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  • How to create a new WCF/MVC/jQuery application from scratch

    - by pjohnson
    As a corporate developer by trade, I don't get much opportunity to create from-the-ground-up web sites; usually it's tweaks, fixes, and new functionality to existing sites. And with hobby sites, I often don't find the challenges I run into with enterprise systems; usually it's starting from Visual Studio's boilerplate project and adding whatever functionality I want to play around with, rarely deploying outside my own machine. So my experience creating a new enterprise-level site was a bit dated, and the technologies to do so have come a long way, and are much more ready to go out of the box. My intention with this post isn't so much to provide any groundbreaking insights, but to just tie together a lot of information in one place to make it easy to create a new site from scratch. Architecture One site I created earlier this year had an MVC 3 front end and a WCF 4-driven service layer. Using Visual Studio 2010, these project types are easy enough to add to a new solution. I created a third Class Library project to store common functionality the front end and services layers both needed to access, for example, the DataContract classes that the front end uses to call services in the service layer. By keeping DataContract classes in a separate project, I avoided the need for the front end to have an assembly/project reference directly to the services code, a bit cleaner and more flexible of an SOA implementation. Consuming the service Even by this point, VS has given you a lot. You have a working web site and a working service, neither of which do much but are great starting points. To wire up the front end and the services, I needed to create proxy classes and WCF client configuration information. I decided to use the SvcUtil.exe utility provided as part of the Windows SDK, which you should have installed if you installed VS. VS also provides an Add Service Reference command since the .NET 1.x ASMX days, which I've never really liked; it creates several .cs/.disco/etc. files, some of which contained hardcoded URL's, adding duplicate files (*1.cs, *2.cs, etc.) without doing a good job of cleaning up after itself. I've found SvcUtil much cleaner, as it outputs one C# file (containing several proxy classes) and a config file with settings, and it's easier to use to regenerate the proxy classes when the service changes, and to then maintain all your configuration in one place (your Web.config, instead of the Service Reference files). I provided it a reference to a copy of my common assembly so it doesn't try to recreate the data contract classes, had it use the type List<T> for collections, and modified the output files' names and .NET namespace, ending up with a command like: svcutil.exe /l:cs /o:MyService.cs /config:MyService.config /r:MySite.Common.dll /ct:System.Collections.Generic.List`1 /n:*,MySite.Web.ServiceProxies http://localhost:59999/MyService.svc I took the generated MyService.cs file and drop it in the web project, under a ServiceProxies folder, matching the namespace and keeping it separate from classes I coded manually. Integrating the config file took a little more work, but only needed to be done once as these settings didn't often change. A great thing Microsoft improved with WCF 4 is configuration; namely, you can use all the default settings and not have to specify them explicitly in your config file. Unfortunately, SvcUtil doesn't generate its config file this way. If you just copy & paste MyService.config's contents into your front end's Web.config, you'll copy a lot of settings you don't need, plus this will get unwieldy if you add more services in the future, each with its own custom binding. Really, as the only mandatory settings are the endpoint's ABC's (address, binding, and contract) you can get away with just this: <system.serviceModel>  <client>    <endpoint address="http://localhost:59999/MyService.svc" binding="wsHttpBinding" contract="MySite.Web.ServiceProxies.IMyService" />  </client></system.serviceModel> By default, the services project uses basicHttpBinding. As you can see, I switched it to wsHttpBinding, a more modern standard. Using something like netTcpBinding would probably be faster and more efficient since the client & service are both written in .NET, but it requires additional server setup and open ports, whereas switching to wsHttpBinding is much simpler. From an MVC controller action method, I instantiated the client, and invoked the method for my operation. As with any object that implements IDisposable, I wrapped it in C#'s using() statement, a tidy construct that ensures Dispose gets called no matter what, even if an exception occurs. Unfortunately there are problems with that, as WCF's ClientBase<TChannel> class doesn't implement Dispose according to Microsoft's own usage guidelines. I took an approach similar to Technology Toolbox's fix, except using partial classes instead of a wrapper class to extend the SvcUtil-generated proxy, making the fix more seamless from the controller's perspective, and theoretically, less code I have to change if and when Microsoft fixes this behavior. User interface The MVC 3 project template includes jQuery and some other common JavaScript libraries by default. I updated the ones I used to the latest versions using NuGet, available in VS via the Tools > Library Package Manager > Manage NuGet Packages for Solution... > Updates. I also used this dialog to remove packages I wasn't using. Given that it's smart enough to know the difference between the .js and .min.js files, I was hoping it would be smart enough to know which to include during build and publish operations, but this doesn't seem to be the case. I ended up using Cassette to perform the minification and bundling of my JavaScript and CSS files; ASP.NET 4.5 includes this functionality out of the box. The web client to web server link via jQuery was easy enough. In my JavaScript function, unobtrusively wired up to a button's click event, I called $.ajax, corresponding to an action method that returns a JsonResult, accomplished by passing my model class to the Controller.Json() method, which jQuery helpfully translates from JSON to a JavaScript object.