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  • How to change row color based on a single cell's value?

    - by flyfisher
    I have a spreadsheet where I have cell within a row that will contain specific text via data validation. So for instance a cell could contain the text "Due in 7 Days", "Past Due", or "Closed". I want the row color to change depending on the text that appears in the cell. So if the text "Past Due" appears in the cell I want that entire row to turn red, if "Due In 7 Days" appears the row should turn yellow, and if "Closed" the row would turn gray. How can I do that?

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  • Json object merge with unqiue id

    - by Hitu
    I have multiple json Objects json1 = [ {'category_id':1,'name':'test1' }, {'category_id':1,'name':'test2' }, {'category_id':1,'name':'test3' }, {'category_id':2,'name':'test2' }, {'category_id':3,'name':'test1' } ]; json2 = [{'category_id':1,'type':'test1'}]; json3 = [ {'category_id':1,'color':'black'}, {'category_id':2,'color':'black'}, {'category_id':3,'color':'white'} ]; I am expecting output like this final = [ {'category_id':1,'name':'test1','type':'test`','color':'black' }, {'category_id':1,'name':'test2','type':'test`','color':'black' }, {'category_id':1,'name':'test3','type':'test`','color':'black' }, {'category_id':2,'name':'test2','color':'black' }, {'category_id':3,'name':'test1','color':'white' } ]; As i have long json object. Looping is good idea or not ? Does there is any inbuilt function for doing the same.

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  • CSS: a:link vs just a (without the :link part)

    - by Rob
    So we're required to use the following order for CSS anchor pseudo-classes a:link { color: red } a:visited { color: blue } a:hover { color: yellow } a:active { color: lime } But my question is why bother with the a:link part? Rather, is there any advantage to the above (other than perhaps clarity) over: a { color:red; } /* notice no :link part */ a:visited { color: blue; } etc.,etc.

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  • Using rounded corners in modern websites with CSS3

    - by nikolaosk
    This is going to be the sixth post in a series of posts regarding HTML 5. You can find the other posts here , here, here , here and here.In this post I will provide a hands-on example on how to use rounded corners (rounded corners in CSS3) in your website. I think this is the feature that is most required in the new modern websites.Most websites look great with their lovely round panels and rounded corner tab style menus. We could achieve that effect earlier but we should resort to complex CSS rules and images. I will show you how to accomplish this great feature with the power of CSS 3.We will not use Javascript.Javascript is required for IE 7, IE 8 and the notorious IE 6. The best solution for implementing corners using CSS and Javascript without using images is Nifty corners cube. There are detailed information how to achieve this in the link I provided. This solution is tested in earlier vesrions of IE (IE 6,IE 7,IE 8) and Opera,Firefox,Safari. In order to be absolutely clear this is not (and could not be) a detailed tutorial on HTML 5. There are other great resources for that.Navigate to the excellent interactive tutorials of W3School.Another excellent resource is HTML 5 Doctor.Two very nice sites that show you what features and specifications are implemented by various browsers and their versions are http://caniuse.com/ and http://html5test.com/. At this times Chrome seems to support most of HTML 5 specifications.Another excellent way to find out if the browser supports HTML 5 and CSS 3 features is to use the Javascript lightweight library Modernizr.In this hands-on example I will be using Expression Web 4.0.This application is not a free application. You can use any HTML editor you like.You can use Visual Studio 2012 Express edition. You can download it here.Before I go on with the actual demo I will use the (http://www.caniuse.com) to see the support for web fonts from the latest versions of modern browsers.Please have a look at the picture below. We see that all the latest versions of modern browsers support this feature.We can see that even IE 9 supports this feature.  Let's move on with the actual demo. This is going to be a rather simple demo.I create a simple HTML 5 page. The markup follows and it is very easy to use and understand <!DOCTYPE html><html lang="en">  <head>    <title>HTML 5, CSS3 and JQuery</title>    <meta http-equiv="Content-Type" content="text/html;charset=utf-8" >    <link rel="stylesheet" type="text/css" href="style.css">       </head>  <body>      <div id="header">      <h1>Learn cutting edge technologies</h1>    </div>        <div id="main">          <h2>HTML 5</h2>                        <p id="panel1">            HTML5 is the latest version of HTML and XHTML. The HTML standard defines a single language that can be written in HTML and XML. It attempts to solve issues found in previous iterations of HTML and addresses the needs of Web Applications, an area previously not adequately covered by HTML.          </p>      </div>             </body>  </html>Then I need to write the various CSS rules that style this markup. I will name it style.css   body{        line-height: 38px;        width: 1024px;        background-color:#eee;        text-align:center;      }#panel1 { margin:auto; text-align:left; background-color:#77cdef;width:400px; height:250px; padding:15px;font-size:16px;font-family:tahoma;color:#fff;border-radius: 20px;}Have a look below to see what my page looks like in IE 10. This is possible through the border-radious property. The colored panel has all four corners rounded with the same radius.We can add a border to the rounded corner panel by adding this property declaration in the #panel1,  border:4px #000 solid;We can have even better visual effects if we specify a radius for each corner.This is the updated version of the style.css. body{        line-height: 38px;        width: 1024px;        background-color:#eee;        text-align:center;      }#panel1 { margin:auto; text-align:left; background-color:#77cdef;border:4px #000 solid;width:400px; height:250px; padding:15px;font-size:16px;font-family:tahoma;color:#fff;border-top-left-radius: 20px;border-top-right-radius: 70px;border-bottom-right-radius: 20px;border-bottom-left-radius: 70px;} This is how my page looks in Firefox 15.0.1  In this final example I will show you how to style with CSS 3 (rounded corners) a horizontal navigation menu. This is the new version of the HTML markup<!DOCTYPE html><html lang="en">  <head>    <title>HTML 5, CSS3 and JQuery</title>    <meta http-equiv="Content-Type" content="text/html;charset=utf-8" >    <link rel="stylesheet" type="text/css" href="style.css">       </head>  <body>      <div id="header">      <h1>Learn cutting edge technologies</h1>    </div>        <div id="nav"><ul><li><a class="mymenu" id="activelink" href="http://weblogs.asp.net/controlpanel/blogs/posteditor.aspx?SelectedNavItem=Posts§ionid=1153&postid=8934038#">Main</a></li><li><a class="mymenu" href="http://weblogs.asp.net/controlpanel/blogs/posteditor.aspx?SelectedNavItem=Posts§ionid=1153&postid=8934038#">HTML 5</a></li><li><a class="mymenu" href="http://weblogs.asp.net/controlpanel/blogs/posteditor.aspx?SelectedNavItem=Posts§ionid=1153&postid=8934038#">CSS 3</a></li><li><a class="mymenu" href="http://weblogs.asp.net/controlpanel/blogs/posteditor.aspx?SelectedNavItem=Posts§ionid=1153&postid=8934038#">JQuery</a></li></ul></div>        <div id="main">          <h2>HTML 5</h2>                        <p id="panel1">            HTML5 is the latest version of HTML and XHTML. The HTML standard defines a single language that can be written in HTML and XML. It attempts to solve issues found in previous iterations of HTML and addresses the needs of Web Applications, an area previously not adequately covered by HTML.          </p>      </div>             </body>  </html> This is the updated version of style.css body{        line-height: 38px;        width: 1024px;        background-color:#eee;        text-align:center;      }#panel1 { margin:auto; text-align:left; background-color:#77cdef;border:4px #000 solid;width:400px; height:250px; padding:15px;font-size:16px;font-family:tahoma;color:#fff;border-top-left-radius: 20px;border-top-right-radius: 70px;border-bottom-right-radius: 20px;border-bottom-left-radius: 70px;}#nav ul {width:900px; position:relative;top:24px;}ul li { text-decoration:none; display:inline;}ul li a.mymenu { font-family:Tahoma; color:black; font-size:14px;font-weight:bold;background-color:#77cdef; color:#fff;border-top-left-radius:18px; border-top-right-radius:18px; border:1px solid black; padding:15px; padding-bottom:10px;margin :2px; text-decoration:none; border-bottom:none;}.mymenu:hover { background-color:#e3781a; color:black;} The CSS rules are the classic rules that are extensively used for styling menus.The border-radius property is still responsible for the rounded corners in the menu.This is how my page looks in Chrome version 21.  Hope it helps!!!

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  • Why do my LWJGL fonts have dots and lines around them?

    - by Jordan
    When we render fonts there are weird dots and lines around the text. I have no idea why this would happen. Here is an image of what it looks like: Our font class looks like this: package me.NJ.ComputerTycoon.Font; import me.NJ.ComputerTycoon.BaseObjects.UDim2; import org.lwjgl.opengl.Display; import org.newdawn.slick.Color; import org.newdawn.slick.TrueTypeFont; public class Font { public TrueTypeFont font; private int fontSize = 18; private String fontName = "Calibri"; private int fontStyle = java.awt.Font.BOLD; public Font(String fontName, int fontStyle, int fontSize) { font = new TrueTypeFont(new java.awt.Font(fontName, fontStyle, fontSize), true); //font. } public Font(int fontStyle, int fontSize) { font = new TrueTypeFont(new java.awt.Font(fontName, fontStyle, fontSize), true); } public Font(int fontSize) { font = new TrueTypeFont(new java.awt.Font(fontName, fontStyle, fontSize), true); } public Font() { font = new TrueTypeFont(new java.awt.Font(fontName, fontStyle, fontSize), true); } public void drawString(int x, int y, String s, Color color){ this.font.drawString(x, y, s, color); } public void drawString(int x, int y, String s){ this.font.drawString(x, y, s); } public void drawString(float x, float y, String s, Color color){ this.font.drawString(x, y, s, color); } public void drawString(float x, float y, String s){ this.font.drawString(x, y, s); } public void drawString(UDim2 udim, String s){ this.font.drawString((Display.getWidth() * udim.getX().getScale()) + udim.getX().getOffset(), (Display.getHeight() * udim.getY().getScale()) + udim.getY().getOffset(), s); } public String getFontName(){ return this.fontName; } public int getFontSize(){ return this.fontSize; } public TrueTypeFont getFont(){ return this.font; } } What could be causing this?

