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  • ASP.NET 4 Unleashed in Bookstores!

    - by Stephen Walther
    I’m happy to announce that ASP.NET 4 Unleashed is now in bookstores! The book is over 1,800 pages and it is packed with code samples and tutorials on all the features of ASP.NET 4. Given the size of the book – did I mention that it is over 1,800 pages? -- I can safely say that it is the most comprehensive book on ASP.NET  This edition of the book has several new chapters written by Kevin Hoffman and Nate Dudek. Kevin and Nate did a fantastic job of covering the new features of ASP.NET 4 including: The new ASP.NET Chart Control The new ASP.NET QueryExtender Control The new ASP.NET routing framework jQuery You can buy the book from your local bookstore or buy the book from Amazon:

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  • ASP.NET in Moscow!

    - by Stephen Walther
    I’m traveling to Russia and speaking in Moscow next week at the DevConf. This will be the first time that I have visited Russia, and I know that there is a strong ASP.NET community in Russia, so I am very excited about the trip. I’m speaking at the DevConf (http://www.devconf.ru/). I don’t speak Russian, so the only words that I recognize off the home page of the conference website are ASP.NET and JavaScript (PHP, Perl, Python, and Ruby must be Russian words). I’m giving talks on both ASP.NET Web Forms and ASP.NET MVC: What’s New in ASP.NET 4 Web Forms Learn about the new features just released with ASP.NET 4 Web Forms and Visual Studio 2010 that enable you to be more productive and build better websites. Learn how to take control of your markup, client IDs, and view state. Learn how to take advantage of routing with Web Forms to make your websites more search engine friendly.   What’s New in ASP.NET MVC 2 Come learn about the new features being introduced with ASP.NET MVC 2. Templated helpers allow associating edit and display elements with data types automatically. Areas provide a means of dividing a large Web application into multiple projects. Data annotations allows attaching metadata attributes on a model to control validation. Client validation enables form field validation without the need to perform a roundtrip to the server. Learn how these new features enable you to be more productive when building ASP.NET MVC applications. Hope to see you at the conference next week!

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  • Microsoft, jQuery, and Templating

    - by Stephen Walther
    About two months ago, John Resig and I met at Café Algiers in Harvard square to discuss how Microsoft can contribute to the jQuery project. Today, Scott Guthrie announced in his second-day MIX keynote that Microsoft is throwing its weight behind jQuery and making it the primary way to develop client-side Ajax applications using Microsoft technologies. What does this announcement mean? It means that Microsoft is shifting its resources to invest in jQuery. Developers on the ASP.NET team are now working full-time to contribute features to the core jQuery library. Furthermore, we are working with other teams at Microsoft to ensure that our technologies work great with jQuery. We are contributing to the open-source jQuery project in the exact same way that any other company or individual from the community can contribute to jQuery. We are writing proposals, submitting the proposals to the jQuery forums, and revising the proposals in response to community feedback. The jQuery team can decide to reject or accept any feature that we propose. Any feature that Microsoft contributes to jQuery will be platform neutral. In other words, Microsoft contributions will benefit PHP and RAILS developers just as much as they benefit ASP.NET developers. Microsoft contributions to jQuery will improve the web for everyone. Contributing Support for Templates to jQuery Core Our first proposal concerns templating. We want to contribute support for templates to jQuery so that JavaScript developers can use jQuery to easily display a set of database records. You can read our templating proposal here: http://wiki.github.com/nje/jquery/jquery-templates-proposal You can download and play with our prototype for templating here: http://github.com/nje/jquery-tmpl The following code illustrates how you can use a template to display a set of products in a bulleted list: <script type="text/javascript"> jQuery(function(){ var products = [ { name: "Product 1", price: 12.99}, { name: "Product 2", price: 9.99}, { name: "Product 3", price: 35.59} ]; $("ul").append("#template", products); }); </script> <script id="template" type="text/html"> <li>{%= name %} - {%= price %}</li> </script> <ul></ul> The template is contained in a SCRIPT element that has a TYPE=”text/html” attribute. Browsers ignore the contents of a SCRIPT element when they don’t understand the content type. Notice that the placeholder {%=...