$.ajax calls weren't perfectly straightforward. I tried using the simpler $.post method instead, but ran into trouble without specifying the contentType parameter, which $.post doesn't have. The url parameter is simple enough, though for flexibility in how the site is deployed, I used MVC's Url.Action method to get the URL, then sent this to JavaScript in a JavaScript string variable. If the request needed input data, I used the JSON.stringify function to convert a JavaScript object with the parameters into a JSON string, which MVC then parses into strongly-typed C# parameters. I also specified "json" for dataType, and "application/json; charset=utf-8" for contentType. For success and error, I provided my success and error handling functions, though success is a bit hairier. "Success" in this context indicates whether the HTTP request succeeds, not whether what you wanted the AJAX call to do on the web server was successful. For example, if you make an AJAX call to retrieve a piece of data, the success handler will be invoked for any 200 OK response, and the error handler will be invoked for failed requests, e.g. a 404 Not Found (if the server rejected the URL you provided in the url parameter) or 500 Internal Server Error (e.g. if your C# code threw an exception that wasn't caught). If an exception was caught and handled, or if the data requested wasn't found, this would likely go through the success handler, which would need to do further examination to verify it did in fact get back the data for which it asked. I discuss this more in the next section. Logging and exception handling At this point, I had a working application. If I ran into any errors or unexpected behavior, debugging was easy enough, but of course that's not an option on public web servers. Microsoft Enterprise Library 5.0 filled this gap nicely, with its Logging and Exception Handling functionality. First I installed Enterprise Library; NuGet as outlined above is probably the best way to do so. I needed a total of three assembly references--Microsoft.Practices.EnterpriseLibrary.ExceptionHandling, Microsoft.Practices.EnterpriseLibrary.ExceptionHandling.Logging, and Microsoft.Practices.EnterpriseLibrary.Logging. VS links with the handy Enterprise Library 5.0 Configuration Console, accessible by right-clicking your Web.config and choosing Edit Enterprise Library V5 Configuration. In this console, under Logging Settings, I set up a Rolling Flat File Trace Listener to write to log files but not let them get too large, using a Text Formatter with a simpler template than that provided by default. Logging to a different (or additional) destination is easy enough, but a flat file suited my needs. At this point, I verified it wrote as expected by calling the Microsoft.Practices.EnterpriseLibrary.Logging.Logger.Write method from my C# code. With those settings verified, I went on to wire up Exception Handling with Logging. Back in the EntLib Configuration Console, under Exception Handling, I used a LoggingExceptionHandler, setting its Logging Category to the category I already had configured in the Logging Settings. Then, from code (e.g. a controller's OnException method, or any action method's catch block), I called the Microsoft.Practices.EnterpriseLibrary.ExceptionHandling.ExceptionPolicy.HandleException method, providing the exception and the exception policy name I had configured in the Exception Handling Settings. Before I got this configured correctly, when I tried it out, nothing was logged. In working with .NET, I'm used to seeing an exception if something doesn't work or isn't set up correctly, but instead working with these EntLib modules reminds me more of JavaScript (before the "use strict" v5 days)--it just does nothing and leaves you to figure out why, I presume due in part to the listener pattern Microsoft followed with the Enterprise Library. First, I verified logging worked on its own. Then, verifying/correcting where each piece wires up to the next resolved my problem. Your C# code calls into the Exception Handling module, referencing the policy you pass the HandleException method; that policy's configuration contains a LoggingExceptionHandler that references a logCategory; that logCategory should be added in the loggingConfiguration's categorySources section; that category references a listener; that listener should be added in the loggingConfiguration's listeners section, which specifies the name of the log file. One final note on error handling, as the proper way to handle WCF and MVC errors is a whole other very lengthy discussion. For AJAX calls to MVC action methods, depending on your configuration, an exception thrown here will result in ASP.NET'S Yellow Screen Of Death being sent back as a response, which is at best unnecessarily and uselessly verbose, and at worst a security risk as the internals of your application are exposed to potential hackers. I mitigated this by overriding my controller's OnException method, passing the exception off to the Exception Handling module as above. I created an ErrorModel class with as few properties as possible (e.g. an Error string), sending as little information to the client as possible, to both maximize bandwidth and mitigate risk. I then return an ErrorModel in JSON format for AJAX requests: if (filterContext.HttpContext.Request.IsAjaxRequest()){    filterContext.Result = Json(new ErrorModel(...));    filterContext.ExceptionHandled = true;} My $.ajax calls from the browser get a valid 200 OK response and go into the success handler. Before assuming everything is OK, I check if it's an ErrorModel or a model containing what I requested. If it's an ErrorModel, or null, I pass it to my error handler. If the client needs to handle different errors differently, ErrorModel can contain a flag, error code, string, etc. to differentiate, but again, sending as little information back as possible is ideal. Summary As any experienced ASP.NET developer knows, this is a far cry from where ASP.NET started when I began working with it 11 years ago. WCF services are far more powerful than ASMX ones, MVC is in many ways cleaner and certainly more unit test-friendly than Web Forms (if you don't consider the code/markup commingling you're doing again), the Enterprise Library makes error handling and logging almost entirely configuration-driven, AJAX makes a responsive UI more feasible, and jQuery makes JavaScript coding much less painful. It doesn't take much work to get a functional, maintainable, flexible application, though having it actually do something useful is a whole other matter.