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  • Create a Texture2D from larger image

    - by Dialock
    I am having trouble with the basic logic of this solution: Xna: Splitting one large texture into an array of smaller textures in respect to my specific problem (specifically, I'm looking at the second answer.) How can I use my source rectangle that I already use for drawing to create a new Texture2D? spriteBatch.Draw(CurrentMap.CollisionSet, currentMap.CellScreenRectangle(x, y), CurrentMap.TileSourceRectangle(currentMap.MapCells[x, y].TileDepths[4]), Color.FromNonPremultiplied(0,0,0, 45), 0.0f, Vector2.Zero, SpriteEffects.None, 0.91f); I know I want a method that I started so: //In Update Method of say the player's character. Texture2D CollisionTexture = ExtractTexture(MapManager.CurrentMap.CollisionSet, MapManager.TileWidth, MapManager.TileHeight); // In MapManager Class who knows everything about tiles that make up a level. public Texture2D ExtractTexture(Texture2D original, int partWidth, int partheight, MapTile mapCell) { var dataPerPart = partWidth * partheight; Color[] originalPixelData = new Color[original.Width * original.Height]; original.GetData<Color>(originalPixelData); Color[] newTextureData = new Color[dataPerPart]; original.GetData<Color>(0, CurrentMap.TileSourceRectangle(mapCell.TileDepths[4]), originalPixelData, 0, originalPixelData.Count()); Texture2D outTexture = new Texture2D(original.GraphicsDevice, partWidth, partheight); } I think the problem is I'm just not understanding the overload of Texture2D.GetData< Part of my concern is creating an array of the whole texture in the first place. Can I target the original texture and create an array of colors for copying based on what I already get from the method TileSourceRecatangle(int)?

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  • Can not print after upgrading from 12.x to 14.04

    - by user318889
    After upgrading from V12.04 to V14.04 I am not able to print. I am using an HP LaserJet 400 M451dn. The printer troubleshooter told me that there is no solution to the problem. This is the output of the advanced diagnositc output. (Due to limited space I cut the output!) Can anybody tell me what is going wrong. I am using the printer via USB ? Page 1 (Scheduler not running?): {'cups_connection_failure': False} Page 2 (Is local server publishing?): {'local_server_exporting_printers': False} Page 3 (Choose printer): {'cups_dest': , 'cups_instance': None, 'cups_queue': u'HP-LaserJet-400-color-M451dn', 'cups_queue_listed': True} Page 4 (Check printer sanity): {'cups_device_uri_scheme': u'hp', 'cups_printer_dict': {'device-uri': u'hp:/usb/HP_LaserJet_400_color_M451dn?serial=CNFF308670', 'printer-info': u'Hewlett-Packard HP LaserJet 400 color M451dn', 'printer-is-shared': True, 'printer-location': u'Pinatubo', 'printer-make-and-model': u'HP LJ 300-400 color M351-M451 Postscript (recommended)', 'printer-state': 4, 'printer-state-message': u'', 'printer-state-reasons': [u'none'], 'printer-type': 8556636, 'printer-uri-supported': u'ipp://localhost:631/printers/HP-LaserJet-400-color-M451dn'}, 'cups_printer_remote': False, 'hplip_output': (['', '\x1b[01mHP Linux Imaging and Printing System (ver. 3.14.6)\x1b[0m', '\x1b[01mDevice Information Utility ver. 5.2\x1b[0m', '', 'Copyright (c) 2001-13 Hewlett-Packard Development Company, LP', 'This software comes with ABSOLUTELY NO WARRANTY.', 'This is free software, and you are welcome to distribute it', 'under certain conditions. See COPYING file for more details.', '', '', '\x1b[01mhp:/usb/HP_LaserJet_400_color_M451dn?serial=CNFF308670\x1b[0m', '', '\x1b[01mDevice Parameters (dynamic data):\x1b[0m', '\x1b[01m Parameter Value(s) \x1b[0m', ' ---------------------------- ----------------------------------------------------------', ' back-end hp ', " cups-printers ['HP-LaserJet-400-color-M451dn'] ", ' cups-uri hp:/usb/HP_LaserJet_400_color_M451dn?serial=CNFF308670 ', ' dev-file ', ' device-state -1 ', ' device-uri hp:/usb/HP_LaserJet_400_color_M451dn?serial=CNFF308670 ', ' deviceid ', ' error-state 101 ', ' host ', ' is-hp True ', ' panel 0 ', ' panel-line1 ', ' panel-line2 ', ' port 1 ', ' serial CNFF308670 ', ' status-code 5002 ', ' status-desc ', '\x1b[01m', 'Model Parameters (static data):\x1b[0m', '\x1b[01m Parameter Value(s) \x1b[0m', ' ---------------------------- ----------------------------------------------------------', ' align-type 0 ', ' clean-type 0 ', ' color-cal-type 0 ', ' copy-type 0 ', ' embedded-server-type 0 ', ' fax-type 0 ', ' fw-download False ', ' icon hp_color_laserjet_cp2025.png ', ' io-mfp-mode 1 ', ' io-mode 1 ', ' io-support 6 ', ' job-storage 0 ', ' linefeed-cal-type 0 ', ' model HP_LaserJet_400_color_M451dn ', ' model-ui HP LaserJet 400 Color m451dn ', ' model1 HP LaserJet 400 Color M451dn ', ' monitor-type 0 ', ' panel-check-type 0 ', ' pcard-type 0 ', ' plugin 0 ', ' plugin-reason 0 ', ' power-settings 0 ', ' ppd-name lj_300_400_color_m351_m451 ', ' pq-diag-type 0 ', ' r-type 0 ', ' r0-agent1-kind 4 ', ' r0-agent1-sku CE410A/CE410X ', ' r0-agent1-type 1 ', ' r0-agent2-kind 4 ', ' r0-agent2-sku CE411A ', ' r0-agent2-type 4 ', ' r0-agent3-kind 4 ', ' r0-agent3-sku CE413A ', ' r0-agent3-type 5 ', ' r0-agent4-kind 4 ', ' r0-agent4-sku CE412A ', ' r0-agent4-type 6 ', ' scan-src 0 ', ' scan-type 0 ', ' status-battery-check 0 ', ' status-dynamic-counters 0 ', ' status-type 3 ', ' support-released True ', ' support-subtype 2202411 ', ' support-type 2 ', ' support-ver 3.12.2 ', " tech-class ['Postscript'] ", " tech-subclass ['Normal'] ", ' tech-type 4 ', ' usb-pid 3882 ', ' usb-vid 1008 ', ' wifi-config 0 ', '\x1b[01m', 'Status History (most recent first):\x1b[0m', '\x1b[01m Date/Time Code Status Description User Job ID \x1b[0m', ' -------------------- ----- ---------------------------------------- -------- --------', ' 08/21/14 00:07:25 5012 Device communication error richard 0 ', ' 08/20/14 13:42:44 500 Started a print job richard 4214 ', '', '', 'Done.', ''], ['\x1b[35;01mwarning: No display found.\x1b[0m', '\x1b[31;01merror: hp-info -u/--gui requires Qt4 GUI support. Entering interactive mode.\x1b[0m', '\x1b[31;01merror: Unable to communicate with device (code=12): hp:/usb/HP_LaserJet_400_color_M451dn?serial=CNFF308670\x1b[0m', '\x1b[31;01merror: Error opening device (Device not found).\x1b[0m', ''], 0), 'is_cups_class': False, 'local_cups_queue_attributes': {'charset-configured': u'utf-8', 'charset-supported': [u'us-ascii', u'utf-8'], 'color-supported': True, 'compression-supported': [u'none', u'gzip'], 'copies-default': 1, 'copies-supported': (1, 9999), 'cups-version': u'1.7.2', 'device-uri': u'hp:/usb/HP_LaserJet_400_color_M451dn?serial=CNFF308670', 'document-format-default': u'application/octet-stream', 'document-format-supported': [u'application/octet-stream', u'application/pdf', u'application/postscript', u'application/vnd.adobe-reader-postscript', u'application/vnd.cups-command', u'application/vnd.cups-pdf', u'application/vnd.cups-pdf-banner', u'application/vnd.cups-postscript', u'application/vnd.cups-raw', u'application/vnd.samsung-ps', u'application/x-cshell', u'application/x-csource', u'application/x-perl', u'application/x-shell', u'image/gif', u'image/jpeg', u'image/png', u'image/tiff', u'image/urf', u'image/x-bitmap', u'image/x-photocd', u'image/x-portable-anymap', u'image/x-portable-bitmap', u'image/x-portable-graymap', u'image/x-portable-pixmap', u'image/x-sgi-rgb', u'image/x-sun-raster', u'image/x-xbitmap', u'image/x-xpixmap', u'image/x-xwindowdump', u'text/css', u'text/html', u'text/plain'], 'finishings-default': 3, 'finishings-supported': [3], 'generated-natural-language-supported': [u'en-us'], 'ipp-versions-supported': [u'1.0', u'1.1', u'2.0', u'2.1'], 'ippget-event-life': 15, 'job-creation-attributes-supported': [u'copies', u'finishings', u'ipp-attribute-fidelity', u'job-hold-until', u'job-name', u'job-priority', u'job-sheets', u'media', u'media-col', u'multiple-document-handling', u'number-up', u'output-bin', u'orientation-requested', u'page-ranges', u'print-color-mode', u'print-quality', u'printer-resolution', u'sides'], 'job-hold-until-default': u'no-hold', 'job-hold-until-supported': [u'no-hold', u'indefinite', u'day-time', u'evening', u'night', u'second-shift', u'third-shift', u'weekend'], 'job-ids-supported': True, 'job-k-limit': 0, 'job-k-octets-supported': (0, 470914416), 'job-page-limit': 0, 'job-priority-default': 50, 'job-priority-supported': [100], 'job-quota-period': 0, 'job-settable-attributes-supported': [u'copies', u'finishings', u'job-hold-until', u'job-name', u'job-priority', u'media', u'media-col', u'multiple-document-handling', u'number-up', u'output-bin', u'orientation-requested', u'page-ranges', u'print-color-mode', u'print-quality', u'printer-resolution', u'sides'], 'job-sheets-default': (u'none', u'none'), 'job-sheets-supported': [u'none', u'classified', u'confidential', u'form', u'secret', u'standard', u'topsecret', u'unclassified'], 'jpeg-k-octets-supported': (0, 470914416), 'jpeg-x-dimension-supported': (0, 65535), 'jpeg-y-dimension-supported': (1, 65535), 'marker-change-time': 0, 'media-bottom-margin-supported': [423], 'media-col-default': u'(unknown IPP value tag 0x34)', 'media-col-supported': [u'media-bottom-margin', u'media-left-margin', u'media-right-margin', u'media-size', u'media-source', u'media-top-margin', u'media-type'], 'media-default': u'iso_a4_210x297mm', 'media-left-margin-supported': [423], 'media-right-margin-supported': [423],

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  • How does Windows 7 taskbar "color hot-tracking" feature calculate the colour to use?