%} is used within the template to indicate where the name and price of a product should appear. The delimiters {%=…%} are used for expressions and the delimiters {%...%} are used for code. Finally, the products are rendered using the template with the call to $(“ul”).append(“#template”, products). The standard jQuery DOM manipulation methods have been modified to support templates. When the page above is rendered, you get the bulleted list displayed in the following figure. Our goal is to keep our proposal for templates as simple as possible. After support for templating has been added to jQuery, plug-in authors can take advantage of templating when building complex data-driven plug-ins such as a DataGrid plug-in. The Ajax Control Toolkit Over 100,000 developers download the Ajax Control Toolkit every month. That’s a mind-boggling number of downloads. We realize that the Ajax Control Toolkit is extremely popular among ASP.NET Web Forms developers and we want to continue to invest in the Ajax Control Toolkit. If you are adding JavaScript interactivity to an ASP.NET Web Forms application, and you don’t want to write JavaScript, then we recommend that you use the server controls in the Ajax Control Toolkit. Using the Ajax Control Toolkit does not require knowledge of JavaScript and the toolkit enables you to build applications with the concepts familiar to ASP.NET Web Forms applications developers. If, however, you are interested in creating client-side interactivity without server controls then we recommend that you use jQuery. We plan to continue to release new versions of the Ajax Control Toolkit every few months. Our goal is to continue to improve the quality of the Ajax Control Toolkit and to make it easier for the community to contribute code, bug fixes, and documentation. The ASP.NET Ajax Library We are moving the ASP.NET Ajax Library into the Ajax Control Toolkit. If you currently use ASP.NET Ajax Library client templates, client data-binding, or the client script loader then you can continue to use these features by downloading the Ajax Control Toolkit. Be aware that our focus with the Ajax Control Toolkit is server-side Ajax.  For client-side Ajax, we are shifting our focus to jQuery. For example, if you have been using ASP.NET Ajax Library client templates then we recommend that you shift to using jQuery instead. Conclusion Our plan is to focus on jQuery as the primary technology for building client-side Ajax applications moving forward. We want to adapt Microsoft technologies to work great with jQuery and we want to contribute features to jQuery that will make the web better for everyone. We are very excited to be working with the jQuery core team.

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  • April 2013 Release of the Ajax Control Toolkit

    - by Stephen.Walther
    I’m excited to announce the April 2013 release of the Ajax Control Toolkit. For this release, we focused on improving two controls: the AjaxFileUpload and the MaskedEdit controls. You can download the latest release from CodePlex at http://AjaxControlToolkit.CodePlex.com or, better yet, you can execute the following NuGet command within Visual Studio 2010/2012: There are three builds of the Ajax Control Toolkit: .NET 3.5, .NET 4.0, and .NET 4.5. A Better AjaxFileUpload Control We completely rewrote the AjaxFileUpload control for this release. We had two primary goals. First, we wanted to support uploading really large files. In particular, we wanted to support uploading multi-gigabyte files such as video files or application files. Second, we wanted to support showing upload progress on as many browsers as possible. The previous version of the AjaxFileUpload could show upload progress when used with Google Chrome or Mozilla Firefox but not when used with Apple Safari or Microsoft Internet Explorer. The new version of the AjaxFileUpload control shows upload progress when used with any browser. Using the AjaxFileUpload Control Let me walk-through using the