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  • Java Animation Memory Overload [on hold]

    - by user2425429
    I need a way to reduce the memory usage of these programs while keeping the functionality. Every time I add 50 milliseconds or so to the set&display loop in AnimationTest1, it throws an out of memory error. Here is the code I have now: import java.awt.DisplayMode; import java.awt.Graphics; import java.awt.Graphics2D; import java.awt.Image; import java.awt.Polygon; import java.util.ArrayList; import java.util.List; import java.util.concurrent.Executor; import java.util.concurrent.Executors; import javax.swing.ImageIcon; public class AnimationTest1 { public static void main(String args[]) { AnimationTest1 test = new AnimationTest1(); test.run(); } private static final DisplayMode POSSIBLE_MODES[] = { new DisplayMode(800, 600, 32, 0), new DisplayMode(800, 600, 24, 0), new DisplayMode(800, 600, 16, 0), new DisplayMode(640, 480, 32, 0), new DisplayMode(640, 480, 24, 0), new DisplayMode(640, 480, 16, 0) }; private static final long DEMO_TIME = 4000; private ScreenManager screen; private Image bgImage; private Animation anim; public void loadImages() { // create animation List<Polygon> polygons=new ArrayList(); int[] x=new int[]{20,4,4,20,40,56,56,40}; int[] y=new int[]{20,32,40,44,44,40,32,20}; polygons.add(new Polygon(x,y,8)); anim = new Animation(); //# of frames long startTime = System.currentTimeMillis(); long currTimer = startTime; long elapsedTime = 0; boolean animated = false; Graphics2D g = screen.getGraphics(); int width=200; int height=200; //set&display loop while (currTimer - startTime < DEMO_TIME*2) { //draw the polygons if(!animated){ for(int j=0; j<polygons.size();j++){ for(int pos=0; pos<polygons.get(j).npoints; pos++){ polygons.get(j).xpoints[pos]+=1; } } anim.setNewPolyFrame(polygons , width , height , 64); } else{ // update animation anim.update(elapsedTime); draw(g); g.dispose(); screen.update(); try{ Thread.sleep(20); } catch(InterruptedException ie){} } if(currTimer - startTime == DEMO_TIME) animated=true; elapsedTime = System.currentTimeMillis() - currTimer; currTimer += elapsedTime; } } public void run() { screen = new ScreenManager(); try { DisplayMode displayMode = screen.findFirstCompatibleMode(POSSIBLE_MODES); screen.setFullScreen(displayMode); loadImages(); } finally { screen.restoreScreen(); } } public void draw(Graphics g) { // draw background g.drawImage(bgImage, 0, 0, null); // draw image g.drawImage(anim.getImage(), 0, 0, null); } } ScreenManager: import java.awt.Color; import java.awt.DisplayMode; import java.awt.Graphics; import java.awt.Graphics2D; import java.awt.GraphicsConfiguration; import java.awt.GraphicsDevice; import java.awt.GraphicsEnvironment; import java.awt.Toolkit; import java.awt.Window; import java.awt.event.KeyListener; import java.awt.event.MouseListener; import java.awt.image.BufferStrategy; import java.awt.image.BufferedImage; import javax.swing.JFrame; import javax.swing.JPanel; public class ScreenManager extends JPanel { private GraphicsDevice device; /** Creates a new ScreenManager object. */ public ScreenManager() { GraphicsEnvironment environment=GraphicsEnvironment.getLocalGraphicsEnvironment(); device = environment.getDefaultScreenDevice(); setBackground(Color.white); } /** Returns a list of compatible display modes for the default device on the system. */ public DisplayMode[] getCompatibleDisplayModes() { return device.getDisplayModes(); } /** Returns the first compatible mode in a list of modes. Returns null if no modes are compatible. */ public DisplayMode findFirstCompatibleMode( DisplayMode modes[]) { DisplayMode goodModes[] = device.getDisplayModes(); for (int i = 0; i < modes.length; i++) { for (int j = 0; j < goodModes.length; j++) { if (displayModesMatch(modes[i], goodModes[j])) { return modes[i]; } } } return null; } /** Returns the current display mode. */ public DisplayMode getCurrentDisplayMode() { return device.getDisplayMode(); } /** Determines if two display modes "match". Two display modes match if they have the same resolution, bit depth, and refresh rate. The bit depth is ignored if one of the modes has a bit depth of DisplayMode.BIT_DEPTH_MULTI. Likewise, the refresh rate is ignored if one of the modes has a refresh rate of DisplayMode.REFRESH_RATE_UNKNOWN. */ public boolean displayModesMatch(DisplayMode mode1, DisplayMode mode2) { if (mode1.getWidth() != mode2.getWidth() || mode1.getHeight() != mode2.getHeight()) { return false; } if (mode1.getBitDepth() != DisplayMode.BIT_DEPTH_MULTI && mode2.getBitDepth() != DisplayMode.BIT_DEPTH_MULTI && mode1.getBitDepth() != mode2.getBitDepth()) { return false; } if (mode1.getRefreshRate() != DisplayMode.REFRESH_RATE_UNKNOWN && mode2.getRefreshRate() != DisplayMode.REFRESH_RATE_UNKNOWN && mode1.getRefreshRate() != mode2.getRefreshRate()) { return false; } return true; } /** Enters full screen mode and changes the display mode. If the specified display mode is null or not compatible with this device, or if the display mode cannot be changed on this system, the current display mode is used. <p> The display uses a BufferStrategy with 2 buffers. */ public void setFullScreen(DisplayMode displayMode) { JFrame frame = new JFrame(); frame.setUndecorated(true); frame.setIgnoreRepaint(true); frame.setResizable(true); device.setFullScreenWindow(frame); if (displayMode != null && device.isDisplayChangeSupported()) { try { device.setDisplayMode(displayMode); } catch (IllegalArgumentException ex) { } } frame.createBufferStrategy(2); Graphics g=frame.getGraphics(); g.setColor(Color.white); g.drawRect(0, 0, frame.WIDTH, frame.HEIGHT); frame.paintAll(g); g.setColor(Color.black); g.dispose(); } /** Gets the graphics context for the display. The ScreenManager uses double buffering, so applications must call update() to show any graphics drawn. <p> The application must dispose of the graphics object. */ public Graphics2D getGraphics() { Window window = device.getFullScreenWindow(); if (window != null) { BufferStrategy strategy = window.getBufferStrategy(); return (Graphics2D)strategy.getDrawGraphics(); } else { return null; } } /** Updates the display. */ public void update() { Window window = device.getFullScreenWindow(); if (window != null) { BufferStrategy strategy = window.getBufferStrategy(); if (!strategy.contentsLost()) { strategy.show(); } } // Sync the display on some systems. // (on Linux, this fixes event queue problems) Toolkit.getDefaultToolkit().sync(); } /** Returns the window currently used in full screen mode. Returns null if the device is not in full screen mode. */ public Window getFullScreenWindow() { return device.getFullScreenWindow(); } /** Returns the width of the window currently used in full screen mode. Returns 0 if the device is not in full screen mode. */ public int getWidth() { Window window = device.getFullScreenWindow(); if (window != null) { return window.getWidth(); } else { return 0; } } /** Returns the height of the window currently used in full screen mode. Returns 0 if the device is not in full screen mode. */ public int getHeight() { Window window = device.getFullScreenWindow(); if (window != null) { return window.getHeight(); } else { return 0; } } /** Restores the screen's display mode. */ public void restoreScreen() { Window window = device.getFullScreenWindow(); if (window != null) { window.dispose(); } device.setFullScreenWindow(null); } /** Creates an image compatible with the current display. */ public BufferedImage createCompatibleImage(int w, int h, int transparency) { Window window = device.getFullScreenWindow(); if (window != null) { GraphicsConfiguration gc = window.getGraphicsConfiguration(); return gc.createCompatibleImage(w, h, transparency); } return null; } } Animation: import java.awt.Color; import java.awt.Graphics; import java.awt.Graphics2D; import java.awt.Image; import java.awt.Polygon; import java.awt.image.BufferedImage; import java.util.ArrayList; import java.util.List; /** The Animation class manages a series of images (frames) and the amount of time to display each frame. */ public class Animation { private ArrayList frames; private int currFrameIndex; private long animTime; private long totalDuration; /** Creates a new, empty Animation. */ public Animation() { frames = new ArrayList(); totalDuration = 0; start(); } /** Adds an image to the animation with the specified duration (time to display the image). */ public synchronized void addFrame(BufferedImage image, long duration){ ScreenManager s = new ScreenManager(); totalDuration += duration; frames.add(new AnimFrame(image, totalDuration)); } /** Starts the animation over from the beginning. */ public synchronized void start() { animTime = 0; currFrameIndex = 0; } /** Updates the animation's current image (frame), if necessary. */ public synchronized void update(long elapsedTime) { if (frames.size() >= 1) { animTime += elapsedTime; /*if (animTime >= totalDuration) { animTime = animTime % totalDuration; currFrameIndex = 0; }*/ while (animTime > getFrame(0).endTime) { frames.remove(0); } } } /** Gets the Animation's current image. Returns null if this animation has no images. */ public synchronized Image getImage() { if (frames.size() > 0&&!(currFrameIndex>=frames.size())) { return getFrame(currFrameIndex).image; } else{ System.out.println("There are no frames!"); System.exit(0); } return null; } private AnimFrame getFrame(int i) { return (AnimFrame)frames.get(i); } private class AnimFrame { Image image; long endTime; public AnimFrame(Image image, long endTime) { this.image = image; this.endTime = endTime; } } public void setNewPolyFrame(List<Polygon> polys,int imagewidth,int imageheight,int time){ BufferedImage image=new BufferedImage(imagewidth, imageheight, 1); Graphics g=image.getGraphics(); for(int i=0;i<polys.size();i++){ g.drawPolygon(polys.get(i)); } addFrame(image,time); g.dispose(); } }

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  • Animation Color [on hold]