    - by theyetiman
    This has intrigued me for quite some time. Does anyone know the algorithm Windows 7 Aero uses to determine the colour to use as the hot-tracking hover highlight on taskbar buttons for currently-running apps? It is definitely based on the icon of the app, but I can't see a specific pattern of where it's getting the colour value from. It doesn't seem to be any of the following: An average colour value from the entire icon, otherwise you would get brown all the time with multi-coloured icons like Chrome. The colour used the most in the image, otherwise you'd get yellow for the SQL Server Management Studio icon (6th from left). Also, the Chrome icon used red, green and yellow in equal measure. A colour located at certain pixel coordinates within the icon, because Chrome is red -indicating the top of the icon - and Notepad++ (2nd from right) is green - indicating the bottom of the icon. I asked this question on ux.stackoverflow.com and it got closed as off-topic, but someone answered with the following: As described by Raymond Chen in this MSDN blog article: Some people ask how it's done. It's really nothing special. The code just looks for the predominant color in the icon. (And, since visual designers are sticklers for this sort of thing, black, white, and shades of gray are not considered "colors" for the purpose of this calculation.) However I wasn't really satisfied with that answer because it doesn't explain how the "predominant" colour is calculated. Surely on the SQL Management Studio icon, the predominant colour, to my eyes at least, is yellow. Yet the highlight is green. I want to know, specifically, what the algorithm is.

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  • Parallelism in .NET – Part 14, The Different Forms of Task

    - by Reed
    Before discussing Task creation and actual usage in concurrent environments, I will briefly expand upon my introduction of the Task class and provide a short explanation of the distinct forms of Task.  The Task Parallel Library includes four distinct, though related, variations on the Task class. In my introduction to the Task class, I focused on the most basic version of Task.  This version of Task, the standard Task class, is most often used with an Action delegate.  This allows you to implement for each task within the task decomposition as a single delegate. Typically, when using the new threading constructs in .NET 4 and the Task Parallel Library, we use lambda expressions to define anonymous methods.  The advantage of using a lambda expression is that it allows the Action delegate to directly use variables in the calling scope.  This eliminates the need to make separate Task classes for Action<T>, Action<T1,T2>, and all of the other Action<…> delegate types.  As an example, suppose we wanted to make a Task to handle the ”Show Splash” task from our earlier decomposition.  Even if this task required parameters, such as a message to display, we could still use an Action delegate specified via a lambda: // Store this as a local variable string messageForSplashScreen = GetSplashScreenMessage(); // Create our task Task showSplashTask = new Task( () => { // We can use variables in our outer scope, // as well as methods scoped to our class! this.DisplaySplashScreen(messageForSplashScreen); }); .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } This provides a huge amount of flexibility.  We can use this single form of task for any task which performs an operation, provided the only information we need to track is whether the task has completed successfully or not.  This leads to my first observation: Use a Task with a System.Action delegate for any task for which no result is generated. This observation leads to an obvious corollary: we also need a way to define a task which generates a result.  The Task Parallel Library provides this via the Task<TResult> class. Task<TResult> subclasses the standard Task class, providing one additional feature – the ability to return a value back to the user of the task.  This is done by switching from providing an Action delegate to providing a Func<TResult> delegate.  If we decompose our problem, and we realize we have one task where its result is required by a future operation, this can be handled via Task<TResult>.  For example, suppose we want to make a task for our “Check for Update” task, we could do: Task<bool> checkForUpdateTask = new Task<bool>( () => { return this.CheckWebsiteForUpdate(); }); Later, we would start this task, and perform some other work.  At any point in the future, we could get the value from the Task<TResult>.Result property, which will cause our thread to block until the task has finished processing: // This uses Task<bool> checkForUpdateTask generated above... // Start the task, typically on a background thread checkForUpdateTask.Start(); // Do some other work on our current thread this.DoSomeWork(); // Discover, from our background task, whether an update is available // This will block until our task completes bool updateAvailable = checkForUpdateTask.Result; This leads me to my second observation: Use a Task<TResult> with a System.Func<TResult> delegate for any task which generates a result. Task and Task<TResult> provide a much cleaner alternative to the previous Asynchronous Programming design patterns in the .NET framework.  Instead of trying to implement IAsyncResult, and providing BeginXXX() and EndXXX() methods, implementing an asynchronous programming API can be as simple as creating a method that returns a Task or Task<TResult>.  The client side of the pattern also is dramatically simplified – the client can call a method, then either choose to call task.Wait() or use task.Result when it needs to wait for the operation’s completion. While this provides a much cleaner model for future APIs, there is quite a bit of infrastructure built around the current Asynchronous Programming design patterns.  In order to provide a model to work with existing APIs, two other forms of Task exist.  There is a constructor for Task which takes an Action<Object> and a state parameter.  In addition, there is a constructor for creating a Task<TResult> which takes a Func<Object, TResult> as well as a state parameter.  When using these constructors, the state parameter is stored in the Task.AsyncState property. While these two overloads exist, and are usable directly, I strongly recommend avoiding this for new development.  The two forms of Task which take an object state parameter exist primarily for interoperability with traditional .NET Asynchronous Programming methodologies.  Using lambda expressions to capture variables from the scope of the creator is a much cleaner approach than using the untyped state parameters, since lambda expressions provide full type safety without introducing new variables.

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  • Parallelism in .NET – Part 15, Making Tasks Run: The TaskScheduler

    - by Reed
    In my introduction to the Task class, I specifically made mention that the Task class does not directly provide it’s own execution.  In addition, I made a strong point that the Task class itself is not directly related to threads or multithreading.  Rather, the Task class is used to implement our decomposition of tasks.  Once we’ve implemented our tasks, we need to execute them.  In the Task Parallel Library, the execution of Tasks is handled via an instance of the TaskScheduler class. The TaskScheduler class is an abstract class which provides a single function: it schedules the tasks and executes them within an appropriate context.  This class is the class which actually runs individual Task instances.  The .NET Framework provides two (internal) implementations of the TaskScheduler class. Since a Task, based on our decomposition, should be a self-contained piece of code, parallel execution makes sense when executing tasks.  The default implementation of the TaskScheduler class, and the one most often used, is based on the ThreadPool.  This can be retrieved via the TaskScheduler.Default property, and is, by default, what is used when we just start a Task instance with Task.Start(). Normally, when a Task is started by the default TaskScheduler, the task will be treated as a single work item, and run on a ThreadPool thread.  This pools tasks, and provides Task instances all of the advantages of the ThreadPool, including thread pooling for reduced resource usage, and an upper cap on the number of work items.  In addition, .NET 4 brings us a much improved thread pool, providing work stealing and reduced locking within the thread pool queues.  By using the default TaskScheduler, our Tasks are run asynchronously on the ThreadPool. There is one notable exception to my above statements when using the default TaskScheduler.  If a Task is created with the TaskCreationOptions set to TaskCreationOptions.LongRunning, the default TaskScheduler will generate a new thread for that Task, at least in the current implementation.  This is useful for Tasks which will persist for most of the lifetime of your application, since it prevents your Task from starving the ThreadPool of one of it’s work threads. The Task Parallel Library provides one other implementation of the TaskScheduler class.  In addition to providing a way to schedule tasks on the ThreadPool, the framework allows you to create a TaskScheduler which works within a specified SynchronizationContext.  This scheduler can be retrieved within a thread that provides a valid SynchronizationContext by calling the TaskScheduler.FromCurrentSynchronizationContext() method. This implementation of TaskScheduler is intended for use with user interface development.  Windows Forms and Windows Presentation Foundation both require any access to user interface controls to occur on the same thread that created the control.  For example, if you want to set the text within a Windows Forms TextBox, and you’re working on a background thread, that UI call must be marshaled back onto the UI thread.  The most common way this is handled depends on the framework being used.  In Windows Forms, Control.Invoke or Control.BeginInvoke is most often used.  In WPF, the equivelent calls are Dispatcher.Invoke or Dispatcher.BeginInvoke. As an example, say we’re working on a background thread, and we want to update a TextBlock in our user interface with a status label.  The code would typically look something like: // Within background thread work... string status = GetUpdatedStatus(); Dispatcher.BeginInvoke(DispatcherPriority.Normal, new Action( () => { statusLabel.Text = status; })); // Continue on in background method .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } This works fine, but forces your method to take a dependency on WPF or Windows Forms.  There is an alternative option, however.  Both Windows Forms and WPF, when initialized, setup a SynchronizationContext in their thread, which is available on the UI thread via the SynchronizationContext.Current property.  This context is used by classes such as BackgroundWorker to marshal calls back onto the UI thread in a framework-agnostic manner. The Task Parallel Library provides the same functionality via the TaskScheduler.FromCurrentSynchronizationContext() method.  When setting up our Tasks, as long as we’re working on the UI thread, we can construct a TaskScheduler via: TaskScheduler uiScheduler = TaskScheduler.FromCurrentSynchronizationContext(); We then can use this scheduler on any thread to marshal data back onto the UI thread.  For example, our code above can then be rewritten as: string status = GetUpdatedStatus(); (new Task(() => { statusLabel.Text = status; })) .Start(uiScheduler); // Continue on in background method This is nice since it allows us to write code that isn’t tied to Windows Forms or WPF, but is still fully functional with those technologies.  I’ll discuss even more uses for the SynchronizationContext based TaskScheduler when I demonstrate task continuations, but even without continuations, this is a very useful construct. In addition to the two implementations provided by the Task Parallel Library, it is possible to implement your own TaskScheduler.  The ParallelExtensionsExtras project within the Samples for Parallel Programming provides nine sample TaskScheduler implementations.  These include schedulers which restrict the maximum number of concurrent tasks, run tasks on a single threaded apartment thread, use a new thread per task, and more.