AjaxFileUpload in the most basic scenario. And then, in following sections, I can explain some of its more advanced features. Here’s how you can declare the AjaxFileUpload control in a page: <ajaxToolkit:ToolkitScriptManager runat="server" /> <ajaxToolkit:AjaxFileUpload ID="AjaxFileUpload1" AllowedFileTypes="mp4" OnUploadComplete="AjaxFileUpload1_UploadComplete" runat="server" /> The exact appearance of the AjaxFileUpload control depends on the features that a browser supports. In the case of Google Chrome, which supports drag-and-drop upload, here’s what the AjaxFileUpload looks like: Notice that the page above includes two Ajax Control Toolkit controls: the AjaxFileUpload and the ToolkitScriptManager control. You always need to include the ToolkitScriptManager with any page which uses Ajax Control Toolkit controls. The AjaxFileUpload control declared in the page above includes an event handler for its UploadComplete event. This event handler is declared in the code-behind page like this: protected void AjaxFileUpload1_UploadComplete(object sender, AjaxControlToolkit.AjaxFileUploadEventArgs e) { // Save uploaded file to App_Data folder AjaxFileUpload1.SaveAs(MapPath("~/App_Data/" + e.FileName)); } This method saves the uploaded file to your website’s App_Data folder. I’m assuming that you have an App_Data folder in your project – if you don’t have one then you need to create one or you will get an error. There is one more thing that you must do in order to get the AjaxFileUpload control to work. The AjaxFileUpload control relies on an HTTP Handler named AjaxFileUploadHandler.axd. You need to declare this handler in your application’s root web.config file like this: <configuration> <system.web> <compilation debug="true" targetFramework="4.5" /> <httpRuntime targetFramework="4.5" maxRequestLength="42949672" /> <httpHandlers> <add verb="*" path="AjaxFileUploadHandler.axd" type="AjaxControlToolkit.AjaxFileUploadHandler, AjaxControlToolkit"/> </httpHandlers> </system.web> <system.webServer> <validation validateIntegratedModeConfiguration="false"/> <handlers> <add name="AjaxFileUploadHandler" verb="*" path="AjaxFileUploadHandler.axd" type="AjaxControlToolkit.AjaxFileUploadHandler, AjaxControlToolkit"/> </handlers> <security> <requestFiltering> <requestLimits maxAllowedContentLength="4294967295"/> </requestFiltering> </security> </system.webServer> </configuration> Notice that the web.config file above also contains configuration settings for the maxRequestLength and maxAllowedContentLength. You need to assign large values to these configuration settings — as I did in the web.config file above — in order to accept large file uploads. Supporting Chunked File Uploads Because one of our primary goals with this release was support for large file uploads, we added support for client-side chunking. When you upload a file using a browser which fully supports the HTML5 File API — such as Google Chrome or Mozilla Firefox — then the file is uploaded in multiple chunks. You can see chunking in action by opening F12 Developer Tools in your browser and observing the Network tab: Notice that there is a crazy number of distinct post requests made (about 360 distinct requests for a 1 gigabyte file). Each post request looks like this: http://localhost:24338/AjaxFileUploadHandler.axd?contextKey={DA8BEDC8-B952-4d5d-8CC2-59FE922E2923}&fileId=B7CCE31C-6AB1-BB28-2940-49E0C9B81C64 &fileName=Sita_Sings_the_Blues_480p_2150kbps.mp4&chunked=true&firstChunk=false Each request posts another chunk of the file being uploaded. Notice that the request URL includes a chunked=true parameter which indicates that the browser is breaking the file being uploaded into multiple chunks. Showing Upload Progress on All Browsers The previous version of the AjaxFileUpload control could display upload progress only in the case of browsers which fully support the HTML5 File API. The new version of the AjaxFileUpload control can display upload progress in the case of all browsers. If a browser does not fully support the HTML5 File API then the browser polls the server every few seconds with an Ajax request to determine the percentage of the file that has been uploaded. This technique of displaying progress works with any browser which supports making Ajax requests. There is one catch. Be warned that this new feature only works with the .NET 4.0 and .NET 4.5 versions of the AjaxControlToolkit. To show upload progress, we are taking advantage of the new ASP.NET