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  • CodePlex Daily Summary for Monday, October 08, 2012

    CodePlex Daily Summary for Monday, October 08, 2012Popular ReleasesSofire Suite v1.6: XSqlModelGenerator.AddIn: 1、?? VS2010/2012 2、?? .NET FRAMEWORK 2.0 3、?? SOFIRE V1.6Sofire XSql: XSqlFormDemo: ???? MSSQL ???????ClosedXML - The easy way to OpenXML: ClosedXML 0.68.0: ClosedXML now resolves formulas! Yes it finally happened. If you call cell.Value and it has a formula the library will try to evaluate the formula and give you the result. For example: var wb = new XLWorkbook(); var ws = wb.AddWorksheet("Sheet1"); ws.Cell("A1").SetValue(1).CellBelow().SetValue(1); ws.Cell("B1").SetValue(1).CellBelow().SetValue(1); ws.Cell("C1").FormulaA1 = "\"The total value is: \" & SUM(A1:B2)"; var...Picturethrill: Version 2.10.7.0: Major FeaturesWindows 8 Support!!! Picturethrill is fully tested on latest Windows 8. Try it now.New AboutPicturethrill Dialog Available from "Advanced" window. Describes Version, Developers and other infoFull Installation Information in Control Panel Picturethrill in ControlPanel has full information, including Version and Size. Minor Bug FixesImproved Logging AppDomain Unhandled Exception Logging Delete WallpaperDownload Folder (Saves Diskspace) Advanced Settings "Close" button bug ...VidCoder: 1.4.3 Beta: Fixed crash on switching container types. Updated subtitle selection to only allow one PGS subtitle to be selected under an MP4 container as PGS passthrough in MP4 is not supported and the sub must be burned in.Microsoft Ajax Minifier: Microsoft Ajax Minifier 4.68: Fixes for issues: 17110 - added support for -moz-calc or -webkit-calc to previous fix for calc support. 18652 - if being run under Mono runtime, don't mistake UNIX-style paths for command-line switches. 18659 - added capability to specify JS settings for CSS files that have JS embedded in expressions. Did a lot of internal house-keeping: add DLL support for -pponly switch. Add support for -js:expr, -js:evt, and -js:json to allow easy parsing for expressions, event handlers, and JSON code...Json.NET: Json.NET 4.5 Release 10: New feature - Added Portable build to NuGet package New feature - Added GetValue and TryGetValue with StringComparison to JObject Change - Improved duplicate object reference id error message Fix - Fixed error when comparing empty JObjects Fix - Fixed SecAnnotate warnings Fix - Fixed error when comparing DateTime JValue with a DateTimeOffset JValue Fix - Fixed serializer sometimes not using DateParseHandling setting Fix - Fixed error in JsonWriter.WriteToken when writing a DateT...Readable Passphrase Generator: KeePass Plugin 0.7.2: Changes: Tested against KeePass 2.20.1 Tested under Ubuntu 12.10 (and KeePass 2.20) Added GenerateAsUtf8 method returning the encrypted passphrase as a UTF8 byte array.JSLint for Visual Studio 2010: 1.4.2: 1.4.2GPdotNET - artificial intelligence tool: GPdotNET v2 BETA3: This is hopefully the last beta before final version.RiP-Ripper & PG-Ripper: PG-Ripper 1.4.02: changes NEW: Added Support Big Naturals Only forum NEW: Added Setting to enable/disable "Show last download image"patterns & practices: Prism: Prism for .NET 4.5: This is a release does not include any functionality changes over Prism 4.1 Desktop. These assemblies target .NET 4.5. These assemblies also were compiled against updated dependencies: Unity 3.0 and Common Service Locator (Portable Class Library).WinRT XAML Toolkit: WinRT XAML Toolkit - 1.3.2: WinRT XAML Toolkit based on the Windows 8 RTM SDK. Download the latest source from the SOURCE CODE page. For compiled version use NuGet. You can add it to your project in Visual Studio by going to View/Other Windows/Package Manager Console and entering: PM> Install-Package winrtxamltoolkit Features AsyncUI extensions Controls and control extensions Converters Debugging helpers Imaging IO helpers VisualTree helpers Samples Recent changes NOTE: Namespace changes DebugConsol...Snoop, the WPF Spy Utility: Snoop 2.8.0: Snoop 2.8.0Announcing Snoop 2.8.0! It's been exactly six months since the last release, and this one has a bunch of goodies in it. In particular, there is now a PowerShell scripting tab, compliments of Bailey Ling. With this tab, the possibilities are limitless. It basically lets you automate/script the application that you are Snooping. Bailey has a couple blog posts (one and two) on his tab already, and I am sure more is to come. Please note that if you do not have PowerShell installed, y....NET Micro Framework: .NET MF 4.3 (Beta): This is the 4.3 Beta version of the .NET Micro Framework. Feature List for v4.3 Support for Visual Studio 2012 (including the Windows Desktop Express version) All v4.2 QFEs features and bug fixes (PWM enhancements, lwIP and network driver reliability improvements, Analog Output, WinUSB and latest GCC support) Improved diagnostic information for deployment Decreased boot time Bug fixes Work Item 1736 - Create link for MFDeploy under start menu Work Item 1504 - Customizing lwIP o...MCEBuddy 2.x: MCEBuddy 2.3.1: 2.3.1All new Remote Client Server architecture. Reccomended Download. The Remote Client Installation is OPTIONAL, you can extract the files from the zip archive into a local folder and run MCEBuddy.GUI directly. 2.2.15 was the last standalone release. Changelog for 2.3.1 (32bit and 64bit) 1. All remote MCEBuddy Client Server architecture (GUI runs remotely/independently from engine now) 2. Fixed bug in Audio Offset 3. Added support for remote MediaInfo (right click on file in queue to get ...D3 Loot Tracker: 1.5: Support for session upload to website. Support for theme change through general settings. Time played counter will now also display a count for days. Tome of secrets are no longer logged as items.Team Foundation Server Word Add-in: Version 1.0.12.0622: Welcome to the Visual Studio Team Foundation Server Word Add-in Supported Environments Microsoft Office Word 2007 and 2010 X86 (32-bit) Team Foundation Server 2010 Object Model TFS 2010, 2012 and TFS Service supported, using TFS OM / Explorer 2010. Quality-Bar Details Tool has been reviewed by Visual Studio ALM Rangers Tool has been through an independent technical and quality review All critical bugs have been resolved Known Issues / Bugs WI#43553 - The Acceptance criteria is not pu...DirectX Tool Kit: October 2012: October 2, 2012 Added ScreenGrab module Added CreateGeoSphere for drawing a geodesic sphere Put DDSTextureLoader and WICTextureLoader into the DirectX C++ namespace Renamed project files for better naming consistency Updated WICTextureLoader for Windows 8 96bpp floating-point formats Win32 desktop projects updated to use Windows Vista (0x0600) rather than Windows 7 (0x0601) APIs Tweaked SpriteBatch.cpp to workaround ARM NEON compiler codegen bugCRM 2011 Visual Ribbon Editor: Visual Ribbon Editor (1.3.1002.3): Visual Ribbon Editor 1.3.1002.3 What's New: Multi-language support for Labels/Tooltips for custom buttons and groups Support for base language other than English (1033) Connect dialog will not require organization name for ADFS / IFD connections Automatic creation of missing labels for all provisioned languages Minor connection issues fixed Notes: Before saving the ribbon to CRM server, editor will check Ribbon XML for any missing <Title> elements inside existing <LocLabel> elements...New Projectsamplifi: This project is still under construction. We will add more information here as soon as it is available.autoclubpigue: Proyecto para el auto club de piguecoiffeurprj: coiffeurprjerutufym: erutufym is gnol eht gge.Express AOP: A .NET AOP ToolsFile Slurpee: The purpouse of this application is to help security professionals during their penetration tests. Given a configuration this application will scour the target Guardian - Google Authenticator: Guardian is a windows client application for Google Authenticator - a software based two-factor authentication token developed by Google.ManagedCuda Galaxy Simulator: This project is a test of ManagedCuda and graphics interop to OpenTK to simulate a simple galaxy on the GPU.mostafanote: ????? ???? ??????? ?? ???? ?? ?? ?? ? ?? ??????? ?? ??????? ??? ?? ??? ?? ?? ???????? ??????? ??? ??? ?? ???? ?????? NXT Controller: A simple controller for the LEGO Mindstorms NXTPowerShell Security: PoshSec is short for PowerShell security, a module provided to allow PowerShell users testing, analysis and reporting on Window securityRevenant Raiders - Sunstrider: Tool to provide information about Revenant Raiders - Sunstrider.Run: animal runSharedDeploy: Simple ASP.MVC app , that use 2 types of view : mobile and desktop. In core WebApi, jQuery, jQuery.mobileSkyCoffee: Cafeteria ApplicationSOSA Analysis Module: Analysis program for data from SOSA psychological experiment software.SQL Connector: SQL Connector is a .DLL file that make it easy to comunicate with SQL Server Works in : Windows Desktop Applications ASP.Net Web (MVC - WEB Services) Windows cSQL Job Scripter: SQL Job Scripter is a command line utility that produces scripts of SQL Agent jobs. It will script either to a single file or to one file per job. SQL Server Watcher: A tool for collecting and monitoring information about sql server.Team Build Inspector: An add-in for Visual Studio Team Explorer that monitors the status of build definitions by its latest build, latest good build & underlying source code status.TED Talk Download Manager: "TED Talk Download Manager" provides a central point in which to download multiple TED talks, while keeping track of any talk previously downloaded.Temp project mycollection: My collection temporary projectUnreal Unit Converter: A Simple UDK <-> 3DS Max <-> Meters Unit Converter - with some other stuff.Watermelon Site: This Site is The site of Watermelon Inc. In This Site: Downloads News about Watermelon And more... WiX Extended Bootstrapper Application: An extended WiX bootstrapper Application based on the WiX standard bootstrapper application.Wrox NHibernate with ASP.NET Problem-Design-Solution -C# version: sample code of Wrox NHibernate with ASP.NET Problem-Design-Solution (http://nhibernateasp.codeplex.com/) in C# which is done as a practice