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  • Parallelism in .NET – Part 6, Declarative Data Parallelism

    - by Reed
    When working with a problem that can be decomposed by data, we have a collection, and some operation being performed upon the collection.  I’ve demonstrated how this can be parallelized using the Task Parallel Library and imperative programming using imperative data parallelism via the Parallel class.  While this provides a huge step forward in terms of power and capabilities, in many cases, special care must still be given for relative common scenarios. C# 3.0 and Visual Basic 9.0 introduced a new, declarative programming model to .NET via the LINQ Project.  When working with collections, we can now write software that describes what we want to occur without having to explicitly state how the program should accomplish the task.  By taking advantage of LINQ, many operations become much shorter, more elegant, and easier to understand and maintain.  Version 4.0 of the .NET framework extends this concept into the parallel computation space by introducing Parallel LINQ. Before we delve into PLINQ, let’s begin with a short discussion of LINQ.  LINQ, the extensions to the .NET Framework which implement language integrated query, set, and transform operations, is implemented in many flavors.  For our purposes, we are interested in LINQ to Objects.  When dealing with parallelizing a routine, we typically are dealing with in-memory data storage.  More data-access oriented LINQ variants, such as LINQ to SQL and LINQ to Entities in the Entity Framework fall outside of our concern, since the parallelism there is the concern of the data base engine processing the query itself. LINQ (LINQ to Objects in particular) works by implementing a series of extension methods, most of which work on IEnumerable<T>.  The language enhancements use these extension methods to create a very concise, readable alternative to using traditional foreach statement.  For example, let’s revisit our minimum aggregation routine we wrote in Part 4: double min = double.MaxValue; foreach(var item in collection) { double value = item.PerformComputation(); min = System.Math.Min(min, value); } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } Here, we’re doing a very simple computation, but writing this in an imperative style.  This can be loosely translated to English as: Create a very large number, and save it in min Loop through each item in the collection. For every item: Perform some computation, and save the result If the computation is less than min, set min to the computation Although this is fairly easy to follow, it’s quite a few lines of code, and it requires us to read through the code, step by step, line by line, in order to understand the intention of the developer. We can rework this same statement, using LINQ: double min = collection.Min(item => item.PerformComputation()); Here, we’re after the same information.  However, this is written using a declarative programming style.  When we see this code, we’d naturally translate this to English as: Save the Min value of collection, determined via calling item.PerformComputation() That’s it – instead of multiple logical steps, we have one single, declarative request.  This makes the developer’s intentions very clear, and very easy to follow.  The system is free to implement this using whatever method required. Parallel LINQ (PLINQ) extends LINQ to Objects to support parallel operations.  This is a perfect fit in many cases when you have a problem that can be decomposed by data.  To show this, let’s again refer to our minimum aggregation routine from Part 4, but this time, let’s review our final, parallelized version: // Safe, and fast! double min = double.MaxValue; // Make a "lock" object object syncObject = new object(); Parallel.ForEach( collection, // First, we provide a local state initialization delegate. () => double.MaxValue, // Next, we supply the body, which takes the original item, loop state, // and local state, and returns a new local state (item, loopState, localState) => { double value = item.PerformComputation(); return System.Math.Min(localState, value); }, // Finally, we provide an Action<TLocal>, to "merge" results together localState => { // This requires locking, but it's only once per used thread lock(syncObj) min = System.Math.Min(min, localState); } ); Here, we’re doing the same computation as above, but fully parallelized.  Describing this in English becomes quite a feat: Create a very large number, and save it in min Create a temporary object we can use for locking Call Parallel.ForEach, specifying three delegates For the first delegate: Initialize a local variable to hold the local state to a very large number For the second delegate: For each item in the collection, perform some computation, save the result If the result is less than our local state, save the result in local state For the final delegate: Take a lock on our temporary object to protect our min variable Save the min of our min and local state variables Although this solves our problem, and does it in a very efficient way, we’ve created a set of code that is quite a bit more difficult to understand and maintain. PLINQ provides us with a very nice alternative.  In order to use PLINQ, we need to learn one new extension method that works on IEnumerable<T> – ParallelEnumerable.AsParallel(). That’s all we need to learn in order to use PLINQ: one single method.  We can write our minimum aggregation in PLINQ very simply: double min = collection.AsParallel().Min(item => item.PerformComputation()); By simply adding “.AsParallel()” to our LINQ to Objects query, we converted this to using PLINQ and running this computation in parallel!  This can be loosely translated into English easily, as well: Process the collection in parallel Get the Minimum value, determined by calling PerformComputation on each item Here, our intention is very clear and easy to understand.  We just want to perform the same operation we did in serial, but run it “as parallel”.  PLINQ completely extends LINQ to Objects: the entire functionality of LINQ to Objects is available.  By simply adding a call to AsParallel(), we can specify that a collection should be processed in parallel.  This is simple, safe, and incredibly useful.

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  • More CPU cores may not always lead to better performance – MAXDOP and query memory distribution in spotlight

    - by sqlworkshops
    More hardware normally delivers better performance, but there are exceptions where it can hinder performance. Understanding these exceptions and working around it is a major part of SQL Server performance tuning.   When a memory allocating query executes in parallel, SQL Server distributes memory to each task that is executing part of the query in parallel. In our example the sort operator that executes in parallel divides the memory across all tasks assuming even distribution of rows. Common memory allocating queries are that perform Sort and do Hash Match operations like Hash Join or Hash Aggregation or Hash Union.   In reality, how often are column values evenly distributed, think about an example; are employees working for your company distributed evenly across all the Zip codes or mainly concentrated in the headquarters? What happens when you sort result set based on Zip codes? Do all products in the catalog sell equally or are few products hot selling items?   One of my customers tested the below example on a 24 core server with various MAXDOP settings and here are the results:MAXDOP 1: CPU time = 1185 ms, elapsed time = 1188 msMAXDOP 4: CPU time = 1981 ms, elapsed time = 1568 msMAXDOP 8: CPU time = 1918 ms, elapsed time = 1619 msMAXDOP 12: CPU time = 2367 ms, elapsed time = 2258 msMAXDOP 16: CPU time = 2540 ms, elapsed time = 2579 msMAXDOP 20: CPU time = 2470 ms, elapsed time = 2534 msMAXDOP 0: CPU time = 2809 ms, elapsed time = 2721 ms - all 24 cores.In the above test, when the data was evenly distributed, the elapsed time of parallel query was always lower than serial query.   Why does the query get slower and slower with more CPU cores / higher MAXDOP? Maybe you can answer this question after reading the article; let me know: [email protected].   Well you get the point, let’s see an example.   The best way to learn is to practice. To create the below tables and reproduce the behavior, join the mailing list by using this link: www.sqlworkshops.com/ml and I will send you the table creation script.   Let’s update the Employees table with 49 out of 50 employees located in Zip code 2001. update Employees set Zip = EmployeeID / 400 + 1 where EmployeeID % 50 = 1 update Employees set Zip = 2001 where EmployeeID % 50 != 1 go update statistics Employees with fullscan go   Let’s create the temporary table #FireDrill with all possible Zip codes. drop table #FireDrill go create table #FireDrill (Zip int primary key) insert into #FireDrill select distinct Zip from Employees update statistics #FireDrill with fullscan go  Let’s execute the query serially with MAXDOP 1. --Example provided by www.sqlworkshops.com --Execute query with uneven Zip code distribution --First serially with MAXDOP 1 set statistics time on go declare @EmployeeID int, @EmployeeName varchar(48),@zip int select @EmployeeName = e.EmployeeName, @zip = e.Zip from Employees e       inner join #FireDrill fd on (e.Zip = fd.Zip)       order by e.Zip option (maxdop 1) goThe query took 1011 ms to complete.   The execution plan shows the 77816 KB of memory was granted while the estimated rows were 799624.  No Sort Warnings in SQL Server Profiler.  Now let’s execute the query in parallel with MAXDOP 0. --Example provided by www.sqlworkshops.com --Execute query with uneven Zip code distribution --In parallel with MAXDOP 0 set statistics time on go declare @EmployeeID int, @EmployeeName varchar(48),@zip int select @EmployeeName = e.EmployeeName, @zip = e.Zip from Employees e       inner join #FireDrill fd on (e.Zip = fd.Zip)       order by e.Zip option (maxdop 0) go The query took 1912 ms to complete.  The execution plan shows the 79360 KB of memory was granted while the estimated rows were 799624.  The estimated number of rows between serial and parallel plan are the same. The parallel plan has slightly more memory granted due to additional overhead. Sort properties shows the rows are unevenly distributed over the 4 threads.   Sort Warnings in SQL Server Profiler.   Intermediate Summary: The reason for the higher duration with parallel plan was sort spill. This is due to uneven distribution of employees over Zip codes, especially concentration of 49 out of 50 employees in Zip code 2001. Now let’s update the Employees table and distribute employees evenly across all Zip codes.   update Employees set Zip = EmployeeID / 400 + 1 go update statistics Employees with fullscan go  Let’s execute the query serially with MAXDOP 1. --Example provided by www.sqlworkshops.com --Execute query with uneven Zip code distribution --Serially with MAXDOP 1 set statistics time on go declare @EmployeeID int, @EmployeeName varchar(48),@zip int select @EmployeeName = e.EmployeeName, @zip = e.Zip from Employees e       inner join #FireDrill fd on (e.Zip = fd.Zip)       order by e.Zip option (maxdop 1) go   The query took 751 ms to complete.  The execution plan shows the 77816 KB of memory was granted while the estimated rows were 784707.  No Sort Warnings in SQL Server Profiler.   Now let’s execute the query in parallel with MAXDOP 0. --Example provided by www.sqlworkshops.com --Execute query with uneven Zip code distribution --In parallel with MAXDOP 0 set statistics time on go declare @EmployeeID int, @EmployeeName varchar(48),@zip int select @EmployeeName = e.EmployeeName, @zip = e.Zip from Employees e       inner join #FireDrill fd on (e.Zip = fd.Zip)       order by e.Zip option (maxdop 0) go The query took 661 ms to complete.  The execution plan shows the 79360 KB of memory was granted while the estimated rows were 784707.  Sort properties shows the rows are evenly distributed over the 4 threads. No Sort Warnings in SQL Server Profiler.    Intermediate Summary: When employees were distributed unevenly, concentrated on 1 Zip code, parallel sort spilled while serial sort performed well without spilling to tempdb. When the employees were distributed evenly across all Zip codes, parallel sort and serial sort did not spill to tempdb. This shows uneven data distribution may affect the performance of some parallel queries negatively. For detailed discussion of memory allocation, refer to webcasts available at www.sqlworkshops.com/webcasts.     Some of you might conclude from the above execution times that parallel query is not faster even when there is no spill. Below you can see when we are joining limited amount of Zip codes, parallel query will be fasted since it can use Bitmap Filtering.   Let’s update the Employees table with 49 out of 50 employees located in Zip code 2001. update Employees set Zip = EmployeeID / 400 + 1 where EmployeeID % 50 = 1 update Employees set Zip = 2001 where EmployeeID % 50 != 1 go update statistics Employees with fullscan go  Let’s create the temporary table #FireDrill with limited Zip codes. drop table #FireDrill go create table #FireDrill (Zip int primary key) insert into #FireDrill select distinct Zip       from Employees where Zip between 1800 and 2001 update statistics #FireDrill with fullscan go  Let’s execute the query serially with MAXDOP 1. --Example provided by www.sqlworkshops.com --Execute query with uneven Zip code distribution --Serially with MAXDOP 1 set statistics time on go declare @EmployeeID int, @EmployeeName varchar(48),@zip int select @EmployeeName = e.EmployeeName, @zip = e.Zip from Employees e       inner join #FireDrill fd on (e.Zip = fd.Zip)       order by e.Zip option (maxdop 1) go The query took 989 ms to complete.  The execution plan shows the 77816 KB of memory was granted while the estimated rows were 785594. No Sort Warnings in SQL Server Profiler.  Now let’s execute the query in parallel with MAXDOP 0. --Example provided by www.sqlworkshops.com --Execute query with uneven Zip code distribution --In parallel with MAXDOP 0 set statistics time on go declare @EmployeeID int, @EmployeeName varchar(48),@zip int select @EmployeeName = e.EmployeeName, @zip = e.Zip from Employees e       inner join #FireDrill fd on (e.Zip = fd.Zip)       order by e.Zip option (maxdop 0) go The query took 1799 ms to complete.  The execution plan shows the 79360 KB of memory was granted while the estimated rows were 785594.  Sort Warnings in SQL Server Profiler.    The estimated number of rows between serial and parallel plan are the same. The parallel plan has slightly more memory granted due to additional overhead.  Intermediate Summary: The reason for the higher duration with parallel plan even with limited amount of Zip codes was sort spill. This is due to uneven distribution of employees over Zip codes, especially concentration of 49 out of 50 employees in Zip code 2001.   Now let’s update the Employees table and distribute employees evenly across all Zip codes. update Employees set Zip = EmployeeID / 400 + 1 go update statistics Employees with fullscan go Let’s execute the query serially with MAXDOP 1. --Example provided by www.sqlworkshops.com --Execute query with uneven Zip code distribution --Serially with MAXDOP 1 set statistics time on go declare @EmployeeID int, @EmployeeName varchar(48),@zip int select @EmployeeName = e.EmployeeName, @zip = e.Zip from Employees e       inner join #FireDrill fd on (e.Zip = fd.Zip)       order by e.Zip option (maxdop 1) go The query took 250  ms to complete.  The execution plan shows the 9016 KB of memory was granted while the estimated rows were 79973.8.  No Sort Warnings in SQL Server Profiler.  Now let’s execute the query in parallel with MAXDOP 0.  --Example provided by www.sqlworkshops.com --Execute query with uneven Zip code distribution --In parallel with MAXDOP 0 set statistics time on go declare @EmployeeID int, @EmployeeName varchar(48),@zip int select @EmployeeName = e.EmployeeName, @zip = e.Zip from Employees e       inner join #FireDrill fd on (e.Zip = fd.Zip)       order by e.Zip option (maxdop 0) go The query took 85 ms to complete.  The execution plan shows the 13152 KB of memory was granted while the estimated rows were 784707.  No Sort Warnings in SQL Server Profiler.    Here you see, parallel query is much faster than serial query since SQL Server is using Bitmap Filtering to eliminate rows before the hash join.   Parallel queries are very good for performance, but in some cases it can hinder performance. If one identifies the reason for these hindrances, then it is possible to get the best out of parallelism. I covered many aspects of monitoring and tuning parallel queries in webcasts (www.sqlworkshops.com/webcasts) and articles (www.sqlworkshops.com/articles). I suggest you to watch the webcasts and read the articles to better understand how to identify and tune parallel query performance issues.   Summary: One has to avoid sort spill over tempdb and the chances of spills are higher when a query executes in parallel with uneven data distribution. Parallel query brings its own advantage, reduced elapsed time and reduced work with Bitmap Filtering. So it is important to understand how to avoid spills over tempdb and when to execute a query in parallel.   I explain these concepts with detailed examples in my webcasts (www.sqlworkshops.com/webcasts), I recommend you to watch them. The best way to learn is to practice. To create the above tables and reproduce the behavior, join the mailing list at www.sqlworkshops.com/ml and I will send you the relevant SQL Scripts.   Register for the upcoming 3 Day Level 400 Microsoft SQL Server 2008 and SQL Server 2005 Performance Monitoring & Tuning Hands-on Workshop in London, United Kingdom during March 15-17, 2011, click here to register / Microsoft UK TechNet.These are hands-on workshops with a maximum of 12 participants and not lectures. For consulting engagements click here.   Disclaimer and copyright information:This article refers to organizations and products that may be the trademarks or registered trademarks of their various owners. Copyright of this article belongs to R Meyyappan / www.sqlworkshops.com. You may freely use the ideas and concepts discussed in this article with acknowledgement (www.sqlworkshops.com), but you may not claim any of it as your own work. This article is for informational purposes only; you use any of the suggestions given here entirely at your own risk.   Register for the upcoming 3 Day Level 400 Microsoft SQL Server 2008 and SQL Server 2005 Performance Monitoring & Tuning Hands-on Workshop in London, United Kingdom during March 15-17, 2011, click here to register / Microsoft UK TechNet.These are hands-on workshops with a maximum of 12 participants and not lectures. For consulting engagements click here.   R Meyyappan [email protected] LinkedIn: http://at.linkedin.com/in/rmeyyappan  