HttpRequest.GetBufferedInputStream() and HttpRequest.GetBufferlessInputStream() methods which are not supported by .NET 3.5. For example, here is what the Network tab looks like when you use the AjaxFileUpload with Microsoft Internet Explorer: Here’s what the requests in the Network tab look like: GET /WebForm1.aspx?contextKey={DA8BEDC8-B952-4d5d-8CC2-59FE922E2923}&poll=1&guid=9206FF94-76F9-B197-D1BC-EA9AD282806B HTTP/1.1 Notice that each request includes a poll=1 parameter. This parameter indicates that this is a polling request to get the size of the file buffered on the server. Here’s what the response body of a request looks like when about 20% of a file has been uploaded: Buffering to a Temporary File When you upload a file using the AjaxFileUpload control, the file upload is buffered to a temporary file located at Path.GetTempPath(). When you call the SaveAs() method, as we did in the sample page above, the temporary file is copied to a new file and then the temporary file is deleted. If you don’t call the SaveAs() method, then you must ensure that the temporary file gets deleted yourself. For example, if you want to save the file to a database then you will never call the SaveAs() method and you are responsible for deleting the file. The easiest way to delete the temporary file is to call the AjaxFileUploadEventArgs.DeleteTemporaryData() method in the UploadComplete handler: protected void AjaxFileUpload1_UploadComplete(object sender, AjaxControlToolkit.AjaxFileUploadEventArgs e) { // Save uploaded file to a database table e.DeleteTemporaryData(); } You also can call the static AjaxFileUpload.CleanAllTemporaryData() method to delete all temporary data and not only the temporary data related to the current file upload. For example, you might want to call this method on application start to ensure that all temporary data is removed whenever your application restarts. A Better MaskedEdit Extender This release of the Ajax Control Toolkit contains bug fixes for the top-voted issues related to the MaskedEdit control. We closed over 25 MaskedEdit issues. Here is a complete list of the issues addressed with this release: · 17302 MaskedEditExtender MaskType=Date, Mask=99/99/99 Undefined JS Error · 11758 MaskedEdit causes error in JScript when working with 2-digits year · 18810 Maskededitextender/validator Date validation issue · 23236 MaskEditValidator does not work with date input using format dd/mm/yyyy · 23042 Webkit based browsers (Safari, Chrome) and MaskedEditExtender · 26685 MaskedEditExtender@(ClearMaskOnLostFocus=false) adds a zero character when you each focused to target textbox · 16109 MaskedEditExtender: Negative amount, followed by decimal, sets value to positive · 11522 MaskEditExtender of AjaxtoolKit-1.0.10618.0 does not work properly for Hungarian Culture · 25988 MaskedEditExtender – CultureName (HU-hu) > DateSeparator · 23221 MaskedEditExtender date separator problem · 15233 Day and month swap in Dynamic user control · 15492 MaskedEditExtender with ClearMaskOnLostFocus and with MaskedEditValidator with ClientValidationFunction · 9389 MaskedEditValidator – when on no entry · 11392 MaskedEdit Number format messed up · 11819 MaskedEditExtender erases all values beyond first comma separtor · 13423 MaskedEdit(Extender/Validator) combo problem · 16111 MaskedEditValidator cannot validate date with DayMonthYear in UserDateFormat of MaskedEditExtender · 10901 MaskedEdit: The months and date fields swap values when you hit submit if UserDateFormat is set. · 15190 MaskedEditValidator can’t make use of MaskedEditExtender’s UserDateFormat property · 13898 MaskedEdit Extender with custom date type mask gives javascript error · 14692 MaskedEdit error in “yy/MM/dd” format. · 16186 MaskedEditExtender does not handle century properly in a date mask · 26456 MaskedEditBehavior. ConvFmtTime : function(input,loadFirst) fails if this._CultureAMPMPlaceholder == “” · 21474 Error on MaskedEditExtender working with number format · 23023 MaskedEditExtender’s ClearMaskOnLostFocus property causes problems for MaskedEditValidator when set to false · 13656 MaskedEditValidator Min/Max Date value issue Conclusion This latest release of the Ajax Control Toolkit required many hours of work by a team of talented developers. I want to thank the members of the Superexpert team for the long hours which they put into this release.

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  • Add collison detection to enemy sprites?