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  • Why nautilus quicklist is not working?

    - by jasmines
    None of my bookmarks (Documents, Pictures, Download, Dropbox, Ubuntu One, Music, Public) are correctly shown but they won't open if I right click on the Home icon and select them. The only ones who work are Home and Open A New Window. I've read similar questions (http://askubuntu.com/questions/184504/unity-home-quicklist-not-working-when-nautilus-is-closed and unity home quicklist not working) but my problem seems different... Anyway I can't solve with the suggested workarounds. $ ls ~ Audiobooks Dropbox Modelli Pubblici Video Backup dvdrip-data Musica Scaricati VirtualBox VMs deja-dup grive Pictures - GT-I9100 Scrivania virtual-drives Documenti Immagini Podcasts Ubuntu One Vuze Downloads $ cat /usr/share/applications/nautilus.desktop [Desktop Entry] Name=Files Comment=Access and organize files Exec=nautilus %U Icon=system-file-manager Terminal=false Type=Application StartupNotify=true OnlyShowIn=GNOME;Unity; Categories=GNOME;GTK;Utility;Core; MimeType=inode/directory;application/x-gnome-saved-search; X-GNOME-Bugzilla-Bugzilla=GNOME X-GNOME-Bugzilla-Product=nautilus X-GNOME-Bugzilla-Component=general X-GNOME-Bugzilla-Version=3.4.2 Actions=Window; X-Ubuntu-Gettext-Domain=nautilus [Desktop Action Window] Name=Open a New Window Exec=nautilus OnlyShowIn=Unity;

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  • Calculating 3d rotation around random axis

    - by mitim
    This is actually a solved problem, but I want to understand why my original method didn't work (hoping someone with more knowledge can explain). (Keep in mind, I've not very experienced in 3d programming, having only played with the very basic for a little bit...nor do I have a lot of mathematical experience in this area). I wanted to animate a point rotating around another point at a random axis, say a 45 degrees along the y axis (think of an electron around a nucleus). I know how to rotate using the transform matrix along the X, Y and Z axis, but not an arbitrary (45 degree) axis. Eventually after some research I found a suggestion: Rotate the point by -45 degrees around the Z so that it is aligned. Then rotate by some increment along the Y axis, then rotate it back +45 degrees for every frame tick. While this certainly worked, I felt that it seemed to be more work then needed (too many method calls, math, etc) and would probably be pretty slow at runtime with many points to deal with. I thought maybe it was possible to combine all the rotation matrixes involve into 1 rotation matrix and use that as a single operation. Something like: [ cos(-45) -sin(-45) 0] [ sin(-45) cos(-45) 0] rotate by -45 along Z [ 0 0 1] multiply by [ cos(2) 0 -sin(2)] [ 0 1 0 ] rotate by 2 degrees (my increment) along Y [ sin(2) 0 cos(2)] then multiply that result by (in that order) [ cos(45) -sin(45) 0] [ sin(45) cos(45) 0] rotate by 45 along Z [ 0 0 1] I get 1 mess of a matrix of numbers (since I was working with unknowns and 2 angles), but I felt like it should work. It did not and I found a solution on wiki using a different matirx, but that is something else. I'm not sure if maybe I made an error in multiplying, but my question is: this is actually a viable way to solve the problem, to take all the separate transformations, combine them via multiplying, then use that or not?