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  • Launching a WPF Window in a Separate Thread, Part 1

    - by Reed
    Typically, I strongly recommend keeping the user interface within an application’s main thread, and using multiple threads to move the actual “work” into background threads.  However, there are rare times when creating a separate, dedicated thread for a Window can be beneficial.  This is even acknowledged in the MSDN samples, such as the Multiple Windows, Multiple Threads sample.  However, doing this correctly is difficult.  Even the referenced MSDN sample has major flaws, and will fail horribly in certain scenarios.  To ease this, I wrote a small class that alleviates some of the difficulties involved. The MSDN Multiple Windows, Multiple Threads Sample shows how to launch a new thread with a WPF Window, and will work in most cases.  The sample code (commented and slightly modified) works out to the following: // Create a thread Thread newWindowThread = new Thread(new ThreadStart( () => { // Create and show the Window Window1 tempWindow = new Window1(); tempWindow.Show(); // Start the Dispatcher Processing System.Windows.Threading.Dispatcher.Run(); })); // Set the apartment state newWindowThread.SetApartmentState(ApartmentState.STA); // Make the thread a background thread newWindowThread.IsBackground = true; // Start the thread newWindowThread.Start(); .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } This sample creates a thread, marks it as single threaded apartment state, and starts the Dispatcher on that thread. That is the minimum requirements to get a Window displaying and handling messages correctly, but, unfortunately, has some serious flaws. The first issue – the created thread will run continuously until the application shuts down, given the code in the sample.  The problem is that the ThreadStart delegate used ends with running the Dispatcher.  However, nothing ever stops the Dispatcher processing.  The thread was created as a Background thread, which prevents it from keeping the application alive, but the Dispatcher will continue to pump dispatcher frames until the application shuts down. In order to fix this, we need to call Dispatcher.InvokeShutdown after the Window is closed.  This would require modifying the above sample to subscribe to the Window’s Closed event, and, at that point, shutdown the Dispatcher: // Create a thread Thread newWindowThread = new Thread(new ThreadStart( () => { Window1 tempWindow = new Window1(); // When the window closes, shut down the dispatcher tempWindow.Closed += (s,e) => Dispatcher.CurrentDispatcher.BeginInvokeShutdown(DispatcherPriority.Background); tempWindow.Show(); // Start the Dispatcher Processing System.Windows.Threading.Dispatcher.Run(); })); // Setup and start thread as before This eliminates the first issue.  Now, when the Window is closed, the new thread’s Dispatcher will shut itself down, which in turn will cause the thread to complete. The above code will work correctly for most situations.  However, there is still a potential problem which could arise depending on the content of the Window1 class.  This is particularly nasty, as the code could easily work for most windows, but fail on others. The problem is, at the point where the Window is constructed, there is no active SynchronizationContext.  This is unlikely to be a problem in most cases, but is an absolute requirement if there is code within the constructor of Window1 which relies on a context being in place. While this sounds like an edge case, it’s fairly common.  For example, if a BackgroundWorker is started within the constructor, or a TaskScheduler is built using TaskScheduler.FromCurrentSynchronizationContext() with the expectation of synchronizing work to the UI thread, an exception will be raised at some point.  Both of these classes rely on the existence of a proper context being installed to SynchronizationContext.Current, which happens automatically, but not until Dispatcher.Run is called.  In the above case, SynchronizationContext.Current will return null during the Window’s construction, which can cause exceptions to occur or unexpected behavior. Luckily, this is fairly easy to correct.  We need to do three things, in order, prior to creating our Window: Create and initialize the Dispatcher for the new thread manually Create a synchronization context for the thread which uses the Dispatcher Install the synchronization context Creating the Dispatcher is quite simple – The Dispatcher.CurrentDispatcher property gets the current thread’s Dispatcher and “creates a new Dispatcher if one is not already associated with the thread.”  Once we have the correct Dispatcher, we can create a SynchronizationContext which uses the dispatcher by creating a DispatcherSynchronizationContext.  Finally, this synchronization context can be installed as the current thread’s context via SynchronizationContext.SetSynchronizationContext.  These three steps can easily be added to the above via a single line of code: // Create a thread Thread newWindowThread = new Thread(new ThreadStart( () => { // Create our context, and install it: SynchronizationContext.SetSynchronizationContext( new DispatcherSynchronizationContext( Dispatcher.CurrentDispatcher)); Window1 tempWindow = new Window1(); // When the window closes, shut down the dispatcher tempWindow.Closed += (s,e) => Dispatcher.CurrentDispatcher.BeginInvokeShutdown(DispatcherPriority.Background); tempWindow.Show(); // Start the Dispatcher Processing System.Windows.Threading.Dispatcher.Run(); })); // Setup and start thread as before This now forces the synchronization context to be in place before the Window is created and correctly shuts down the Dispatcher when the window closes. However, there are quite a few steps.  In my next post, I’ll show how to make this operation more reusable by creating a class with a far simpler API…

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  • Creating and maintaining Orchard translations