    - by user2425429
    I'm having problems in my java program for animation. I'm trying to draw a hexagon with a shape similar to that of a trapezoid. Then, I'm making it move to the right for a certain amount of time (DEMO_TIME). Animation and ScreenManager are "API" classes, and AnimationTest1 is a demo. In my test program, it runs with a black screen and white stroke color. I'd like to know why this happened and how to fix it. I'm a beginner, so I apologize for this question being stupid to all you game programmers. Here is the code I have now: import java.awt.DisplayMode; import java.awt.Graphics; import java.awt.Graphics2D; import java.awt.Image; import java.awt.Polygon; import java.util.ArrayList; import java.util.List; import java.util.concurrent.Executor; import java.util.concurrent.Executors; import javax.swing.ImageIcon; public class AnimationTest1 { public static void main(String args[]) { AnimationTest1 test = new AnimationTest1(); test.run(); } private static final DisplayMode POSSIBLE_MODES[] = { new DisplayMode(800, 600, 32, 0), new DisplayMode(800, 600, 24, 0), new DisplayMode(800, 600, 16, 0), new DisplayMode(640, 480, 32, 0), new DisplayMode(640, 480, 24, 0), new DisplayMode(640, 480, 16, 0) }; private static final long DEMO_TIME = 4000; private ScreenManager screen; private Image bgImage; private Animation anim; public void loadImages() { // create animation List<Polygon> polygons=new ArrayList(); int[] x=new int[]{20,4,4,20,40,56,56,40}; int[] y=new int[]{20,32,40,44,44,40,32,20}; polygons.add(new Polygon(x,y,8)); anim = new Animation(); //# of frames long startTime = System.currentTimeMillis(); long currTimer = startTime; long elapsedTime = 0; boolean animated = false; Graphics2D g = screen.getGraphics(); int width=200; int height=200; while (currTimer - startTime < DEMO_TIME*2) { //draw the polygons if(!animated){ for(int j=0; j<polygons.size();j++){ for(int pos=0; pos<polygons.get(j).npoints; pos++){ polygons.get(j).xpoints[pos]+=1; } } anim.setNewPolyFrame(polygons , width , height , 64); } else{ // update animation anim.update(elapsedTime); draw(g); g.dispose(); screen.update(); try{ Thread.sleep(20); } catch(InterruptedException ie){} } if(currTimer - startTime == DEMO_TIME) animated=true; elapsedTime = System.currentTimeMillis() - currTimer; currTimer += elapsedTime; } } public void run() { screen = new ScreenManager(); try { DisplayMode displayMode = screen.findFirstCompatibleMode(POSSIBLE_MODES); screen.setFullScreen(displayMode); loadImages(); } finally { screen.restoreScreen(); } } public void draw(Graphics g) { // draw background g.drawImage(bgImage, 0, 0, null); // draw image g.drawImage(anim.getImage(), 0, 0, null); } } ScreenManager: import java.awt.Color; import java.awt.DisplayMode; import java.awt.Graphics; import java.awt.Graphics2D; import java.awt.GraphicsConfiguration; import java.awt.GraphicsDevice; import java.awt.GraphicsEnvironment; import java.awt.Toolkit; import java.awt.Window; import java.awt.event.KeyListener; import java.awt.event.MouseListener; import java.awt.image.BufferStrategy; import java.awt.image.BufferedImage; import javax.swing.JFrame; import javax.swing.JPanel; public class ScreenManager extends JPanel { private GraphicsDevice device; /** Creates a new ScreenManager object. */ public ScreenManager() { GraphicsEnvironment environment=GraphicsEnvironment.getLocalGraphicsEnvironment(); device = environment.getDefaultScreenDevice(); setBackground(Color.white); } /** Returns a list of compatible display modes for the default device on the system. */ public DisplayMode[] getCompatibleDisplayModes() { return device.getDisplayModes(); } /** Returns the first compatible mode in a list of modes. Returns null if no modes are compatible. */ public DisplayMode findFirstCompatibleMode( DisplayMode modes[]) { DisplayMode goodModes[] = device.getDisplayModes(); for (int i = 0; i < modes.length; i++) { for (int j = 0; j < goodModes.length; j++) { if (displayModesMatch(modes[i], goodModes[j])) { return modes[i]; } } } return null; } /** Returns the current display mode. */ public DisplayMode getCurrentDisplayMode() { return device.getDisplayMode(); } /** Determines if two display modes "match". Two display modes match if they have the same resolution, bit depth, and refresh rate. The bit depth is ignored if one of the modes has a bit depth of DisplayMode.BIT_DEPTH_MULTI. Likewise, the refresh rate is ignored if one of the modes has a refresh rate of DisplayMode.REFRESH_RATE_UNKNOWN. */ public boolean displayModesMatch(DisplayMode mode1, DisplayMode mode2) { if (mode1.getWidth() != mode2.getWidth() || mode1.getHeight() != mode2.getHeight()) { return false; } if (mode1.getBitDepth() != DisplayMode.BIT_DEPTH_MULTI && mode2.getBitDepth() != DisplayMode.BIT_DEPTH_MULTI && mode1.getBitDepth() != mode2.getBitDepth()) { return false; } if (mode1.getRefreshRate() != DisplayMode.REFRESH_RATE_UNKNOWN && mode2.getRefreshRate() != DisplayMode.REFRESH_RATE_UNKNOWN && mode1.getRefreshRate() != mode2.getRefreshRate()) { return false; } return true; } /** Enters full screen mode and changes the display mode. If the specified display mode is null or not compatible with this device, or if the display mode cannot be changed on this system, the current display mode is used. <p> The display uses a BufferStrategy with 2 buffers. */ public void setFullScreen(DisplayMode displayMode) { JFrame frame = new JFrame(); frame.setUndecorated(true); frame.setIgnoreRepaint(true); frame.setResizable(true); device.setFullScreenWindow(frame); if (displayMode != null && device.isDisplayChangeSupported()) { try { device.setDisplayMode(displayMode); } catch (IllegalArgumentException ex) { } } frame.createBufferStrategy(2); Graphics g=frame.getGraphics(); g.setColor(Color.white); g.drawRect(0, 0, frame.WIDTH, frame.HEIGHT); frame.paintAll(g); g.setColor(Color.black); g.dispose(); } /** Gets the graphics context for the display. The ScreenManager uses double buffering, so applications must call update() to show any graphics drawn. <p> The application must dispose of the graphics object. */ public Graphics2D getGraphics() { Window window = device.getFullScreenWindow(); if (window != null) { BufferStrategy strategy = window.getBufferStrategy(); return (Graphics2D)strategy.getDrawGraphics(); } else { return null; } } /** Updates the display. */ public void update() { Window window = device.getFullScreenWindow(); if (window != null) { BufferStrategy strategy = window.getBufferStrategy(); if (!strategy.contentsLost()) { strategy.show(); } } // Sync the display on some systems. // (on Linux, this fixes event queue problems) Toolkit.getDefaultToolkit().sync(); } /** Returns the window currently used in full screen mode. Returns null if the device is not in full screen mode. */ public Window getFullScreenWindow() { return device.getFullScreenWindow(); } /** Returns the width of the window currently used in full screen mode. Returns 0 if the device is not in full screen mode. */ public int getWidth() { Window window = device.getFullScreenWindow(); if (window != null) { return window.getWidth(); } else { return 0; } } /** Returns the height of the window currently used in full screen mode. Returns 0 if the device is not in full screen mode. */ public int getHeight() { Window window = device.getFullScreenWindow(); if (window != null) { return window.getHeight(); } else { return 0; } } /** Restores the screen's display mode. */ public void restoreScreen() { Window window = device.getFullScreenWindow(); if (window != null) { window.dispose(); } device.setFullScreenWindow(null); } /** Creates an image compatible with the current display. */ public BufferedImage createCompatibleImage(int w, int h, int transparency) { Window window = device.getFullScreenWindow(); if (window != null) { GraphicsConfiguration gc = window.getGraphicsConfiguration(); return gc.createCompatibleImage(w, h, transparency); } return null; } } Animation: import java.awt.Color; import java.awt.Graphics; import java.awt.Graphics2D; import java.awt.Image; import java.awt.Polygon; import java.awt.image.BufferedImage; import java.util.ArrayList; import java.util.List; /** The Animation class manages a series of images (frames) and the amount of time to display each frame. */ public class Animation { private ArrayList frames; private int currFrameIndex; private long animTime; private long totalDuration; /** Creates a new, empty Animation. */ public Animation() { frames = new ArrayList(); totalDuration = 0; start(); } /** Adds an image to the animation with the specified duration (time to display the image). */ public synchronized void addFrame(BufferedImage image, long duration){ ScreenManager s = new ScreenManager(); totalDuration += duration; frames.add(new AnimFrame(image, totalDuration)); } /** Starts the animation over from the beginning. */ public synchronized void start() { animTime = 0; currFrameIndex = 0; } /** Updates the animation's current image (frame), if necessary. */ public synchronized void update(long elapsedTime) { if (frames.size() >= 1) { animTime += elapsedTime; /*if (animTime >= totalDuration) { animTime = animTime % totalDuration; currFrameIndex = 0; }*/ while (animTime > getFrame(0).endTime) { frames.remove(0); } } } /** Gets the Animation's current image. Returns null if this animation has no images. */ public synchronized Image getImage() { if (frames.size() > 0&&!(currFrameIndex>=frames.size())) { return getFrame(currFrameIndex).image; } else{ System.out.println("There are no frames!"); System.exit(0); } return null; } private AnimFrame getFrame(int i) { return (AnimFrame)frames.get(i); } private class AnimFrame { Image image; long endTime; public AnimFrame(Image image, long endTime) { this.image = image; this.endTime = endTime; } } public void setNewPolyFrame(List<Polygon> polys,int imagewidth,int imageheight,int time){ BufferedImage image=new BufferedImage(imagewidth, imageheight, 1); Graphics g=image.getGraphics(); for(int i=0;i<polys.size();i++){ g.drawPolygon(polys.get(i)); } addFrame(image,time); g.dispose(); } }