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  • Amazon AMIs and Oracle VM templates

    - by llaszews
    I have worked with Oracle VM templates and most recently with Amazon Machine Images (AMI). The similarities in the functionality and capabilities they provide are striking. Just take a look a the definitions: An Amazon Machine Image (AMI) is a special type of pre-configured operating system and virtual application software which is used to create a virtual machine within the Amazon Elastic Compute Cloud (EC2). It serves as the basic unit of deployment for services delivered using EC2. AWS AMIs Oracle VM Templates provide an innovative approach to deploying a fully configured software stack by offering pre-installed and pre-configured software images. Use of Oracle VM Templates eliminates the installation and configuration costs, and reduces the ongoing maintenance costs helping organizations achieve faster time to market and lower cost of operations. Oracle VM Templates Other things they have in common: 1. Both have 35 Oracle images or templates: AWS AMI pre-built images Oracle pre-built VM Templates 2. Both allow to build your own images or templates: A. OVM template builder - OVM Template Builder - Oracle VM Template Builder, an open source, graphical utility that makes it easy to use Oracle Enterprise Linux “Just enough OS” (JeOS)–based scripts for developing pre-packaged virtual machines for Oracle VM. B. AMI 'builder' - AMI builder However, AWS has the added feature/benefit of adding your own AMI to the AWS AMI catalog: AMI - Adding to the AWS AMI catalog Another plus with AWS and AMI is there are hundreds of MySQL AMIs (AWS MySQL AMIs ). A benefit of Oracle VM templates is they can run on any public or private cloud environment, not just AWS EC2. However, with Oracle VM templates they first need to be images as AMIs before they can run in the AWS cloud.

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  • OUM is Flexible and Scalable

    - by user535886
    Flexible and Scalable Traditionally, projects have been focused on satisfying the contents of a requirements document or rigorously conforming to an existing set of work products. Often, especially where iterative and incremental techniques have not been employed, these requirements may be inaccurate, the previous deliverables may be flawed, or the business needs may have changed since the start of the project. Fitness for business purpose, derived from the Dynamic Systems Development Method (DSDM) framework, refers to the focus of delivering necessary functionality within a required timebox. The solution can be more rigorously engineered later, if such an approach is acceptable. Our collective experience shows that applying fit-for-purpose criteria, rather than tight adherence to requirements specifications, results in an information system that more closely meets the needs of the business. In OUM, this principle is extended to refer to the execution of the method processes themselves. Project managers and practitioners are encouraged to scale OUM to be fit-for-purpose for a given situation. It is rarely appropriate to execute every activity within OUM. OUM provides guidance for determining the core set of activities to be executed, the level of detail targeted in those activities and their associated tasks, and the frequency and type of end user deliverables. The project workplan should be developed from this core. The plan should then be scaled up, rather than tailored down, to the level of discipline appropriate to the identified risks and requirements. Even at the task level, models and work products should be completed only to the level of detail required for them to be fit-for-purpose within the current iteration or, at the project level, to suit the business needs of the enterprise and to meet the contractual obligations that govern the project. OUM provides well defined templates for many of its tasks. Use of these templates is optional as determined by the context of the project. Work products can easily be a model in a repository, a prototype, a checklist, a set of application code, or, in situations where a high degree of agility is warranted, simply the tacit knowledge contained in the brain of an analyst or practitioner. For further reading on agility, see Balancing Agility and Discipline: A guide fro the Perplexed.

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  • Collision Detection with SAT: False Collision for Diagonal Movement Towards Vertical Tile-Walls?

    - by Macks
    Edit: Problem solved! Big thanks to Jonathan who pointed me in the right direction. Sean describes the method I used in a different thread. Also big thanks to him! :) Here is how I solved my problem: If a collision is registered by my SAT-method, only fire the collision-event on my character if there are no neighbouring solid tiles in the direction of the returned minimum translation vector. I'm developing my first tile-based 2D-game with Javascript. To learn the basics, I decided to write my own "game engine". I have successfully implemented collision detection using the separating axis theorem, but I've run into a problem that I can't quite wrap my head around. If I press the [up] and [left] arrow-keys simultaneously, my character moves diagonally towards the upper left. If he hits a horizontal wall, he'll just keep moving in x-direction. The same goes for [up] and [left] as well as downward-diagonal movements, it works as intended: http://i.stack.imgur.com/aiZjI.png Diagonal movement works fine for horizontal walls, for both left and right-movement However: this does not work for vertical walls. Instead of keeping movement in y-direction, he'll just stop as soon as he "enters" a new tile on the y-axis. So for some reason SAT thinks my character is colliding vertically with tiles from vertical walls: http://i.stack.imgur.com/XBEKR.png My character stops because he thinks that he is colliding vertically with tiles from the wall on the right. This only occurs, when: Moving into top-right direction towards the right wall Moving into top-left direction towards the left wall Bottom-right and bottom-left movement work: the character keeps moving in y-direction as intended. Is this inherited from the way SAT works or is there a problem with my implementation? What can I do to solve my problem? Oh yeah, my character is displayed as a circle but he's actually a rectangular polygon for the collision detection. Thank you very much for your help.