    - by xBroak
    i'd like to add the same collision detection used by the player sprite to the enemy sprites or 'creeps' ive added all the relevant code I can see yet collisons are still not being detected and handled, please find below the class, I have no idea what is wrong currently, the list of walls to collide with is 'wall_list' import pygame import pauseScreen as dm import re from pygame.sprite import Sprite from pygame import Rect, Color from random import randint, choice from vec2d import vec2d from simpleanimation import SimpleAnimation import displattxt black = (0,0,0) white = (255,255,255) blue = (0,0,255) green = (101,194,151) global currentEditTool currentEditTool = "Tree" global editMap editMap = False open('MapMaker.txt', 'w').close() def draw_background(screen, tile_img): screen.fill(black) img_rect = tile_img.get_rect() global rect rect = img_rect nrows = int(screen.get_height() / img_rect.height) + 1 ncols = int(screen.get_width() / img_rect.width) + 1 for y in range(nrows): for x in range(ncols): img_rect.topleft = (x * img_rect.width, y * img_rect.height) screen.blit(tile_img, img_rect) def changeTool(): if currentEditTool == "Tree": None elif currentEditTool == "Rock": None def pauseGame(): red = 255, 0, 0 green = 0,255, 0 blue = 0, 0,255 screen.fill(black) pygame.display.update() if editMap == False: choose = dm.dumbmenu(screen, [ 'Resume', 'Enable Map Editor', 'Quit Game'], 64,64,None,32,1.4,green,red) if choose == 0: print("hi") elif choose ==1: global editMap editMap = True elif choose ==2: print("bob") elif choose ==3: print("bob") elif choose ==4: print("bob") else: None else: choose = dm.dumbmenu(screen, [ 'Resume', 'Disable Map Editor', 'Quit Game'], 64,64,None,32,1.4,green,red) if choose == 0: print("Resume") elif choose ==1: print("Dis ME") global editMap editMap = False elif choose ==2: print("bob") elif choose ==3: print("bob") elif choose ==4: print("bob") else: None class Wall(pygame.sprite.Sprite): # Constructor function def __init__(self,x,y,width,height): pygame.sprite.Sprite.__init__(self) self.image = pygame.Surface([width, height]) self.image.fill(green) self.rect = self.image.get_rect() self.rect.y = y self.rect.x = x class insertTree(pygame.sprite.Sprite): def __init__(self,x,y,width,height, typ): pygame.sprite.Sprite.__init__(self) self.image = pygame.image.load("images/map/tree.png").convert() self.image.set_colorkey(white) self.rect = self.image.get_rect() self.rect.y = y self.rect.x = x class insertRock(pygame.sprite.Sprite): def __init__(self,x,y,width,height, typ): pygame.sprite.Sprite.__init__(self) self.image = pygame.image.load("images/map/rock.png").convert() self.image.set_colorkey(white) self.rect = self.image.get_rect() self.rect.y = y self.rect.x = x class Creep(pygame.sprite.Sprite): """ A creep sprite that bounces off walls and changes its direction from time to time. """ change_x=0 change_y=0 def __init__( self, screen, creep_image, explosion_images, field, init_position, init_direction, speed): """ Create a new Creep. screen: The screen on which the creep lives (must be a pygame Surface object, such as pygame.display) creep_image: Image (surface) object for the creep explosion_images: A list of image objects for the explosion animation. field: A Rect specifying the 'playing field' boundaries. The Creep will bounce off the 'walls' of this field. init_position: A vec2d or a pair specifying the initial position of the creep on the screen. init_direction: A vec2d or a pair specifying the initial direction of the creep. Must have an angle that is a multiple of 45 degres. speed: Creep speed, in pixels/millisecond (px/ms) """ Sprite.