    - by Bertrand Le Roy
    Many volunteers have already stepped up to provide translations for Orchard. There are many challenges to overcome with translating such a project. Orchard is a very modular CMS, so the translation mechanism needs to account for the core as well as first and third party modules and themes. Another issue is that every new version of Orchard or of a module changes some localizable strings and adds new ones as others enter obsolescence. In order to address those problems, I've built a small Orchard module that automates some of the most complex tasks that maintaining a translation implies. In this post, I'll walk you through the operations I had to do to update the French translation for Orchard 1.0. In order to make sure you translate all the first party modules, I would recommend that you start from a full source code enlistment. The reason is that I'll show how you can extract the default en-US translation from any source code enlistment. That enables you to create a translation that is even more up-to-date than what is currently on the site. Alternatively, you could start by downloading the current en-US translation. If you decide to do so, just skip the relevant paragraphs. First, let's install the Orchard Translation Manager. I'm starting from a vanilla clone of the latest in the code repository. After you've setup the site, go into the dashboard and click on Gallery. Locate the Orchard Translation Manager in the list of modules and click "Install". Once the module is installed, you need to enable its one feature by going into Configuration/Features and clicking "Enable" next to Vandelay.TranslationManager. We're done with the setup that we need in order to start our translation work. We'll now switch to the command-line and to our favorite text editor. Open a command-line on the Orchard web site folder. I found the easiest way to do this is to do a SHIFT+right-click on the Orchard.Web folder in Windows Explorer and to click "Open command window here". Type bin\orchard to enter the Orchard command-line environment. If you do a "help commands" you should see four commands in the list that came from the module we just installed: extract default translation, install translation, package translation and sync translation. First, we're going to generate the default translation. Note that it is possible to generate that default translation for a specific list of modules and themes by using the /Extensions: switch, which should facilitate the translation of third party extensions, but in this tutorial we're going to generate it for the whole of the Orchard source code. extract default translation /Output:\temp .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } This should have created an Orchard.en-us.po.zip file in the temp directory. Extract that archive into an orchard.po folder under \temp. The next step depends on whether you have an existing translation that you want to update or not. If you do have an existing translation, just extract it into the same \temp\orchard.po directory. That should result in a file structure where you have the default en-US translation alongside your own. If you don't have an existing translation, just continue, the commands will be the same. We are now going to synchronize those translations (or generate the stub for a new one if you didn't start from an existing translation). sync translation /Input:\temp\orchard.po /Culture:fr-FR After this command (where you should of course substitute fr-FR with the culture you're working on), we now have updated files that contain a few useful flags. Open each of the .po files under the culture you are working on (there should be around 36) with your favorite text editor. For all the strings that are still valid in the latest version, nothing changes and you don't need to do anything. For all the strings that disappeared from the default culture, the old translation will still be there but they will be prefixed with the following comment: # Obsolete translation Conveniently, all the obsolete strings will be grouped at the end of the file. You can select all those and delete them. For all the new strings, you will see the following comment: # Untranslated string This is where the hard work begins. You'll need to translate each of those new strings by entering the translation between the quotes in: msgstr "" Don't introduce hard carriage returns in the strings, just stay on one line (your text editor should do some reasonable wrapping so this shouldn't be a big deal). Once you're done with a file, save it. Make sure, and this is very important, that your text editor is saving using the UTF-8 encoding. In Notepad, that setting can be found in the file saving dialog by doing a "Save As" rather than a plain "Save": When all the po files have been edited, you are ready to package the translation for submission (a.k.a. sending e-mail to the localization mailing list). package translation /Culture:fr-FR /Input:\temp\orchard.po /Output:\temp You should now see a Orchard.fr-FR.po.zip file in temp that is ready to be submitted. That is, once you've tested it, which can be done by deploying it into the site: install translation \temp\orchard.fr-fr.po.zip Once this is done you can go into the dashboard under Configuration/Settings and click on "Add or remove supported cultures for the site". Choose your culture and click "Add". You can go back to settings and set the default culture. Save. You may now take a tour of the application and verify that everything works as expected: And that's it really. Creating a translation for Orchard is a matter of a few hours. If you don't see a translation for your culture, please consider creating it.

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  • New Features in ASP.NET Web API 2 - Part I

    - by dwahlin
    I’m a big fan of ASP.NET Web API. It provides a quick yet powerful way to build RESTful HTTP services that can easily be consumed by a variety of clients. While it’s simple to get started using, it has a wealth of features such as filters, formatters, and message handlers that can be used to extend it when needed. In this post I’m going to provide a quick walk-through of some of the key new features in version 2. I’ll focus on some two of my favorite features that are related to routing and HTTP responses and cover additional features in a future post.   Attribute Routing Routing has been a core feature of Web API since it’s initial release and something that’s built into new Web API projects out-of-the-box. However, there are a few scenarios where defining routes can be challenging such as nested routes (more on that in a moment) and any situation where a lot of custom routes have to be defined. For this example, let’s assume that you’d like to define the following nested route:   /customers/1/orders   This type of route would select a customer with an Id of 1 and then return all of their orders. Defining this type of route in the standard WebApiConfig class is certainly possible, but it isn’t the easiest thing to do for people who don’t understand routing well. Here’s an example of how the route shown above could be defined:   public static class WebApiConfig { public static void Register(HttpConfiguration config) { config.Routes.MapHttpRoute( name: "CustomerOrdersApiGet", routeTemplate: "api/customers/{custID}/orders", defaults: new { custID = 0, controller = "Customers", action = "Orders" } ); config.Routes.MapHttpRoute( name: "DefaultApi", routeTemplate: "api/{controller}/{id}", defaults: new { id = RouteParameter.Optional } ); GlobalConfiguration.Configuration.Formatters.Insert(0, new JsonpFormatter()); } } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; }   With attribute based routing, defining these types of nested routes is greatly simplified. To get started you first need to make a call to the new MapHttpAttributeRoutes() method in the standard WebApiConfig class (or a custom class that you may have created that defines your routes) as shown next:   public static class WebApiConfig { public static void Register(HttpConfiguration config) { // Allow for attribute based routes config.MapHttpAttributeRoutes(); config.Routes.MapHttpRoute( name: "DefaultApi", routeTemplate: "api/{controller}/{id}", defaults: new { id = RouteParameter.Optional } ); } } Once attribute based routes are configured, you can apply the Route attribute to one or more controller actions. Here’s an example:   [HttpGet] [Route("customers/{custId:int}/orders")] public List<Order> Orders(int custId) { var orders = _Repository.GetOrders(custId); if (orders == null) { throw new HttpResponseException(new HttpResponseMessage(HttpStatusCode.NotFound)); } return orders; }   This example maps the custId route parameter to the custId parameter in the Orders() method and also ensures that the route parameter is typed as an integer. The Orders() method can be called using the following route: /customers/2/orders   While this is extremely easy to use and gets the job done, it doesn’t include the default “api” string on the front of the route that you might be used to seeing. You could add “api” in front of the route and make it “api/customers/{custId:int}/orders” but then you’d have to repeat that across other attribute-based routes as well. To simply this type of task you can add the RoutePrefix attribute above the controller class as shown next so that “api” (or whatever the custom starting point of your route is) is applied to all attribute routes: [RoutePrefix("api")] public class CustomersController : ApiController { [HttpGet] [Route("customers/{custId:int}/orders")] public List<Order> Orders(int custId) { var orders = _Repository.GetOrders(custId); if (orders == null) { throw new HttpResponseException(new HttpResponseMessage(HttpStatusCode.NotFound)); } return orders; } }   There’s much more that you can do with attribute-based routing in ASP.NET. Check out the following post by Mike Wasson for more details.   Returning Responses with IHttpActionResult The first version of Web API provided a way to return custom HttpResponseMessage objects which were pretty easy to use overall. However, Web API 2 now wraps some of the functionality available in version 1 to simplify the process even more. A new interface named IHttpActionResult (similar to ActionResult in ASP.NET MVC) has been introduced which can be used as the return type for Web API controller actions. To return a custom response you can use new helper methods exposed through ApiController such as: Ok NotFound Exception Unauthorized BadRequest Conflict Redirect InvalidModelState Here’s an example of how IHttpActionResult and the helper methods can be used to cleanup code. This is the typical way to return a custom HTTP response in version 1:   public HttpResponseMessage Delete(int id) { var status = _Repository.DeleteCustomer(id); if (status) { return new HttpResponseMessage(HttpStatusCode.OK); } else { throw new HttpResponseException(HttpStatusCode.NotFound); } } With version 2 we can replace HttpResponseMessage with IHttpActionResult and simplify the code quite a bit:   public IHttpActionResult Delete(int id) { var status = _Repository.DeleteCustomer(id); if (status) { //return new HttpResponseMessage(HttpStatusCode.OK); return Ok(); } else { //throw new HttpResponseException(HttpStatusCode.NotFound); return NotFound(); } } You can also cleanup post (insert) operations as well using the helper methods. Here’s a version 1 post action:   public HttpResponseMessage Post([FromBody]Customer cust) { var newCust = _Repository.InsertCustomer(cust); if (newCust != null) { var msg = new HttpResponseMessage(HttpStatusCode.Created); msg.Headers.Location = new Uri(Request.RequestUri + newCust.ID.ToString()); return msg; } else { throw new HttpResponseException(HttpStatusCode.Conflict); } } This is what the code looks like in version 2:   public IHttpActionResult Post([FromBody]Customer cust) { var newCust = _Repository.InsertCustomer(cust); if (newCust != null) { return Created<Customer>(Request.RequestUri + newCust.ID.ToString(), newCust); } else { return Conflict(); } } More details on IHttpActionResult and the different helper methods provided by the ApiController base class can be found here. Conclusion Although there are several additional features available in Web API 2 that I could cover (CORS support for example), this post focused on two of my favorites features. If you have .NET 4.5.1 available then I definitely recommend checking the new features out. Additional articles that cover features in ASP.NET Web API 2 can be found here.