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  • Augmenting functionality of subclasses without code duplication in C++

    - by Rob W
    I have to add common functionality to some classes that share the same superclass, preferably without bloating the superclass. The simplified inheritance chain looks like this: Element -> HTMLElement -> HTMLAnchorElement Element -> SVGElement -> SVGAlement The default doSomething() method on Element is no-op by default, but there are some subclasses that need an actual implementation that requires some extra overridden methods and instance members. I cannot put a full implementation of doSomething() in Element because 1) it is only relevant for some of the subclasses, 2) its implementation has a performance impact and 3) it depends on a method that could be overridden by a class in the inheritance chain between the superclass and a subclass, e.g. SVGElement in my example. Especially because of the third point, I wanted to solve the problem using a template class, as follows (it is a kind of decorator for classes): struct Element { virtual void doSomething() {} }; // T should be an instance of Element template<class T> struct AugmentedElement : public T { // doSomething is expensive and uses T virtual void doSomething() override {} // Used by doSomething virtual bool shouldDoSomething() = 0; }; class SVGElement : public Element { /* ... */ }; class SVGAElement : public AugmentedElement<SVGElement> { // some non-trivial check bool shouldDoSomething() { /* ... */ return true; } }; // Similarly for HTMLAElement and others I looked around (in the existing (huge) codebase and on the internet), but didn't find any similar code snippets, let alone an evaluation of the effectiveness and pitfalls of this approach. Is my design the right way to go, or is there a better way to add common functionality to some subclasses of a given superclass?

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  • API Class with intensive network requests

    - by Marco Acierno
    I'm working an API which works as "intermediary" between a REST API and the developer. In this way, when the programmer do something like this: User user = client.getUser(nickname); it will execute a network request to download from the service the data about the user and then the programmer can use the data by doing things like user.getLocation(); user.getDisplayName(); and so on. Now there are some methods like getFollowers() which execute another network request and i could do it in two ways: Download all the data in the getUser method (and not only the most important) but in this way the request time could be very long since it should execute the request to various urls Download the data when the user calls the method, it looks like the best way and to improve it i could cache the result so the next call to getFollowers returns immediately with the data already download instead of execute again the request. What is the best way? And i should let methods like getUser and getFollowers stop the code execution until the data is ready or i should implement a callback so when the data is ready the callback gets fired? (this looks like Javascript)

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  • Applications: The mathematics of movement, Part 1

    - by TechTwaddle
    Before you continue reading this post, a suggestion; if you haven’t read “Programming Windows Phone 7 Series” by Charles Petzold, go read it. Now. If you find 150+ pages a little too long, at least go through Chapter 5, Principles of Movement, especially the section “A Brief Review of Vectors”. This post is largely inspired from this chapter. At this point I assume you know what vectors are, how they are represented using the pair (x, y), what a unit vector is, and given a vector how you would normalize the vector to get a unit vector. Our task in this post is simple, a marble is drawn at a point on the screen, the user clicks at a random point on the device, say (destX, destY), and our program makes the marble move towards that point and stop when it is reached. The tricky part of this task is the word “towards”, it adds a direction to our problem. Making a marble bounce around the screen is simple, all you have to do is keep incrementing the X and Y co-ordinates by a certain amount and handle the boundary conditions. Here, however, we need to find out exactly how to increment the X and Y values, so that the marble appears to move towards the point where the user clicked. And this is where vectors can be so helpful. The code I’ll show you here is not ideal, we’ll be working with C# on Windows Mobile 6.x, so there is no built-in vector class that I can use, though I could have written one and done all the math inside the class. I think it is trivial to the actual problem that we are trying to solve and can be done pretty easily once you know what’s going on behind the scenes. In other words, this is an excuse for me being lazy. The first approach, uses the function Atan2() to solve the “towards” part of the problem. Atan2() takes a point (x, y) as input, Atan2(y, x), note that y goes first, and then it returns an angle in radians. What angle you ask. Imagine a line from the origin (0, 0), to the point (x, y). The angle which Atan2 returns is the angle the positive X-axis makes with that line, measured clockwise. The figure below makes it clear, wiki has good details about Atan2(), give it a read. The pair (x, y) also denotes a vector. A vector whose magnitude is the length of that line, which is Sqrt(x*x + y*y), and a direction ?, as measured from positive X axis clockwise. If you’ve read that chapter from Charles Petzold’s book, this much should be clear. Now Sine and Cosine of the angle ? are special. Cosine(?) divides x by the vectors length (adjacent by hypotenuse), thus giving us a unit vector along the X direction. And Sine(?) divides y by the vectors length (opposite by hypotenuse), thus giving us a unit vector along the Y direction. Therefore the vector represented by the pair (cos(?), sin(?)), is the unit vector (or normalization) of the vector (x, y). This unit vector has a length of 1 (remember sin2(?) + cos2(?) = 1 ?), and a direction which is the same as vector (x, y). Now if I multiply this unit vector by some amount, then I will always get a point which is a certain distance away from the origin, but, more importantly, the point will always be on that line. For example, if I multiply the unit vector with the length of the line, I get the point (x, y). Thus, all we have to do to move the marble towards our destination point, is to multiply the unit vector by a certain amount each time and draw the marble, and the marble will magically move towards the click point. Now time for some code. The application, uses a timer based frame draw method to draw the marble on the screen. The timer is disabled initially and whenever the user clicks on the screen, the timer is enabled. The callback function for the timer follows the standard Update and Draw cycle. private double totLenToTravelSqrd = 0; private double startPosX = 0, startPosY = 0; private double destX = 0, destY = 0; private void Form1_MouseUp(object sender, MouseEventArgs e) {     destX = e.X;     destY = e.Y;     double x = marble1.x - destX;     double y = marble1.y - destY;     //calculate the total length to be travelled     totLenToTravelSqrd = x * x + y * y;     //store the start position of the marble     startPosX = marble1.x;     startPosY = marble1.y;     timer1.Enabled = true; } private void timer1_Tick(object sender, EventArgs e) {     UpdatePosition();     DrawMarble(); } Form1_MouseUp() method is called when ever the user touches and releases the screen. In this function we save the click point in destX and destY, this is the destination point for the marble and we also enable the timer. We store a few more values which we will use in the UpdatePosition() method to detect when the marble has reached the destination and stop the timer. So we store the start position of the marble and the square of the total length to be travelled. I’ll leave out the term ‘sqrd’ when speaking of lengths from now on. The time out interval of the timer is set to 40ms, thus giving us a frame rate of about ~25fps. In the timer callback, we update the marble position and draw the marble. We know what DrawMarble() does, so here, we’ll only look at how UpdatePosition() is implemented; private void UpdatePosition() {     //the vector (x, y)     double x = destX - marble1.x;     double y = destY - marble1.y;     double incrX=0, incrY=0;     double distanceSqrd=0;     double speed = 6;     //distance between destination and current position, before updating marble position     distanceSqrd = x * x + y * y;     double angle = Math.Atan2(y, x);     //Cos and Sin give us the unit vector, 6 is the value we use to magnify the unit vector along the same direction     incrX = speed * Math.Cos(angle);     incrY = speed * Math.Sin(angle);     marble1.x += incrX;     marble1.y += incrY;     //check for bounds     if ((int)marble1.x < MinX + marbleWidth / 2)     {         marble1.x = MinX + marbleWidth / 2;     }     else if ((int)marble1.x > (MaxX - marbleWidth / 2))     {         marble1.x = MaxX - marbleWidth / 2;     }     if ((int)marble1.y < MinY + marbleHeight / 2)     {         marble1.y = MinY + marbleHeight / 2;     }     else if ((int)marble1.y > (MaxY - marbleHeight / 2))     {         marble1.y = MaxY - marbleHeight / 2;     }     //distance between destination and current point, after updating marble position     x = destX - marble1.x;     y = destY - marble1.y;     double newDistanceSqrd = x * x + y * y;     //length from start point to current marble position     x = startPosX - (marble1.x);     y = startPosY - (marble1.y);     double lenTraveledSqrd = x * x + y * y;     //check for end conditions     if ((int)lenTraveledSqrd >= (int)totLenToTravelSqrd)     {         System.Console.WriteLine("Stopping because destination reached");         timer1.Enabled = false;     }     else if (Math.Abs((int)distanceSqrd - (int)newDistanceSqrd) < 4)     {         System.Console.WriteLine("Stopping because no change in Old and New position");         timer1.Enabled = false;     } } Ok, so in this function, first we subtract the current marble position from the destination point to give us a vector. The first three lines of the function construct this vector (x, y). The vector (x, y) has the same length as the line from (marble1.x, marble1.y) to (destX, destY) and is in the direction pointing from (marble1.x, marble1.y) to (destX, destY). Note that marble1.x and marble1.y denote the center point of the marble. Then we use Atan2() to get the angle which this vector makes with the positive X axis and use Cosine() and Sine() of that angle to get the unit vector along that same direction. We multiply this unit vector with 6, to get the values which the position of the marble should be incremented by. This variable, speed, can be experimented with and determines how fast the marble moves towards the destination. After this, we check for bounds to make sure that the marble stays within the screen limits and finally we check for the end condition and stop the timer. The end condition has two parts to it. The first case is the normal case, where the user clicks well inside the screen. Here, we stop when the total length travelled by the marble is greater than or equal to the total length to be travelled. Simple enough. The second case is when the user clicks on the very corners of the screen. Like I said before, the values marble1.x and marble1.y denote the center point of the marble. When the user clicks on the corner, the marble moves towards the point, and after some time tries to go outside of the screen, this is when the bounds checking comes into play and corrects the marble position so that the marble stays inside the screen. In this case the marble will never travel a distance of totLenToTravelSqrd, because of the correction is its position. So here we detect the end condition when there is not much change in marbles position. I use the value 4 in the second condition above. After experimenting with a few values, 4 seemed to work okay. There is a small thing missing in the code above. In the normal case, case 1, when the update method runs for the last time, marble position over shoots the destination point. This happens because the position is incremented in steps (which are not small enough), so in this case too, we should have corrected the marble position, so that the center point of the marble sits exactly on top of the destination point. I’ll add this later and update the post. This has been a pretty long post already, so I’ll leave you with a video of how this program looks while running. Notice in the video that the marble moves like a bot, without any grace what so ever. And that is because the speed of the marble is fixed at 6. In the next post we will see how to make the marble move a little more elegantly. And also, if Atan2(), Sine() and Cosine() are a little too much to digest, we’ll see how to achieve the same effect without using them, in the next to next post maybe. Ciao!