__init__(self) self.screen = screen self.speed = speed self.field = field self.rect = creep_image.get_rect() # base_image holds the original image, positioned to # angle 0. # image will be rotated. # self.base_image = creep_image self.image = self.base_image self.explosion_images = explosion_images # A vector specifying the creep's position on the screen # self.pos = vec2d(init_position) # The direction is a normalized vector # self.direction = vec2d(init_direction).normalized() self.state = Creep.ALIVE self.health = 15 def is_alive(self): return self.state in (Creep.ALIVE, Creep.EXPLODING) def changespeed(self,x,y): self.change_x+=x self.change_y+=y def update(self, time_passed, walls): """ Update the creep. time_passed: The time passed (in ms) since the previous update. """ if self.state == Creep.ALIVE: # Maybe it's time to change the direction ? # self._change_direction(time_passed) # Make the creep point in the correct direction. # Since our direction vector is in screen coordinates # (i.e. right bottom is 1, 1), and rotate() rotates # counter-clockwise, the angle must be inverted to # work correctly. # self.image = pygame.transform.rotate( self.base_image, -self.direction.angle) # Compute and apply the displacement to the position # vector. The displacement is a vector, having the angle # of self.direction (which is normalized to not affect # the magnitude of the displacement) # displacement = vec2d( self.direction.x * self.speed * time_passed, self.direction.y * self.speed * time_passed) self.pos += displacement # When the image is rotated, its size is changed. # We must take the size into account for detecting # collisions with the walls. # self.image_w, self.image_h = self.image.get_size() bounds_rect = self.field.inflate( -self.image_w, -self.image_h) if self.pos.x < bounds_rect.left: self.pos.x = bounds_rect.left self.direction.x *= -1 elif self.pos.x > bounds_rect.right: self.pos.x = bounds_rect.right self.direction.x *= -1 elif self.pos.y < bounds_rect.top: self.pos.y = bounds_rect.top self.direction.y *= -1 elif self.pos.y > bounds_rect.bottom: self.pos.y = bounds_rect.bottom self.direction.y *= -1 # collision detection old_x=bounds_rect.left new_x=old_x+self.direction.x bounds_rect.left = new_x # hit a wall? collide = pygame.sprite.spritecollide(self, walls, False) if collide: # yes bounds_rect.left=old_x old_y=self.pos.y new_y=old_y+self.direction.y self.pos.y = new_y collide = pygame.sprite.spritecollide(self, walls, False) if collide: # yes self.pos.y=old_y elif self.state == Creep.EXPLODING: if self.explode_animation.active: self.explode_animation.update(time_passed) else: self.state = Creep.DEAD self.kill() elif self.state == Creep.DEAD: pass #------------------ PRIVATE PARTS ------------------# # States the creep can be in. # # ALIVE: The creep is roaming around the screen # EXPLODING: # The creep is now exploding, just a moment before dying. # DEAD: The creep is dead and inactive # (ALIVE, EXPLODING, DEAD) = range(3) _counter = 0 def _change_direction(self, time_passed): """ Turn by 45 degrees in a random direction once per 0.4 to 0.5 seconds. """ self._counter += time_passed if self._counter > randint(400, 500): self.direction.rotate(45 * randint(-1, 1)) self._counter = 0 def _point_is_inside(self, point): """ Is the point (given as a vec2d) inside our creep's body? """ img_point = point - vec2d( int(self.pos.x - self.image_w / 2), int(self.pos.y - self.image_h / 2)) try: pix = self.image.get_at(img_point) return pix[3] > 0 except IndexError: return False def _decrease_health(self, n): """ Decrease my health by n (or to 0, if it's currently less than n) """ self.health = max(0, self.health - n) if self.health == 0: self._explode() def _explode(self): """ Starts the explosion animation that ends the Creep's life. """ self.state = Creep.EXPLODING pos = ( self.pos.x - self.explosion_images[0].get_width() / 2, self.pos.y - self.explosion_images[0].get_height() / 2) self.explode_animation = SimpleAnimation( self.screen, pos, self.explosion_images, 100, 300) global remainingCreeps remainingCreeps-=1 if remainingCreeps == 0: print("all dead") def draw(self): """ Blit the creep onto the screen that was provided in the constructor. """ if self.state == Creep.ALIVE: # The creep image is placed at self.pos. To allow for # smooth movement even when the creep rotates and the # image size changes, its placement is always # centered. # self.draw_rect = self.image.get_rect().move( self.pos.x - self.image_w / 2, self.pos.y - self.image_h / 2) self.screen.blit(self.image, self.draw_rect) # The health bar is 15x4 px. # health_bar_x = self.pos.x - 7 health_bar_y = self.pos.y - self.image_h / 2 - 6 self.screen.fill( Color('red'), (health_bar_x, health_bar_y, 15, 4)) self.screen.fill( Color('green'), ( health_bar_x, health_bar_y, self.health, 4)) elif self.state == Creep.EXPLODING: self.explode_animation.draw() elif self.state == Creep.DEAD: pass def mouse_click_event(self, pos): """ The mouse was clicked in pos. """ if self._point_is_inside(vec2d(pos)): self._decrease_health(3) #begin new player class Player(pygame.sprite.Sprite): change_x=0 change_y=0 frame = 0 def __init__(self,x,y): pygame.sprite.Sprite.__init__(self) # LOAD PLATER IMAGES # Set height, width self.images = [] for i in range(1,17): img = pygame.image.load("images/player/" + str(i)+".png").convert() #player images img.set_colorkey(white) self.images.append(img) self.image = self.images[0] self.rect = self.image.get_rect() self.rect.y = y self.rect.x = x self.health = 15 self.image_w, self.image_h = self.image.get_size() health_bar_x = self.rect.x - 7 health_bar_y = self.rect.y - self.image_h / 2 - 6 screen.fill( Color('red'), (health_bar_x, health_bar_y, 15, 4)) screen.fill( Color('green'), ( health_bar_x, health_bar_y, self.health, 4)) def changespeed(self,x,y): self.change_x+=x self.change_y+=y def _decrease_health(self, n): """ Decrease my health by n (or to 0, if it's currently less than n) """ self.health = max(0, self.health - n) if self.health == 0: self._explode() def update(self,walls): # collision detection old_x=self.rect.x new_x=old_x+self.change_x self.rect.x = new_x # hit a wall? collide = pygame.sprite.spritecollide(self, walls, False) if collide: # yes self.rect.x=old_x old_y=self.rect.y new_y=old_y+self.change_y self.rect.y = new_y collide = pygame.sprite.spritecollide(self, walls, False) if collide: # yes self.rect.y=old_y # right to left if self.change_x < 0: self.frame += 1 if self.frame > 3*4: self.frame = 0 # Grab the image, divide by 4 # every 4 frames. self.image = self.images[self.frame//4] # Move left to right. # images 4...7 instead of 0...3. if self.change_x > 0: self.frame += 1 if self.frame > 3*4: self.frame = 0 self.image = self.images[self.frame//4+4] if self.change_y > 0: self.frame += 1 if self.frame > 3*4: self.frame = 0 self.image = self.images[self.frame//4+4+4] if self.change_y < 0: self.frame += 1 if self.frame > 3*4: self.frame = 0 self.image = self.images[self.frame//4+4+4+4] score = 0 # initialize pyGame pygame.init() # 800x600 sized screen global screen screen = pygame.display.set_mode([800, 600]) screen.fill(black) #bg_tile_img = pygame.image.load('images/map/grass.png').convert_alpha() #draw_background(screen, bg_tile_img) #pygame.display.flip() # Set title pygame.display.set_caption('Test') #background = pygame.Surface(screen.get_size()) #background = background.convert() #background.fill(black) # Create the player player = Player( 50,50 ) player.rect.x=50 player.rect.y=50 movingsprites = pygame.sprite.RenderPlain() movingsprites.add(player) # Make the walls. (x_pos, y_pos, width, height) global wall_list wall_list=pygame.sprite.RenderPlain() wall=Wall(0,0,10,600) # left wall wall_list.add(wall) wall=Wall(10,0,790,10) # top wall wall_list.add(wall) #wall=Wall(10,200,100,10) # poke wall wall_list.add(wall) wall=Wall(790,0,10,600) #(x,y,thickness, height) wall_list.add(wall) wall=Wall(10,590,790,10) #(x,y,thickness, height) wall_list.add(wall) f = open('MapMaker.txt') num_lines = sum(1 for line in f) print(num_lines) lineCount = 0 with open("MapMaker.txt") as infile: for line in infile: f = open('MapMaker.txt') print(line) coords = line.split(',') #print(coords[0]) #print(coords[1]) #print(coords[2]) #print(coords[3]) #print(coords[4]) if "tree" in line: print("tree in") wall=insertTree(int(coords[0]),int(coords[1]), int(coords[2]),int(coords[3]),coords[4]) wall_list.add(wall) elif "rock" in line: print("rock