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  • how to solve unhandled exception error when using visual C++ 2008?

    - by make
    Hi, Could someone please help me to solve unhandled exception error when using visual C++ 2008? the error is displayed as follow: Unhandled exception at 0x00411690 in time.exe: 0xC0000005: Access violation reading location 0x00000008 Actually when I used visual c++ 6 in the past, there weren't any error and the program was running fine. But now ehen I use visual 2008, I am getting this Unhandled exception error. Here is the program: #include <stdio.h> #include <stdlib.h> #include <time.h> #ifdef _WIN32 // #include <winsock.h> #include <windows.h> #include "stdint.h" // typedef __int64 int64_t // Define it from MSVC's internal type // typedef unsigned __int32 uint32_t #else #include <stdint.h> // Use the C99 official header #include <sys/time.h> #include <unistd.h> #endif #if defined(_MSC_VER) || defined(_MSC_EXTENSIONS) #define DELTA_EPOCH_IN_MICROSECS 11644473600000000Ui64 #else #define DELTA_EPOCH_IN_MICROSECS 11644473600000000ULL #endif struct timezone { int tz_minuteswest; /* minutes W of Greenwich */ int tz_dsttime; /* type of dst correction */ }; #define TEST #ifdef TEST uint32_t stampstart(); uint32_t stampstop(uint32_t start); int main() { uint32_t start, stop; start = stampstart(); /* Your code goes here */ stop = stampstop(start); return 0; } #endif int gettimeofday(struct timeval *tv, struct timezone *tz) { FILETIME ft; unsigned __int64 tmpres = 0; static int tzflag = 0; if (NULL != tv) { GetSystemTimeAsFileTime(&ft); tmpres |= ft.dwHighDateTime; tmpres <<= 32; tmpres |= ft.dwLowDateTime; tmpres /= 10; /*convert into microseconds*/ /*converting file time to unix epoch*/ tmpres -= DELTA_EPOCH_IN_MICROSECS; tv->tv_sec = (long)(tmpres / 1000000UL); tv->tv_usec = (long)(tmpres % 1000000UL); } if (NULL != tz) { if (!tzflag) { _tzset(); tzflag++; } tz->tz_minuteswest = _timezone / 60; tz->tz_dsttime = _daylight; } return 0; } uint32_t stampstart() { struct timeval tv; struct timezone tz; struct tm *tm; uint32_t start; gettimeofday(&tv, &tz); tm = localtime(&tv.tv_sec); printf("TIMESTAMP-START\t %d:%02d:%02d:%d (~%d ms)\n", tm->tm_hour, tm->tm_min, tm->tm_sec, tv.tv_usec, tm->tm_hour * 3600 * 1000 + tm->tm_min * 60 * 1000 + tm->tm_sec * 1000 + tv.tv_usec / 1000); start = tm->tm_hour * 3600 * 1000 + tm->tm_min * 60 * 1000 + tm->tm_sec * 1000 + tv.tv_usec / 1000; return (start); } uint32_t stampstop(uint32_t start) { struct timeval tv; struct timezone tz; struct tm *tm; uint32_t stop; gettimeofday(&tv, &tz); tm = localtime(&tv.tv_sec); stop = tm->tm_hour * 3600 * 1000 + tm->tm_min * 60 * 1000 + tm->tm_sec * 1000 + tv.tv_usec / 1000; printf("TIMESTAMP-END\t %d:%02d:%02d:%d (~%d ms) \n", tm->tm_hour, tm->tm_min, tm->tm_sec, tv.tv_usec, tm->tm_hour * 3600 * 1000 + tm->tm_min * 60 * 1000 + tm->tm_sec * 1000 + tv.tv_usec / 1000); printf("ELAPSED\t %d ms\n", stop - start); return (stop); } thanks for your replies:

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  • Why is there a Null Pointer Exception in this Java Code?