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  • The best way to have a pointer to several methods - critique requested

    - by user827992
    I'm starting with a short introduction of what i know from the C language: a pointer is a type that stores an adress or a NULL the * operator reads the left value of the variable on its right and use this value as address and reads the value of the variable at that address the & operator generate a pointer to the variable on its right so i was thinking that in C++ the pointers can work this way too, but i was wrong, to generate a pointer to a static method i have to do this: #include <iostream> class Foo{ public: static void dummy(void){ std::cout << "I'm dummy" << std::endl; }; }; int main(){ void (*p)(); p = Foo::dummy; // step 1 p(); p = &(Foo::dummy); // step 2 p(); p = Foo; // step 3 p->dummy(); return(0); } now i have several questions: why step 1 works why step 2 works too, looks like a "pointer to pointer" for p to me, very different from step 1 why step 3 is the only one that doesn't work and is the only one that makes some sort of sense to me, honestly how can i write an array of pointers or a pointer to pointers structure to store methods ( static or non-static from real objects ) what is the best syntax and coding style for generating a pointer to a method?

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  • Unable to mount an LVM Hard-drive after upgrade

    - by Bruce Staples
    I imagine this is a basic gotcha ... but I can't see it. I have a system with 2(physical) harddrives. The boot system (/dev/sda) was running 10.04 & the second drive (/dev/sdb) was just a mounted filesystem. I did a clean load of Ubuntu 12.04 overwriting /dev/sda (not an upgrade) & now cannot mount the second drive. so I do not know what to enter it into the fstab ... I had expected to use: /dev/sdb /tera ext4 defaults 0 2 But even manual mounting fails (I also have tried various "-t" options on the off chance!) sudo mount -t ext4 /dev/sdb1 /tera mount: wrong fs type, bad option, bad superblock on /dev/sdb1, missing codepage or helper program, or other error In some cases useful info is found in syslog - try dmesg | tail or so Output from disk queries indicate that it is a Linux LVM & a healthy disk still. sudo lshw -C disk *-disk:0 description: ATA Disk product: WDC WD5000AACS-0 vendor: Western Digital physical id: 0 bus info: scsi@2:0.0.0 logical name: /dev/sda version: 01.0 serial: WD-WCASU1401098 size: 465GiB (500GB) capabilities: partitioned partitioned:dos configuration: ansiversion=5 signature=00015a55 *-disk:1 description: ATA Disk product: WDC WD10EADS-00L vendor: Western Digital physical id: 1 bus info: scsi@3:0.0.0 logical name: /dev/sdb version: 01.0 serial: WD-WCAU47836304 size: 931GiB (1TB) capabilities: partitioned partitioned:dos configuration: ansiversion=5 sudo fdisk -l Disk /dev/sda: 500.1 GB, 500106780160 bytes 255 heads, 63 sectors/track, 60801 cylinders, total 976771055 sectors Units = sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x00015a55 Device Boot Start End Blocks Id System /dev/sda1 * 2048 972580863 486289408 83 Linux /dev/sda2 972582910 976769023 2093057 5 Extended /dev/sda5 972582912 976769023 2093056 82 Linux swap / Solaris Disk /dev/sdb: 1000.2 GB, 1000204886016 bytes 255 heads, 63 sectors/track, 121601 cylinders, total 1953525168 sectors Units = sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x00000000 Device Boot Start End Blocks Id System /dev/sdb1 1 1953525167 976762583+ 8e Linux LVM LVM doesn't appear to be an option for mount or fstab. ... and here's a Smart data Screenshot from Disk Utility.