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  • Adding RSS to tags in Orchard

    - by Bertrand Le Roy
    A year ago, I wrote a scary post about RSS in Orchard. RSS was one of the first features we implemented in our CMS, and it has stood the test of time rather well, but the post was explaining things at a level that was probably too abstract whereas my readers were expecting something a little more practical. Well, this post is going to correct this by showing how I built a module that adds RSS feeds for each tag on the site. Hopefully it will show that it's not very complicated in practice, and also that the infrastructure is pretty well thought out. In order to provide RSS, we need to do two things: generate the XML for the feed, and inject the address of that feed into the existing tag listing page, in order to make the feed discoverable. Let's start with the discoverability part. One might be tempted to replace the controller or the view that are responsible for the listing of the items under a tag. Fortunately, there is no need to do any of that, and we can be a lot less obtrusive. Instead, we can implement a filter: public class TagRssFilter : FilterProvider, IResultFilter .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } On this filter, we can implement the OnResultExecuting method and simply check whether the current request is targeting the list of items under a tag. If that is the case, we can just register our new feed: public void OnResultExecuting(ResultExecutingContext filterContext) { var routeValues = filterContext.RouteData.Values; if (routeValues["area"] as string == "Orchard.Tags" && routeValues["controller"] as string == "Home" && routeValues["action"] as string == "Search") { var tag = routeValues["tagName"] as string; if (! string.IsNullOrWhiteSpace(tag)) { var workContext = _wca.GetContext(); _feedManager.Register( workContext.CurrentSite + " – " + tag, "rss", new RouteValueDictionary { { "tag", tag } } ); } } } The registration of the new feed is just specifying the title of the feed, its format (RSS) and the parameters that it will need (the tag). _wca and _feedManager are just instances of IWorkContextAccessor and IFeedManager that Orchard injected for us. That is all that's needed to get the following tag to be added to the head of our page, without touching an existing controller or view: <link rel="alternate" type="application/rss+xml" title="VuLu - Science" href="/rss?tag=Science"/> Nifty. Of course, if we navigate to the URL of that feed, we'll get a 404. This is because no implementation of IFeedQueryProvider knows about the tag parameter yet. Let's build one that does: public class TagFeedQuery : IFeedQueryProvider, IFeedQuery IFeedQueryProvider has one method, Match, that we can implement to take over any feed request that has a tag parameter: public FeedQueryMatch Match(FeedContext context) { var tagName = context.ValueProvider.GetValue("tag"); if (tagName == null) return null; return new FeedQueryMatch { FeedQuery = this, Priority = -5 }; } This is just saying that if there is a tag parameter, we will handle it. All that remains to be done is the actual building of the feed now that we have accepted to handle it. This is done by implementing the Execute method of the IFeedQuery interface: public void Execute(FeedContext context) { var tagValue = context.ValueProvider.GetValue("tag"); if (tagValue == null) return; var tagName = (string)tagValue.ConvertTo(typeof (string)); var tag = _tagService.GetTagByName(tagName); if (tag == null) return; var site = _services.WorkContext.CurrentSite; var link = new XElement("link"); context.Response.Element.SetElementValue("title", site.SiteName + " - " + tagName); context.Response.Element.Add(link); context.Response.Element.SetElementValue("description", site.SiteName + " - " + tagName); context.Response.Contextualize(requestContext => link.Add(GetTagUrl(tagName, requestContext))); var items = _tagService.GetTaggedContentItems(tag.Id, 0, 20); foreach (var item in items) { context.Builder.AddItem(context, item.ContentItem); } } This code is resolving the tag content item from its name and then gets content items tagged with it, using the tag services provided by the Orchard.Tags module. Then we add those items to the feed. And that is it. To summarize, we handled the request unobtrusively in order to inject the feed's link, then handled requests for feeds with a tag parameter and generated the list of items for that tag. It remains fairly simple and still it is able to handle arbitrary content types. That makes me quite happy about our little piece of over-engineered code from last year. The full code for this can be found in the Vandelay.TagCloud module: http://orchardproject.net/gallery/List/Modules/ Orchard.Module.Vandelay.TagCloud/1.2

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  • Creating a podcast feed for iTunes & BlackBerry users using WCF Syndication

    - by brian_ritchie
     In my previous post, I showed how to create a RSS feed using WCF Syndication.  Next, I'll show how to add the additional tags needed to turn a RSS feed into an iTunes podcast.   A podcast is merely a RSS feed with some special characteristics: iTunes RSS tags.  These are additional tags beyond the standard RSS spec.  Apple has a good page on the requirements. Audio file enclosure.  This is a link to the audio file (such as mp3) hosted by your site.  Apple doesn't host the audio, they just read the meta-data from the RSS feed into their system. The SyndicationFeed class supports both AttributeExtensions & ElementExtensions to add custom tags to the RSS feeds. A couple of points of interest in the code below: The imageUrl below provides the album cover for iTunes (170px × 170px) Each SyndicationItem corresponds to an audio episode in your podcast So, here's the code: .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: Consolas, "Courier New", Courier, Monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } 1: XNamespace itunesNS = "http://www.itunes.com/dtds/podcast-1.0.dtd"; 2: string prefix = "itunes"; 3:   4: var feed = new SyndicationFeed(title, description, new Uri(link)); 5: feed.Categories.Add(new SyndicationCategory(category)); 6: feed.AttributeExtensions.Add(new XmlQualifiedName(prefix, 7: "http://www.w3.org/2000/xmlns/"), itunesNS.NamespaceName); 8: feed.Copyright = new TextSyndicationContent(copyright); 9: feed.Language = "en-us"; 10: feed.Copyright = new TextSyndicationContent(DateTime.Now.Year + " " + ownerName); 11: feed.ImageUrl = new Uri(imageUrl); 12: feed.LastUpdatedTime = DateTime.Now; 13: feed.Authors.Add(new SyndicationPerson() {Name=ownerName, Email=ownerEmail }); 14: var extensions = feed.ElementExtensions; 15: extensions.Add(new XElement(itunesNS + "subtitle", subTitle).CreateReader()); 16: extensions.Add(new XElement(itunesNS + "image", 17: new XAttribute("href", imageUrl)).CreateReader()); 18: extensions.Add(new XElement(itunesNS + "author", ownerName).CreateReader()); 19: extensions.Add(new XElement(itunesNS + "summary", description).CreateReader()); 20: extensions.Add(new XElement(itunesNS + "category", 21: new XAttribute("text", category), 22: new XElement(itunesNS + "category", 23: new XAttribute("text", subCategory))).CreateReader()); 24: extensions.Add(new XElement(itunesNS + "explicit", "no").CreateReader()); 25: extensions.Add(new XDocument( 26: new XElement(itunesNS + "owner", 27: new XElement(itunesNS + "name", ownerName), 28: new XElement(itunesNS + "email", ownerEmail))).CreateReader()); 29:   30: var feedItems = new List<SyndicationItem>(); 31: foreach (var i in Items) 32: { 33: var item = new SyndicationItem(i.title, null, new Uri(link)); 34: item.Summary = new TextSyndicationContent(i.summary); 35: item.Id = i.id; 36: if (i.publishedDate != null) 37: item.PublishDate = (DateTimeOffset)i.publishedDate; 38: item.Links.Add(new SyndicationLink() { 39: Title = i.title, Uri = new Uri(link), 40: Length = i.size, MediaType = i.mediaType }); 41: var itemExt = item.ElementExtensions; 42: itemExt.Add(new XElement(itunesNS + "subtitle", i.subTitle).CreateReader()); 43: itemExt.Add(new XElement(itunesNS + "summary", i.summary).CreateReader()); 44: itemExt.Add(new XElement(itunesNS + "duration", 45: string.Format("{0}:{1:00}:{2:00}", 46: i.duration.Hours, i.duration.Minutes, i.duration.Seconds) 47: ).CreateReader()); 48: itemExt.Add(new XElement(itunesNS + "keywords", i.keywords).CreateReader()); 49: itemExt.Add(new XElement(itunesNS + "explicit", "no").CreateReader()); 50: itemExt.Add(new XElement("enclosure", new XAttribute("url", i.url), 51: new XAttribute("length", i.size), new XAttribute("type", i.mediaType))); 52: feedItems.Add(item); 53: } 54:   55: feed.Items = feedItems; If you're hosting your podcast feed within a MVC project, you can use the code from my previous post to stream it. Once you have created your feed, you can use the Feed Validator tool to make sure it is up to spec.  Or you can use iTunes: Launch iTunes. In the Advanced menu, select Subscribe to Podcast. Enter your feed URL in the text box and click OK. After you've verified your feed is solid & good to go, you can submit it to iTunes.  Launch iTunes. In the left navigation column, click on iTunes Store to open the store. Once the store loads, click on Podcasts along the top navigation bar to go to the Podcasts page. In the right column of the Podcasts page, click on the Submit a Podcast link. Follow the instructions on the Submit a Podcast page. Here are the full instructions.  Once they have approved your podcast, it will be available within iTunes. RIM has also gotten into the podcasting business...which is great for BlackBerry users.  They accept the same enhanced-RSS feed that iTunes uses, so just create an account with them & submit the feed's URL.  It goes through a similar approval process to iTunes.  BlackBerry users must be on BlackBerry 6 OS or download the Podcast App from App World. In my next post, I'll show how to build the podcast feed dynamically from the ID3 tags within the MP3 files.

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  • No Alias's when sudo'ing

    - by Danny Roberts
    I was playing around with aliases today and I noticed that aliases don't seem to be available whilst using sudo: danny@kaon:~$ alias alias egrep='egrep --color=auto' alias fgrep='fgrep --color=auto' alias grep='grep --color=auto' alias l='ls -CF' alias la='ls -A' alias ll='ls -alF' alias ls='ls --color=auto' danny@kaon:~$ ll -d / drwxr-xr-x 23 root root 4096 2011-01-06 20:29 // danny@kaon:~$ sudo -i root@kaon:~# ll -d / drwxr-xr-x 23 root root 4096 2011-01-06 20:29 // root@kaon:~# exit logout danny@kaon:~$ sudo ll -d / sudo: ll: command not found Is there any reason why you cannot use aliases whilst using sudo?

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  • Aliases not available when using sudo

    - by Danny Roberts
    I was playing around with aliases today and I noticed that aliases don't seem to be available whilst using sudo: danny@kaon:~$ alias alias egrep='egrep --color=auto' alias fgrep='fgrep --color=auto' alias grep='grep --color=auto' alias l='ls -CF' alias la='ls -A' alias ll='ls -alF' alias ls='ls --color=auto' danny@kaon:~$ ll -d / drwxr-xr-x 23 root root 4096 2011-01-06 20:29 // danny@kaon:~$ sudo -i root@kaon:~# ll -d / drwxr-xr-x 23 root root 4096 2011-01-06 20:29 // root@kaon:~# exit logout danny@kaon:~$ sudo ll -d / sudo: ll: command not found Is there any reason why you cannot use aliases whilst using sudo?

