a title which in markup is between h2 tags. The title is a link, so the resulting markup is like this: <ul class="imagelist"> <li> <a href=""><h2>Title 1</h2></a> <a href=""><img src="" /></a> </li> <li> Image 2, etc... </li> </ul> All I want is for the title links to not be underlined. I tried to address this like this: .imagelist li a h2 { color:#333; text-decoration:none; } It completely ignores the text-decoration rule, yet respects the color rule. From other questions I learned that this could be because a child element cannot overrule the text-decoration of any of its parents. So, I went looking for the parent elements to see if any explicit text-decoration rules are applied. I found none. This is driving me crazy, any help? For the sake of completeness, here is the Firebug CSS output, which shows the full inheritance and such. Probably more than you want, but I cannot see anything conflicting here. .imagelist li a h2 { color:#333333; text-decoration:none; } main.css (line 417) h2 { font-size:14px; } main.css (line 40) h1, h2, h3, h4, h5, h6 { display:block; font-weight:bold; margin-bottom:10px; } main.css (line 38) h1, h2, h3, h4, h5, h6 { font-size:100%; font-weight:normal; } reset-min.css (line 7) body, div, dl, dt, dd, ul, ol, li, h1, h2, h3, h4, h5, h6, pre, code, form, fieldset, legend, input, textarea, p, blockquote, th, td { margin:0; padding:0; } reset-min.css (line 7) Inherited froma /apps/ju...mage/745 a { color:#0063E2; } main.css (line 55) Inherited fromli .imagelist li { list-style-type:none; } main.css (line 411) li { list-style:none outside none; } reset-min.css (line 7) Inherited fromul.imagelist .imagelist { border-collapse:collapse; font-size:9px; } main.css (line 410) Inherited frombody body, form { color:#333333; font:12px arial,helvetica,clean,sans-serif; } main.css (line 36) Inherited fromhtml html { color:#000000;

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  • Why does Android Account & Sync reboot when trying to find my settings activity?

    - by mobibob
    I have an activity that I can declare as Launcher category and it launches just fine from the home screen. However, when I try to hook-up the same activity into my SyncAdapter's settings activity and open it from the Accounts & Sync page - MySyncAdapter - (touch account listing) it aborts with a system fatal error (reboots phone). Meanwhile, my SyncAdapter is working other respects. Here is the log at point of impact: 01-13 12:31:00.976 5024 5038 I ActivityManager: Starting activity: Intent { act=android.provider.Settings.ACTION_SYNC_SETTINGS flg=0x10000000 cmp=com.myapp.android.syncadapter.ui/SyncAdapterSettingsActivity.class (has extras) } 01-13 12:31:00.985 5024 5038 E AndroidRuntime: *** FATAL EXCEPTION IN SYSTEM PROCESS: android.server.ServerThread 01-13 12:31:00.985 5024 5038 E AndroidRuntime: android.content.ActivityNotFoundException: Unable to find explicit activity class {com.myapp.android.syncadapter.ui/SyncAdapterSettingsActivity.class}; have you declared this activity in your AndroidManifest.xml? 01-13 12:31:00.985 5024 5038 E AndroidRuntime: at android.app.Instrumentation.checkStartActivityResult(Instrumentation.java:1404) 01-13 12:31:00.985 5024 5038 E AndroidRuntime: at android.app.Instrumentation.execStartActivity(Instrumentation.java:1378) 01-13 12:31:00.985 5024 5038 E AndroidRuntime: at android.app.ContextImpl.startActivity(ContextImpl.java:622) 01-13 12:31:00.985 5024 5038 E AndroidRuntime: at android.preference.Preference.performClick(Preference.java:828) 01-13 12:31:00.985 5024 5038 E AndroidRuntime: at android.preference.PreferenceScreen.onItemClick(PreferenceScreen.java:190) 01-13 12:31:00.985 5024 5038 E AndroidRuntime: at android.widget.AdapterView.performItemClick(AdapterView.java:284) 01-13 12:31:00.985 5024 5038 E AndroidRuntime: at android.widget.ListView.performItemClick(ListView.java:3382) 01-13 12:31:00.985 5024 5038 E AndroidRuntime: at android.widget.AbsListView$PerformClick.run(AbsListView.java:1696) 01-13 12:31:00.985 5024 5038 E AndroidRuntime: at android.os.Handler.handleCallback(Handler.java:587) 01-13 12:31:00.985 5024 5038 E AndroidRuntime: at android.os.Handler.dispatchMessage(Handler.java:92) 01-13 12:31:00.985 5024 5038 E AndroidRuntime: at android.os.Looper.loop(Looper.java:123) 01-13 12:31:00.985 5024 5038 E AndroidRuntime: at com.android.server.ServerThread.run(SystemServer.java:517) 01-13 12:31:00.985 5024 5038 I Process : Sending signal. PID: 5024 SIG: 9 01-13 12:31:01.005 5019 5019 I Zygote : Exit zygote because system server (5024) has terminated 01-13 12:31:01.015 1211 1211 E installd: eof Here is a snippet from my manifest file: <activity android:name="com.myapp.android.syncadapter.ui.SyncAdapterSettingsActivity" android:label="@string/title_settings" android:windowSoftInputMode="stateAlwaysHidden|adjustPan"> <intent-filter> <action android:name="android.intent.action.VIEW" /> <action android:name="android.intent.action.MAIN" /> <action android:name="android.provider.Settings.ACTION_SYNC_SETTINGS"/> <category android:name="android.intent.category.DEFAULT" /> <category android:name="android.intent.category.LAUNCHER" /> </intent-filter> </activity>

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