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  • How to properly structure a project in winform?

    - by user850010
    A while ago I started to create a winform application and at that time it was small and I did not give any thought of how to structure the project. Since then I added additional features as I needed and the project folder is getting bigger and bigger and now I think it is time to structure the project in some way, but I am not sure what is the proper way, so I have few questions. How to properly restructure the project folder? At the moment I am thinking of something like this: Create Folder for Forms Create Folder for Utility classes Create Folder for Classes that contain only data What is the naming convention when adding classes? Should I also rename classes so that their functionality can be identified by just looking at their name? For example renaming all forms classes, so that their name ends with Form. Or is this not necessary if special folders for them are created? What to do, so that not all the code for main form ends up in Form1.cs Another problem I encountered is that as the main form is getting more massive with each feature I add, the code file (Form1.cs) is getting really big. I have for example a TabControl and each tab has bunch of controls and all the code ended up in Form1.cs. How to avoid this? Also, Do you know any articles or books that deal with these problems?

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  • Sprite transparency not effected libGDX

    - by Aon GoltzCrank
    I am making a game using libGDX and Tween Universal Engine. My problem is as follows: I have 2 screens so fars, a splash screen with the logo, and a second one which is the main menu. In the splash screen I use a SpriteBatch and a Sprite with the Texture of the image I want (which goes through some scaling.) Now I use the Tween engine, along with a created SpriteAccessor to control the alpha of the sprite. I fade the picture in, then fade it out, then change it to the next screen. In the next screen I have a single sprite, and a single, 3 slot, sprite array. In this screen I also use the tween engine, I fade the single sprite into the screen (it's the background image) then I try to, using the same method, (Tween.to) to change the alpah of the sprite array (each sprite by itself.), I first set it to 0 using Tween.set, then using the method I change it. This didn't work, after some tests I tried setting the alpha of a single sprite from the array to 0, and that didn't work. It's like the program is ignoring the alpha value, I even printed out the alpha value, it saying 0, but the sprite is visible. How can I fix this, or why might it be caused?

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  • Making files generally available on Linux system (when security is relatively unimportant)?

    - by Ole Thomsen Buus
    Hi, I am using Ubuntu 9.10 on a stationary PC. I have a secondary 1 TB harddrive with a single big logical partition (currently formatted as ext4). It is mounted as /usr3 with options user, exec in /etc/fstab. I am doing highspeed imaging experiments. Well, only 260fps, but that still creates many individual files since each frames is saved as one png-file. The stationary is not used by anyone other than me which is why the default security model posed by ubuntu is not necessary. What is the best way to make the entire contents of /usr3 generally available on all systems. In case I need to move the harddrive to another Ubuntu 9.x or 10.x machine? When grabbing image with the firewire camera I use a selfmade grabbing software-utility (console based) in sudo-mode. This creates all files with root as owner and group. I am logged in as user otb and usually I do the following when having to make files generally available to otb: sudo chown otb -R * sudo chgrp otb -R * sudo chmod a=rwx -R * This takes some time since the disk now contains individual ~200000 files. After this, how would linux behave if I moved the harddrive to another system where the user otb is also available? Would the files still be accessible without sudo use?

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  • Is there a way to use the facebook sdk with libgdx?

    - by Rudy_TM
    I have tried to use the facebook sdk in libgdx with callbacks, but it never enters the authetication listeners, so the user never is logged in, it permits the authorization for the facebook app but it never implements the authentication interfaces :( Is there a way to use it? public MyFbClass() { facebook = new Facebook(APPID); mAsyncRunner = new AsyncFacebookRunner(facebook); SessionStore.restore(facebook, this); FB.init(this, 0, facebook, this.permissions); } ///Method for init the permissions and my listener for authetication public void init(final Activity activity, final Facebook fb,final String[] permissions) { mActivity = activity; this.fb = fb; mPermissions = permissions; mHandler = new Handler(); async = new AsyncFacebookRunner(mFb); params = new Bundle(); SessionEvents.addAuthListener(auth); } ///I call the authetication process, I call it with a callback from libgdx public void facebookAction() { // TODO Auto-generated method stub fb.authenticate(); } ///It only allow the app permission, it doesnt register the events public void authenticate() { if (mFb.isSessionValid()) { SessionEvents.onLogoutBegin(); AsyncFacebookRunner asyncRunner = new AsyncFacebookRunner(mFb); asyncRunner.logout(getContext(), new LogoutRequestListener()); //SessionStore.save(this.mFb, getContext()); } else { mFb.authorize(mActivity, mPermissions,0 , new DialogListener()); } } public class SessionListener implements AuthListener, LogoutListener { @Override public void onAuthSucceed() { SessionStore.save(mFb, getContext()); } @Override public void onAuthFail(String error) { } @Override public void onLogoutBegin() { } @Override public void onLogoutFinish() { SessionStore.clear(getContext()); } } DialogListener() { @Override public void onComplete(Bundle values) { SessionEvents.onLoginSuccess(); } @Override public void onFacebookError(FacebookError error) { SessionEvents.onLoginError(error.getMessage()); } @Override public void onError(DialogError error) { SessionEvents.onLoginError(error.getMessage()); } @Override public void onCancel() { SessionEvents.onLoginError("Action Canceled"); } }

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  • Ubuntu 12.10: Installing proprietary Nvidia driver causes freeze at boot

    - by Greg
    Ok, so I just installed Ubuntu on my laptop, and I immediately encountered an issue: the HDMI audio output won't work. Yes, I know about the sound settings thing where you have to select the HDMI option, but even when it's selected I get no sound out of the TV I'm hooking it up to. This is a dealbreaker for me, because my laptop speakers are terrible, it's one of the big reasons I use my TV monitor. So I decided to work on solving the problem by upgrading my Nvidia drivers. I switched to one of the propriety drivers offered in that software updating utility that comes with the OS, the one option that said (tested). Viola, sound over the HDMI is now working. Unfortunately, this now brings me to my next problem: when I reboot Ubuntu with this or any other proprietary driver installed, it freezes when it tries to load my desktop. As in I can see my wallpaper, but no icons or options of any kind. The system is totally frozen, and gives me one of those "we've experienced an error, do you want to report it messages." So there's my bind. I need HDMI audio out, that's a total dealbreaker for me, but installing the drivers that give me that capability crash the system. Does anyone have any idea what's causing this

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  • JSCompress fails to compress my js file - why?