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  • A Quick HLSL Question (How to modify some HLSL code)

    - by electroflame
    Thanks for wanting to help! I'm trying to create a circular, repeating ring (that moves outward) on a texture. I've achieved this, to a degree, with the following code: float distance = length(inTex - in_ShipCenter); float time = in_Time; ///* Simple distance/time combination */ float2 colorIndex = float2(distance - time, .3); float4 shipColor = tex2D(BaseTexture, inTex); float4 ringColor = tex2D(ringTexture, colorIndex); float4 finalColor; finalColor.rgb = (shipColor.rgb) + (ringColor.rgb); finalColor.a = shipColor.a; // Use the base texture's alpha (transparency). return finalColor; This works, and works how I want it to. The ring moves outward from the center of the texture at a steady rate, and is constrained to the edges of the base texture (i.e. it won't continue past an edge). However, there are a few issues with it that I would like some help on, though. They are: By combining the color additively (when I set finalColor.rgb), it makes the resulting ring color much lighter than I want (which, is pretty much the definition of additive blending, but I don't really want additive blending in this case). I would really like to be able to pass in the color that I want the ring to be. Currently, I have to pass in a texture that contains the color of the ring, but I think that doing it that way is kind of wasteful and overly-cumbersome. I know that I'm probably being an idiot over this, so I greatly appreciate the help. Some other (possibly relevant) information: I'm using XNA. I'm applying this by providing it to a SpriteBatch (as an Effect). The SpriteBatch is using BlendState.NonPremultiplied. Thanks in advance! EDIT: Thanks for the answers thus far, as they've helped me get a better grasp of the color issue. However, I'm still unsure of how to pass a color in and not use a texture. i.e. Can I create a tex2D by using a float4 instead of a texture? Or can I make a texture from a float4 and pass the texture in to the tex2D? DOUBLE EDIT: Here's some example pictures: With the effect off: With the effect on: With the effect on, but with the color weighting set to full: As you can see, the color weighting makes the base texture completely black (The background is black, so it looks transparent). You can also see the red it's supposed to be, and then the white-ish it really is when blended additively.

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  • C# Performance Pitfall – Interop Scenarios Change the Rules

    - by Reed
    C# and .NET, overall, really do have fantastic performance in my opinion.  That being said, the performance characteristics dramatically differ from native programming, and take some relearning if you’re used to doing performance optimization in most other languages, especially C, C++, and similar.  However, there are times when revisiting tricks learned in native code play a critical role in performance optimization in C#. I recently ran across a nasty scenario that illustrated to me how dangerous following any fixed rules for optimization can be… The rules in C# when optimizing code are very different than C or C++.  Often, they’re exactly backwards.  For example, in C and C++, lifting a variable out of loops in order to avoid memory allocations often can have huge advantages.  If some function within a call graph is allocating memory dynamically, and that gets called in a loop, it can dramatically slow down a routine. This can be a tricky bottleneck to track down, even with a profiler.  Looking at the memory allocation graph is usually the key for spotting this routine, as it’s often “hidden” deep in call graph.  For example, while optimizing some of my scientific routines, I ran into a situation where I had a loop similar to: for (i=0; i<numberToProcess; ++i) { // Do some work ProcessElement(element[i]); } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } This loop was at a fairly high level in the call graph, and often could take many hours to complete, depending on the input data.  As such, any performance optimization we could achieve would be greatly appreciated by our users. After a fair bit of profiling, I noticed that a couple of function calls down the call graph (inside of ProcessElement), there was some code that effectively was doing: // Allocate some data required DataStructure* data = new DataStructure(num); // Call into a subroutine that passed around and manipulated this data highly CallSubroutine(data); // Read and use some values from here double values = data->Foo; // Cleanup delete data; // ... return bar; Normally, if “DataStructure” was a simple data type, I could just allocate it on the stack.  However, it’s constructor, internally, allocated it’s own memory using new, so this wouldn’t eliminate the problem.  In this case, however, I could change the call signatures to allow the pointer to the data structure to be passed into ProcessElement and through the call graph, allowing the inner routine to reuse the same “data” memory instead of allocating.  At the highest level, my code effectively changed to something like: DataStructure* data = new DataStructure(numberToProcess); for (i=0; i<numberToProcess; ++i) { // Do some work ProcessElement(element[i], data); } delete data; Granted, this dramatically reduced the maintainability of the code, so it wasn’t something I wanted to do unless there was a significant benefit.  In this case, after profiling the new version, I found that it increased the overall performance dramatically – my main test case went from 35 minutes runtime down to 21 minutes.  This was such a significant improvement, I felt it was worth the reduction in maintainability. In C and C++, it’s generally a good idea (for performance) to: Reduce the number of memory allocations as much as possible, Use fewer, larger memory allocations instead of many smaller ones, and Allocate as high up the call stack as possible, and reuse memory I’ve seen many people try to make similar optimizations in C# code.  For good or bad, this is typically not a good idea.  The garbage collector in .NET completely changes the rules here. In C#, reallocating memory in a loop is not always a bad idea.  In this scenario, for example, I may have been much better off leaving the original code alone.  The reason for this is the garbage collector.  The GC in .NET is incredibly effective, and leaving the allocation deep inside the call stack has some huge advantages.  First and foremost, it tends to make the code more maintainable – passing around object references tends to couple the methods together more than necessary, and overall increase the complexity of the code.  This is something that should be avoided unless there is a significant reason.  Second, (unlike C and C++) memory allocation of a single object in C# is normally cheap and fast.  Finally, and most critically, there is a large advantage to having short lived objects.  If you lift a variable out of the loop and reuse the memory, its much more likely that object will get promoted to Gen1 (or worse, Gen2).  This can cause expensive compaction operations to be required, and also lead to (at least temporary) memory fragmentation as well as more costly collections later. As such, I’ve found that it’s often (though not always) faster to leave memory allocations where you’d naturally place them – deep inside of the call graph, inside of the loops.  This causes the objects to stay very short lived, which in turn increases the efficiency of the garbage collector, and can dramatically improve the overall performance of the routine as a whole. In C#, I tend to: Keep variable declarations in the tightest scope possible Declare and allocate objects at usage While this tends to cause some of the same goals (reducing unnecessary allocations, etc), the goal here is a bit different – it’s about keeping the objects rooted for as little time as possible in order to (attempt) to keep them completely in Gen0, or worst case, Gen1.  It also has the huge advantage of keeping the code very maintainable – objects are used and “released” as soon as possible, which keeps the code very clean.  It does, however, often have the side effect of causing more allocations to occur, but keeping the objects rooted for a much shorter time. Now – nowhere here am I suggesting that these rules are hard, fast rules that are always true.  That being said, my time spent optimizing over the years encourages me to naturally write code that follows the above guidelines, then profile and adjust as necessary.  In my current project, however, I ran across one of those nasty little pitfalls that’s something to keep in mind – interop changes the rules. In this case, I was dealing with an API that, internally, used some COM objects.  In this case, these COM objects were leading to native allocations (most likely C++) occurring in a loop deep in my call graph.  Even though I was writing nice, clean managed code, the normal managed code rules for performance no longer apply.  After profiling to find the bottleneck in my code, I realized that my inner loop, a innocuous looking block of C# code, was effectively causing a set of native memory allocations in every iteration.  This required going back to a “native programming” mindset for optimization.  Lifting these variables and reusing them took a 1:10 routine down to 0:20 – again, a very worthwhile improvement. Overall, the lessons here are: Always profile if you suspect a performance problem – don’t assume any rule is correct, or any code is efficient just because it looks like it should be Remember to check memory allocations when profiling, not just CPU cycles Interop scenarios often cause managed code to act very differently than “normal” managed code. Native code can be hidden very cleverly inside of managed wrappers

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  • Why do some games randomly turn my screen a random solid color?

    - by Emlena.PhD
    When playing some games my computer will randomly have an error that I cannot fix without turning it off and back on again. The screen changes to one solid color, which varies (off the top of my head I can remember seeing solid green, magenta, etc..) and the sound blares a single tone. The sound sometimes briefly restores and I can still hear the game sounds and even hear and still be heard by people in my Mumble channel, but the screen doesn't right itself so I'm still blind. What's more is this happens in some games but not in others. While the game is actually running, not while I'm still in the menu. However, it does happen if I'm afk or idle but the game world is still rendering. Games where the error occurs: League of Legends World of Warcraft Trine The Sims 2 Dungeon Defenders Safe games: games where it has never occurred: Tribes: Ascend Star Wars: the Old Republic Battlefield 3 So relatively older games cause the problem while newer games do not? I cannot predict when it will happen, it just seems random. However, if it happens and I try playing the same game further after restart it does appear to occur more frequently after the first time. But if I switch to a safe game it doesn't continue happening. Both of my RAM sticks appear fine, flipped position or either one on their own and games still run, computer still boots. I would think over-heating, but then why not all games? ALso, sometimes it happens immediately after I start playing, within seconds of the 3D world booting up. I'm looking to upgrade very soon so I want to figure out what component or software is fubar and replace/repair it. Any suggestions or recommendations of tools would be helpful. Below is some system information. Dxdiag does not detect any problems. Operating System: Windows 7 Home Premium 64-bit (6.1, Build 7601) Service Pack 1 (7601.win7sp1_gdr.120305-1505) System Manufacturer: Gigabyte Technology Co., Ltd. System Model: EP45-UD3R BIOS: Award Modular BIOS v6.00PG Processor: Intel(R) Core(TM)2 Duo CPU E8500 @ 3.16GHz (2 CPUs), ~3.2GHz Memory: 4096MB RAM DirectX Version: DirectX 11 DxDiag Version: 6.01.7601.17514 64bit Unicode Graphics card name: NVIDIA GeForce GTX 285 Driver Version: 8.17.12.9610 (error has occurred w/several driver versions) Sound: I do not have a sound card, been using motherboard's built in sound)

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  • How can I remap control+e to escape+control+e in iTerm2?

    - by cwd
    I have set up a few custom keyboard shortcuts in iTerm2 to easily move the cursor around with the arrow keys, but now I'd like to remap control+e to be escape, control+e because bash 4.2 no longer auto-expands variables using the tab key. I know I've done the first part correctly in choosing the keyboard shortcut to remap, but I don't understand how to look up the correct escape sequence (or hex codes) to send in the bottom section: I reference they keyboard codes but that wasn't much help. How can I remap this, and how can I look up the codes in the future? (No luck with Google) Update @db - thanks. To save others trouble I also found a cool util Key Codes.app which can be used to find key codes:

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  • Should you apply a language filter to a randomly generated string?

    - by Tim
    A while back I created a licensing system for my companies new product, as well as all products after this one. As with a lot of licensing systems mine generates codes: 25 character product and registration codes, as well as 16 character module unlocking codes. My question is, since some parts of these generated codes are random should I apply a language filter to it to avoid any embarrassing language being given to the end users? I chose to as it was not difficult at all. But has anyone else ever came across something like this? Any viewpoints as to if it is worth the effort?

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