    - by algorithmicCoder
    This code takes in users and movies from two separate files and computes a user score for a movie. When i run the code I get the following error: Exception in thread "main" java.lang.NullPointerException at RecommenderSystem.makeRecommendation(RecommenderSystem.java:75) at RecommenderSystem.main(RecommenderSystem.java:24) I believe the null pointer exception is due to an error in this particular class but I can't spot it....any thoughts? import java.io.*; import java.lang.Math; public class RecommenderSystem { private Movie[] m_movies; private User[] m_users; /** Parse the movies and users files, and then run queries against them. */ public static void main(String[] argv) throws FileNotFoundException, ParseError, RecommendationError { FileReader movies_fr = new FileReader("C:\\workspace\\Recommender\\src\\IMDBTop10.txt"); FileReader users_fr = new FileReader("C:\\workspace\\Recommender\\src\\IMDBTop10-users.txt"); MovieParser mp = new MovieParser(movies_fr); UserParser up = new UserParser(users_fr); Movie[] movies = mp.getMovies(); User[] users = up.getUsers(); RecommenderSystem rs = new RecommenderSystem(movies, users); System.out.println("Alice would rate \"The Shawshank Redemption\" with at least a " + rs.makeRecommendation("The Shawshank Redemption", "asmith")); System.out.println("Carol would rate \"The Dark Knight\" with at least a " + rs.makeRecommendation("The Dark Knight", "cd0")); } /** Instantiate a recommender system. * * @param movies An array of Movie that will be copied into m_movies. * @param users An array of User that will be copied into m_users. */ public RecommenderSystem(Movie[] movies, User[] users) throws RecommendationError { m_movies = movies; m_users = users; } /** Suggest what the user with "username" would rate "movieTitle". * * @param movieTitle The movie for which a recommendation is made. * @param username The user for whom the recommendation is made. */ public double makeRecommendation(String movieTitle, String username) throws RecommendationError { int userNumber; int movieNumber; int j=0; double weightAvNum =0; double weightAvDen=0; for (userNumber = 0; userNumber < m_users.length; ++userNumber) { if (m_users[userNumber].getUsername().equals(username)) { break; } } for (movieNumber = 0; movieNumber < m_movies.length; ++movieNumber) { if (m_movies[movieNumber].getTitle().equals(movieTitle)) { break; } } // Use the weighted average algorithm here (don't forget to check for // errors). while(j<m_users.length){ if(j!=userNumber){ weightAvNum = weightAvNum + (m_users[j].getRating(movieNumber)- m_users[j].getAverageRating())*(m_users[userNumber].similarityTo(m_users[j])); weightAvDen = weightAvDen + (m_users[userNumber].similarityTo(m_users[j])); } j++; } return (m_users[userNumber].getAverageRating()+ (weightAvNum/weightAvDen)); } } class RecommendationError extends Exception { /** An error for when something goes wrong in the recommendation process. * * @param s A string describing the error. */ public RecommendationError(String s) { super(s); } }

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  • Why I am getting Null from this statement. Query Syntax in C#

    - by Shantanu Gupta
    This is not working. Returns Null to dept_list. var dept_list = ((from map in DtMapGuestDepartment.AsEnumerable() where map.Field<Nullable<long>>("Guest_Id") == 174 select map.Field<Nullable<long>>("Department_id")).Distinct())as IEnumerable<DataRow>; DataTable dt = dept_list.CopyToDataTable(); //dept_list comes null here This works as desired. var dept_list = from map in DtMapGuestDepartment.AsEnumerable() where map.Field<Nullable<long>>("Guest_Id") == 174 select map; DataTable dt = dept_list.CopyToDataTable(); //when used like this runs correct. What mistake is being done by me here. ?

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  • How can I pass a reference to another control as an IValueConverter parameter?

    - by MKing
    I am binding some business objects to a WPF ItemsControl. They are displayed using a custom IValueConverter implementation used to produce the Geometry for a Path object in the DataTemplate as shown here: <ItemsControl x:Name="Display" Background="White" HorizontalAlignment="Stretch" VerticalAlignment="Stretch" ItemsSource="{Binding ElementName=ViewPlaneSelector, Path=SelectedItem.VisibleElements}" > <ItemsControl.Resources> <!-- This object is just used to get around the fact that ConverterParameter can't be a binding directly (it's not a DependencyProperty on a DependencyObject --> <this:GeometryConverterData x:Key="ConverterParameter2" Plane="{Binding ElementName=ViewPlaneSelector, Path=SelectedItem}" /> <DataTemplate DataType="{x:Type o:SlenderMember}"> <Path Stroke="Blue" StrokeThickness=".5" Data='{Binding Converter={StaticResource SlenderMemberConverter}, ConverterParameter={StaticResource ConverterParameter2}}' ToolTip="{Binding AsString}"> </Path> </DataTemplate> </ItemsControl.Resources> </ItemsControl> Note that the items for the ItemsControl are drawn from the ViewPlaneSelector (a ComboBox) SelectedItem.VisibleElements property. I need that same ViewPlaneSelector.SelectedItem in the SlenderMemberConverter to figure out how to display this element. I'm trying to get a reference to it into the converter by creating the intermediate GeometryConverterData object in the Resources section. This object exists solely to get around the problem of not being able to bind directly to the ConverterParameter property (as mentioned in the comments). Here is the code for the GeometryDataConverter class: class GeometryConverterData : FrameworkElement { public static readonly DependencyProperty PlaneProperty = DependencyProperty.Register("Plane", typeof(ViewPlane), typeof(GeometryConverterData), null, ValidValue); public static bool ValidValue(object o){ return true; } public ViewPlane Plane { get{ return GetValue(PlaneProperty) as ViewPlane; }set{ SetValue(PlaneProperty, value); } } } I added the ValidValue function for debugging, to see what this property was getting bound it. It only and always gets set to null. I know that the ViewPlaneSelector.SelectedItem isn't always null since the ItemsControl has items, and it's items are drawn from the same property on the same object... so what gives? How can I get a reference to this ComboBox into my ValueConverter. Or, alternately, why is what I'm doing silly and overly complicated. I'm as guilty as many of sometimes getting it into my head that something has to be done a certain way and then killing myself to make it happen when there's a much cleaner and simpler solution.

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  • Display empty textbox using Html.TextBoxFor on a not-null property in an EF entity.

    - by hungster
    I am using Entity Framework (v4) entities. I have an entity called Car with a Year property of type integer. The Year property does not allow NULL. I have the following in my Create view: <%= Html.TextBoxFor(model => model.Year) %> I am required to return a new Car object (due to other requirements) in my HttpGet Create action in the CarController. Currently, a zero is displayed in the Year textbox because the Year property does not allow NULL. I would like to display an empty textbox in the Create view. How do I do this?

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  • Why do I keep on getting an exception-illegal operation on ResultSet?