    - by Renso
    Issue: You use the online compression utility jscompress.com to compress your js file but it fails with an error. Why this may be happening and how to fix it. Possible causes: Apparently not using open and closing curly brackets in an IF statement would cause this. Well turns out this is not the case. Look at the following example and see if you can figure out what the issue is :-)   function SetupDeliveredVPRecontactNotes($item, id) {     var theData;     $.ajax({         data: { deliveredVPId: id },         url: $('#ajaxGetDeliveredVPRecontactNotesUrl').val(),         type: "GET",         async: false,         dataType: "html",         success: function(data, result) {             $item.empty();             var input = '<textarea class="recontactNote" rows="4" name="DeliveredVPRecontactNotes_' + id + '" id="DeliveredVPRecontactNotes_' + id + '" cols="115">' + data + '</textarea>';             $item.append(input);             theData = data;         },         error: function(XMLHttpRequest, textStatus, errorThrown) {             $item.empty();             alert("An error occurred: The operation to retrieve the DeliveredVP's Recontact Notes has failed");         }     });                  //ajax     return theData; }     Solution: The name of the method/function is the same as the message in the ALERT message when the spaces are removed: " DeliveredVP Recontact Notes" becomes " DeliveredVPRecontactNotes" and mathes that of the function. So I changed it to " DeliveredVP's Recontact Notes"

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  • How would you TDD the functionality of getting the corresponding process of a running windows service?

    - by Matt Spinelli
    Purpose Over the last year or more I've been learning unit testing via books I've read recently like The Art of Unit Testing, Working Effectively with Legacy Code, and others. I've also been using unit tests, mocking frameworks, and the like, periodically at work and definitely see the value. However, I'm still having a hard time wrapping my mind around TDD (as opposed to TAD) when the situation calls for code that is gong to mostly use external API calls. Problem to solve Get the process associated with a windows service using the service name. example: Function GetProcess(ByVal serviceName As String) As Process Rules Show each major iteration in production & test code using TDD No need to see any other code or configuration that is required to get things to run. Just curious about the interfaces, concrete classes, and test methods. C# or VB.NET Must use the .Net framework regarding services/processes (i.e. System.Diagnostics.Process) Test Frameworks: Nunit or MSTest Isolation Frameworks: Moq, Rhino Mock, or Microsoft Moles Must write true unit tests (no integration tests) Additional notes As far as I can tell there are two approaches design wise. Use an Inversion of Control approach along with using the Adapter and/or Facade patterns to wrap the underlying .net framework objects dealing with processes and services. Keep the .net framework code in the class containing the Get Process method and use code detouring (interception) via Microsoft Moles to isolate the hard dependencies from the method under test.

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  • Updating an ADF Web Service Data Control When Service Structure or Location Change

    - by Shay Shmeltzer
    The web service data control in Oracle ADF gives you a simplified approach to consuming services in ADF applications, and now with ADF Mobile the usage of this service seems to be growing. A frequent question we get is what happens if the service that I'm consuming changes - how do I update my data control? Well, first we should mention that if you do a good design of your application before you actually code - then things like Web service method signature shouldn't change. The signature is the contract between the publisher and the consumer, and contracts shouldn't be broken. But in reality things do change during development stages, so here is how you can update both method signatures and service location with the Web service data control: After watching this video you might be tempted to not copy the WSDLs to your project - which lets you use the right click update on a data control. However there is a reason why the copy is on by default, it reduces network traffic when you are actually running your application since ADF doesn't need to go to the server to find out the service structure. So for runtime performance, you probably should keep the WSDL local.  I encourage you to further look into both the connections.xml file where your service location is saved, and the datacontrols.dcx file where its definition is kept to get an even deeper understanding of how ADF works underneath the declarative layers.

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  • Slow USB 3.0 speeds

    - by Cygnus X
    Long time forum forager, first time poster. I bought a Toshiba 500 GB usb 3.0 hard drive last week and instantly ran home to see how fast I could push it. On my desktop (that I built) I was able to get 200 MB/sec. On my laptop (MSI FX something or other), which I dual boot Windows 7/Ubuntu 11.10, I was able to get about 120 MB/sec on Windows, but on Ubuntu, i get about 25 MB/sec. lsusb shows: Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub Bus 002 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub Bus 003 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub Bus 004 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub Bus 001 Device 002: ID 8087:0020 Intel Corp. Integrated Rate Matching Hub Bus 002 Device 002: ID 8087:0020 Intel Corp. Integrated Rate Matching Hub Bus 001 Device 003: ID 0bda:0139 Realtek Semiconductor Corp. Bus 002 Device 003: ID 1532:0015 Razer USA, Ltd Bus 004 Device 002: ID 0480:a007 Toshiba America Info. Systems, Inc. lspci -vvv shows that the USB 3.0 host controller is using the kernel driver in use is xhci_hcd. dmesg |grep usb shows: [ 1815.455368] usb 4-1: new SuperSpeed USB device number 2 using xhci_hcd [ 1815.475459] scsi7 : usb-storage 4-1:1.0 The built in disk utility says its connected via usb at 705 MB/s, but that's not what it reports when I transfer files over to it. Not really sure what to do at this point. Any help would be very nice, thank you.

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  • Platform game collisions with Block

    - by Sri Harsha Chilakapati
    I am trying to create a platform game and doing wrong collision detection with the blocks. Here's my code // Variables GTimer jump = new GTimer(1000); boolean onground = true; // The update method public void update(long elapsedTime){ MapView.follow(this); // Add the gravity if (!onground && !jump.active){ setVelocityY(4); } // Jumping if (isPressed(VK_SPACE) && onground){ jump.start(); setVelocityY(-4); onground = false; } if (jump.action(elapsedTime)){ // jump expired jump.stop(); } // Horizontal movement setVelocityX(0); if (isPressed(VK_LEFT)){ setVelocityX(-4); } if (isPressed(VK_RIGHT)){ setVelocityX(4); } } // The collision method public void collision(GObject other){ if (other instanceof Block){ // Determine the horizontal distance between centers float h_dist = Math.abs((other.getX() + other.getWidth()/2) - (getX() + getWidth()/2)); // Now the vertical distance float v_dist = Math.abs((other.getY() + other.getHeight()/2) - (getY() + getHeight()/2)); // If h_dist > v_dist horizontal collision else vertical collision if (h_dist > v_dist){ // Are we moving right? if (getX()<other.getX()){ setX(other.getX()-getWidth()); } // Are we moving left? else if (getX()>other.getX()){ setX(other.getX()+other.getWidth()); } } else { // Are we moving up? if (jump.active){ jump.stop(); } // We are moving down else { setY(other.getY()-getHeight()); setVelocityY(0); onground = true; } } } } The problem is that the object jumps well but does not fall when moved out of platform. Here's an image describing the problem. I know I'm not checking underneath the object but I don't know how. The map is a list of objects and should I have to iterate over all the objects??? Thanks

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  • Tackling thin content on an images gallery

    - by Ted Wilmont
    We run an images gallery as part of our site, however we have over 8,000 images and every image has a separate HTML page of its own to display the image caption, related image and comments from users of the site. This seems to be a problem especially with the Google Panda update because these pages are technically "thin content". What would be the best way to tackle this? We'd love some feedback and advice regarding this scenario. We have a few options we thought of already but can't decide: We could noindex the separate image pages and loose any image search listings we have for the image in favour of removing these thin pages from the index. We could 301 all of the individual image pages back to the image category listing and anchor each image (e.g. #img2122) and include all of the comments and description on the category listing page itself. If we was to simply list all of the images and content on the category pages themself; what's the best method? We could add all of the content in the anchor tags and use jQuery to display them in a box when a user clicks on the image or we could use Ajax to retrieve the information. However, what's the best Ajax method for SEO? Any ideas, suggestions, tips or advice is greatly appreciated and thank you in advance for any given.

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  • Interview Questions in OOP

    - by Fero
    Hi all, I faced the below interview questions in OOP under PHP language. Kindly clear my clarifications regarding this. I am very confused. As i am a beginner to OOP i got too confused. Could anyone clarify these things clearly? Difference between Abstract class and interface. Interviewer : Let us consider abstract class contains three abstract methods such as a,b,c and interface contains three methods a,b,c. In this case these do the same functionality. Then why are going for abstract and why are we going for interface. Me : ? static keyword. Interviewer: We call static method without creating object by using scope resolution operator in PHP. As well as we can able to call concrete methods also. Then what is need of static keyword there? Me : .... final keyword. Interviewer: Give me any scenario of using final keyword. Me : For db connection related method Interviewer: Other than that? Me: ... Constructor. Interviewer: What is the use of constructor? Me : There is no need for object to access this. It will call automatically when the class calls. Interviewer: Other than that? Me : .... Thanks in advance...

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  • Converting raw data type to enumerated type

    - by Jim Lahman
    There are times when an enumerated type is preferred over using the raw data type.  An example of using a scheme is when we need to check the health of x-ray gauges in use on a production line.  Rather than using a scheme like 0, 1 and 2, we can use an enumerated type: 1: /// <summary> 2: /// POR Healthy status indicator 3: /// </summary> 4: /// <remarks>The healthy status is for each POR x-ray gauge; each has its own status.</remarks> 5: [Flags] 6: public enum POR_HEALTH : short 7: { 8: /// <summary> 9: /// POR1 healthy status indicator 10: /// </summary> 11: POR1 = 0, 12: /// <summary> 13: /// POR2 healthy status indicator 14: /// </summary> 15: POR2 = 1, 16: /// <summary> 17: /// Both POR1 and POR2 healthy status indicator 18: /// </summary> 19: BOTH = 2 20: } By using the [Flags] attribute, we are treating the enumerated type as a bit mask.  We can then use bitwise operations such as AND, OR, NOT etc. . Now, when we want to check the health of a specific gauge, we would rather use the name of the gauge than the numeric identity; it makes for better reading and programming practice. To translate the numeric identity to the enumerated value, we use the Parse method of Enum class: POR_HEALTH GaugeHealth = (POR_HEALTH) Enum.Parse(typeof(POR_HEALTH), XrayMsg.Gauge_ID.ToString()); The Parse method creates an instance of the enumerated type.  Now, we can use the name of the gauge rather than the numeric identity: 1: if (GaugeHealth == POR_HEALTH.POR1 || GaugeHealth == POR_HEALTH.BOTH) 2: { 3: XrayHealthyTag.Name = Properties.Settings.Default.POR1XRayHealthyTag; 4: } 5: else if (GaugeHealth == POR_HEALTH.POR2) 6: { 7: XrayHealthyTag.Name = Properties.Settings.Default.POR2XRayHealthyTag; 8: }

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  • On developing deep programming knowledge

    - by Robert Harvey
    Occasionally I see questions about edge cases and other weirdness on Stack Overflow that are easily answered by the likes of Jon Skeet and Eric Lippert, demonstrating a deep knowledge of the language and its many intricacies, like this one: You might think that in order to use a foreach loop, the collection you are iterating over must implement IEnumerable or IEnumerable<T>. But as it turns out, that is not actually a requirement. What is required is that the type of the collection must have a public method called GetEnumerator, and that must return some type that has a public property getter called Current and a public method MoveNext that returns a bool. If the compiler can determine that all of those requirements are met then the code is generated to use those methods. Only if those requirements are not met do we check to see if the object implements IEnumerable or IEnumerable<T>. That's cool stuff to know. I can understand why Eric knows this; he's on the compiler team, so he has to know. But what about those who demonstrate such deep knowledge who are not insiders? How do mere mortals (who are not on the C# compiler team) find out about stuff like this? Specifically, are there methods these folks use to systematically root out such knowledge, explore it and internalize it (make it their own)?

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