    - by eli1987
    Here is the code-admittedly I'm terrible at Java, but surely I catch a null result set with the if....else statement....sorry its the whole Class: /* * To change this template, choose Tools | Templates * and open the template in the editor. */ /* * SearchParts.java * * Created on 08-Mar-2010, 12:14:31 */ package garits; import java.sql.*; import javax.swing.*; /** * * @author Deniz */ public class SearchParts extends javax.swing.JFrame { /** Creates new form SearchParts */ public SearchParts() { initComponents(); } /** This method is called from within the constructor to * initialize the form. * WARNING: Do NOT modify this code. The content of this method is * always regenerated by the Form Editor. */ @SuppressWarnings("unchecked") private void jButton1ActionPerformed(java.awt.event.ActionEvent evt) { if (!jTextField1.getText().equals("")) { String result = ""; int Partnumber = Integer.parseInt(jTextField1.getText()); DB db = new DB(); try { db.connect(); String query = "Select * from Stock Where Part_no =" + "'" + jTextField1.getText() + "'"; ResultSet rs = db.execSQL(query); if (rs.equals(null)) { PartNotFound nf = new PartNotFound(); nf.setVisible(true); } else { ResultSetMetaData rsmd = rs.getMetaData(); int numberOfColumns = rsmd.getColumnCount(); int RowCount = 0; for (int i = 1; i < numberOfColumns; i++) { rs.getString(i); result += i + "/n"; } if (!result.equals("")) { Receptionist_FranchiseePartFound part = new Receptionist_FranchiseePartFound(); part.setVisible(true); while (rs.next()) { RowCount++; } part.getTable().addRowSelectionInterval(0, RowCount); } else { PartNotFound nf = new PartNotFound(); } } } catch (Exception e) { e.printStackTrace(); JOptionPane.showMessageDialog(jButton1, "More information needed for search", "Error Message", JOptionPane.ERROR_MESSAGE); } } else if (!jTextField2.getText().equals("")) { String result = ""; DB db = new DB(); try { db.connect(); String query = "Select * from Stock Where Part_name =" + "'" + jTextField2.getText() + "'"; ResultSet rs = db.execSQL(query); if (rs.equals(null)) { PartNotFound nf = new PartNotFound(); nf.setVisible(true); } else { ResultSetMetaData rsmd = rs.getMetaData(); int numberOfColumns = rsmd.getColumnCount(); int RowCount = 0; for (int i = 1; i < numberOfColumns; i++) { rs.getString(i); result += i + "/n"; } // Receptionist_FranchiseePartFound part = new Receptionist_FranchiseePartFound(); // part.setVisible(true); if (!result.equals("")) { Receptionist_FranchiseePartFound part = new Receptionist_FranchiseePartFound(); part.setVisible(true); while (rs.next()) { RowCount++; } part.getTable().addRowSelectionInterval(0, RowCount); } else { PartNotFound nf = new PartNotFound(); nf.setVisible(true); } } } catch (Exception e) { e.printStackTrace(); JOptionPane.showMessageDialog(jButton1, "More information needed for search", "Error Message", JOptionPane.ERROR_MESSAGE); } } else if (jTextField1.getText().equals("") && jTextField2.getText().equals("")) { String result = ""; DB db = new DB(); try { db.connect(); String query = "Select * from Stock Where Manufacturer =" + "'" + jTextField3.getText() + "'AND Vehicle_type ='" + jTextField4.getText() + "'"; ResultSet rs = db.execSQL(query); if (rs.equals(null)) { PartNotFound nf = new PartNotFound(); nf.setVisible(true); } else{ ResultSetMetaData rsmd = rs.getMetaData(); int numberOfColumns = rsmd.getColumnCount(); int RowCount = 0; for (int i = 1; i < numberOfColumns; i++) { rs.getString(i); result += i + "/n"; } // Receptionist_FranchiseePartFound part = new Receptionist_FranchiseePartFound(); // part.setVisible(true); if (!result.equals("")) { Receptionist_FranchiseePartFound part = new Receptionist_FranchiseePartFound(); part.setVisible(true); while (rs.next()) { RowCount++; } part.getTable().addRowSelectionInterval(0, RowCount); } else { PartNotFound nf = new PartNotFound(); nf.setVisible(true); } } } catch (Exception e) { e.printStackTrace(); JOptionPane.showMessageDialog(jButton1, "More information needed for search", "Error Message", JOptionPane.ERROR_MESSAGE); } } else if (jTextField3.getText().equals("") || jTextField4.getText().equals("")) { JOptionPane.showMessageDialog(jButton1, "More information needed for search", "Error Message", JOptionPane.ERROR_MESSAGE); } } /** * @param args the command line arguments */ // Variables declaration - do not modify private javax.swing.JButton jButton1; private javax.swing.JButton jButton2; private javax.swing.JLabel jLabel1; private javax.swing.JLabel jLabel2; private javax.swing.JLabel jLabel3; private javax.swing.JLabel jLabel4; private javax.swing.JLabel jLabel5; private javax.swing.JLabel jLabel6; private javax.swing.JLabel jLabel7; private javax.swing.JLabel jLabel8; private javax.swing.JTextField jTextField1; private javax.swing.JTextField jTextField2; private javax.swing.JTextField jTextField3; private javax.swing.JTextField jTextField4; // End of variables declaration }

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  • NSData to NSString by changing the value null is returned. I need you help

    - by kevin
    *cipher.h, cipher.m all code : http://watchitlater.com/blog/2010/02/java-and-iphone-aes-interoperability Cipher.m -(NSData *)encrypt:(NSData *)plainText{ return [self transform:KCCEncrypt data:plainText; } step1. Cipher *cipher = [[Cipher alloc]initWithKey:@"1234567890"]; NSData *input = [@"kevin" dataUsingEncoding:NSUTF8StringEncoding]; NSData *data = [cipher encrypt:input]; data variables NSLog print : <4d1c4d7f 1592718c fd588cec 84053e35 step2. NSString *changeVal = [[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding]; data variables NSLog print : null NSData to NSString by changing the value null is returned. By converting NSString NSURLConnection want to transfer. I need you help

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  • Adding a custom control to a page, then adding multiple custom children into that one, null user con

    - by Rickjaah
    Hello all, While nerding my way through the day again. I came across a problem concerning adding children to an already add child control. I can add the controls, but when trying to use the controls in the added control, they all return null. This is the method: protected override CreateChildControls(EventArgs e) { UserControl uControl = LoadControl("~/controls/TwoColumn.ascx"); PlaceHolder holder = uControl.Controls.FindControl(phrContentMiddle) as PlaceHolder; holder.Controls.Add(LoadControl("~/controls/ImageShowControl"); } When i try to call any type of button/UserControl inside the ImageShowControl.... All return null. Is this something in the Page LifeCycle? If so, what is the way to go to realize this?

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  • Why is e.Item.DataItem null on ItemDataBound event when binding an asp:net Repeater to a Collection?

    - by Clean
    Hi, I'm trying to bind a collection implementing the ICollection, IEnumerable and IList interface to an asp.net repeater. The Collection is named CustomCollection. So I'm setting the datasource of the repeater to the collection, as follows: rptRepeater.DataSource = customCollection; rptRepeater.Databind(); Then, on the ItemDataBound event, I'm trying to access the DataItem object, as follow: void rptRepeater_ItemDataBound(object sender, RepeaterItemEventArgs e){ object obj = e.Item.DataItem; // DataItem is null for some reason } For some reason the e.Item.DataItem object is null. Do anyone know why this is, and/or what I could do to get hold of the object in the collection that is to be databound to the repeater? Thanx!

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  • Does delegate chaining have to start with a null Delegate?

    - by MCS
    In CLR via C#, Jeffrey Richter gives the following example of delegate chaining (pg. 406): internal delegate void Feedback(Int 32 value); Feedback fb1 = new Feedback(method1); // in the book, these methods Feedback fb2 = new Feedback(method2); // have different names Feedback fb3 = new Feedback(method3); Feedback fbChain = null; fbChain = (Feedback) Delegate.Combine(fbChain, fb1); fbChain = (Feedback) Delegate.Combine(fbChain, fb2); fbChain = (Feedback) Delegate.Combine(fbChain, fb3); Why does the first call to Delegate.Combine have to pass in a null Delegate? Here's how I would have thought it should be written: Feedback fbChain = (Feedback) Delegate.Combine(fb1, fb2); fbChain = (Feedback) Delegate.Combine(fbchain, fb3);

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  • Does a System.DirectoryServices.AccountManagement.Principal ever have a null GUID?

    - by Josh
    I have a situation where I need to store a globally unique identifier that points to an Active Directory user account. I'm leaning towards the Guid because it is easier to store than the Sid. According to the MSDN entry, the property (which is a Nullable), will always return null if the ContextType is set to "Machine." I don't need to worry about this because our ContextType will always be set to "Domain." My question is, will this property ever return null if the ContextType is "Domain"? In other words, will an account in an AD DS store always have a Guid?

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  • Why does RIGHT(@foostr, 0) return NULL when @foostr is varchar(max)?

    - by bob-montgomery
    In SQL Server 2005 If I want to find the right-most one character of a varchar(max) variable, no problem: declare @foostr varchar(max) set @foostr = 'abcd' select right (@foostr, 1) ---- d If I want to find the right-most zero characters of a string literal, no problem: select right ('abcd', 0) ------------------ It returns an empty string. If I want to find the right-most zero characters of a varchar(10), no problem: declare @foostr varchar(10) set @foostr = 'abcd' select right (@foostr, 0) ---- It returns an empty string. If I want to find the right-most zero characters of a varchar(max), well: declare @foostr varchar(max) set @foostr = 'abcd' select right (@foostr, 0) ---- NULL It returns NULL. Why?

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  • Why can't I inject value null with Ninjects ConstructorArgument?

    - by stiank81
    When using Ninjects ConstructorArgument you can specify the exact value to inject to specific parameters. Why can't this value be null, or how can I make it work? Maybe it's not something you'd like to do, but I want to use it in my unit tests.. Example: public class Ninja { private readonly IWeapon _weapon; public Ninja(IWeapon weapon) { _weapon = weapon; } } public void SomeFunction() { var kernel = new StandardKernel(); var ninja = kernel.Get<Ninja>(new ConstructorArgument("weapon", null)); }

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  • Is it ok to return a reference of a function scope static variable?

    - by kartik
    I wanted to know if that has any ill effects under any circumsatnce. For ex: Ex1: void* func1() { void* p_ref = NULL; //function scope static variable static int var1 = 2; p_ref = &var1; return p_ref; } Ex2: //file scope static variable static int var2 = 2; void* func2() { void* p_ref = NULL; var2 = 3; p_ref = &var2; return p_ref; } So in the above two cases what is the difference apart from the fact that var1 is function scope and var2 is file scope. Thanks in advance.

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  • Is there a work-around that allows missing data to equal NULL for LOAD DATA INFILE in MySQL?

    - by richardh
    I have a lot of large csv files with NULL values stored as ,, (i.e., no entry). After a lot of searching I found that this is a known "bug", although it may be a feature for some users. Is there a way that I can fix this on the fly without pre-processing? These data are all numeric, so a zero value is very different from NULL. Or if I have to do pre-processing, is there one that is most promising for dealing with tens of csv files of 100mb to 1gb? Thanks!

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  • Delete last 3 lines within while ((line = r.ReadLine()) != null) but not open a new text file to delete the lines?

    - by user1473672
    This is the code I've seen so far to delete last 3 lines in a text file, but it's required to determine string[] lines = File.ReadAllLines(); which is nt necessary for me to do so. string[] lines = File.ReadAllLines(@"C:\\Users.txt"); StringBuilder sb = new StringBuilder(); int count = lines.Length - 3; // except last 3 lines for (int s = 0; s < count; s++) { sb.AppendLine(lines[s]); } The code works well, but I don't wanna re-read the file as I've mentioned the streamreader above : using (StreamReader r = new StreamReader(@"C:\\Users.txt")) Im new to C#, as far as I know, after using streamreader, and if I wanna modify the lines, I have to use this : while ((line = r.ReadLine()) != null) { #sample codes inside the bracket line = line.Replace("|", ""); line = line.Replace("MY30", ""); line = line.Replace("E", ""); } So, is there any way to delete the last 3 lines in the file within the "while ((line = r.ReadLine()) != null)" ?? I have to delete lines, replace lines and a few more modications in one shot, so I can't keep opening/reading the same text file again and again to modify the lines. I hope the way I ask is understable for you guys .< Plz help me, I know the question sounds simple but I've searched so many ways to solve it but failed =( So far, my code is : using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.IO; namespace ConsoleApplication11 { public class Read { static void Main(string[] args) { string tempFile = Path.GetTempFileName(); using (StreamReader r = new StreamReader(@"C:\\Users\SAP Report.txt")) { using (StreamWriter sw = new StreamWrite (@"C:\\Users\output2.txt")) { string line; while ((line = r.ReadLine()) != null) { line = line.Replace("|", ""); line = line.Replace("MY30", ""); line = line.Replace("E", ""); line = System.Text.RegularExpressions.Regex.Replace(line, @"\s{2,}", " "); sw.WriteLine(line); } } } } } } Now my next task is to delete the last 3 lines in the file after these codes, and I need help on this one. Thank you.

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  • what difference between NULL, blank and empty in php?

    - by I Like PHP
    i have one form which have some input box and some select box. i want to apply that nothing can be empty or blank before further activity, so i use below condition foreach($_POST as $k=>$v) { if($v=='' || $v==NULL || empty($v)) { $_SESSION['errMsg']=' Please fill all the fields properly'; header("location:somepage.php"); exit; } } now my question is: above if is useful or not? if not then which condition is enough to prevent blank entry $v=='' or $v==NULL or empty($v) or i have to use all of these conditions? Thanks in advance

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  • Why is MenuItem.AdapterContextMenuInfo null when my list view has a custom adapter?

    - by gregm
    My question: Before I go and use an OnLongClickListener, is there a better way to pass the "what was clicked to create this context menu" information when your list view has a custom adapter? Here are some details: Normally, my code can just do something like this: public boolean onContextItemSelected(MenuItem item) { AdapterContextMenuInfo info = (AdapterContextMenuInfo) item.getMenuInfo(); and then go on and be happy. However, ever since I introduced a custom adapter, item.getMenuInfo() is null. This is a big problem, because my code no longer knows which item was clicked. (My custom Adapter makes each list row a checkbox and a text view) I tried this but failed: Created my own special AdapterContextMenuInfo (called "HasAViewMenuInfo"), but when I pass it in this method, it ends up being null in the menu public void onCreateContextMenu(ContextMenu menu, View v, ContextMenuInfo menuInfo) { super.onCreateContextMenu(menu, v, new HasAViewMenuInfo(v));

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  • How can I get a set of radio buttons to accept NULL (nothing checked)?

    - by Ethan
    I'm working on a Rails application where I have some a set of two radio buttons where users can click "yes" or "no". The MySQL DB column created by the ActiveRecord migration is a tinyint. If the user doesn't click either radio button I want MySQL to store NULL. (The column allows NULL.) And when they come back to edit the data, neither button should be checked. What's happening is that ActiveRecord is storing 0 and then when I come back the "No" button is checked. Rails 2.3.5 Form code (I'm using Haml): = f.radio_button( :model_attribute, true ) Yes = f.radio_button( :model_attribute, false ) No (In retrospect it probably would have been better to use a single checkbox, but it would be difficult to change that now.)

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