in") wall=insertRock(int(coords[0]),int(coords[1]), int(coords[2]),int(coords[3]),coords[4] ) wall_list.add(wall) width = 20 height = 540 height = height - 48 for i in range(0,23): width = width + 32 name = insertTree(width,540,790,10,"tree") #wall_list.add(name) name = insertTree(width,height,690,10,"tree") #wall_list.add(name) CREEP_SPAWN_TIME = 200 # frames creep_spawn = CREEP_SPAWN_TIME clock = pygame.time.Clock() bg_tile_img = pygame.image.load('images/map/grass.png').convert() img_rect = bg_tile_img FIELD_RECT = Rect(50, 50, 700, 500) CREEP_FILENAMES = [ 'images/player/1.png', 'images/player/1.png', 'images/player/1.png'] N_CREEPS = 3 creep_images = [ pygame.image.load(filename).convert_alpha() for filename in CREEP_FILENAMES] explosion_img = pygame.image.load('images/map/tree.png').convert_alpha() explosion_images = [ explosion_img, pygame.transform.rotate(explosion_img, 90)] creeps = pygame.sprite.RenderPlain() done = False #bg_tile_img = pygame.image.load('images/map/grass.png').convert() #draw_background(screen, bg_tile_img) totalCreeps = 0 remainingCreeps = 3 while done == False: creep_images = pygame.image.load("images/player/1.png").convert() creep_images.set_colorkey(white) draw_background(screen, bg_tile_img) if len(creeps) != N_CREEPS: if totalCreeps < N_CREEPS: totalCreeps = totalCreeps + 1 print(totalCreeps) creeps.add( Creep( screen=screen, creep_image=creep_images, explosion_images=explosion_images, field=FIELD_RECT, init_position=( randint(FIELD_RECT.left, FIELD_RECT.right), randint(FIELD_RECT.top, FIELD_RECT.bottom)), init_direction=(choice([-1, 1]), choice([-1, 1])), speed=0.01)) for creep in creeps: creep.update(60,wall_list) creep.draw() for event in pygame.event.get(): if event.type == pygame.QUIT: done=True if event.type == pygame.KEYDOWN: if event.key == pygame.K_LEFT: player.changespeed(-2,0) creep.changespeed(-2,0) if event.key == pygame.K_RIGHT: player.changespeed(2,0) creep.changespeed(2,0) if event.key == pygame.K_UP: player.changespeed(0,-2) creep.changespeed(0,-2) if event.key == pygame.K_DOWN: player.changespeed(0,2) creep.changespeed(0,2) if event.key == pygame.K_ESCAPE: pauseGame() if event.key == pygame.K_1: global currentEditTool currentEditTool = "Tree" changeTool() if event.key == pygame.K_2: global currentEditTool currentEditTool = "Rock" changeTool() if event.type == pygame.KEYUP: if event.key == pygame.K_LEFT: player.changespeed(2,0) creep.changespeed(2,0) if event.key == pygame.K_RIGHT: player.changespeed(-2,0) creep.changespeed(-2,0) if event.key == pygame.K_UP: player.changespeed(0,2) creep.changespeed(0,2) if event.key == pygame.K_DOWN: player.changespeed(0,-2) creep.changespeed(0,-2) if event.type == pygame.MOUSEBUTTONDOWN and pygame.mouse.get_pressed()[0]: for creep in creeps: creep.mouse_click_event(pygame.mouse.get_pos()) if editMap == True: x,y = pygame.mouse.get_pos() if currentEditTool == "Tree": name = insertTree(x-10,y-25, 10 , 10, "tree") wall_list.add(name) wall_list.draw(screen) f = open('MapMaker.txt', "a+") image = pygame.image.load("images/map/tree.png").convert() screen.blit(image, (30,10)) pygame.display.flip() f.write(str(x) + "," + str(y) + ",790,10, tree\n") #f.write("wall=insertTree(" + str(x) + "," + str(y) + ",790,10)\nwall_list.add(wall)\n") elif currentEditTool == "Rock": name = insertRock(x-10,y-25, 10 , 10,"rock") wall_list.add(name) wall_list.draw(screen) f = open('MapMaker.txt', "a+") f.write(str(x) + "," + str(y) + ",790,10,rock\n") #f.write("wall=insertRock(" + str(x) + "," + str(y) + ",790,10)\nwall_list.add(wall)\n") else: None #pygame.display.flip() player.update(wall_list) movingsprites.draw(screen) wall_list.draw(screen) pygame.display.flip() clock.tick(60) pygame.quit()

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  • Announcing the June 2012 Release of the Ajax Control Toolkit

    - by Stephen.Walther
    I’m excited to announce the June 2012 release of the Ajax Control Toolkit. You can download the new release by visiting http://AjaxControlToolkit.CodePlex.com or (better) download the new release with NuGet: Install-Package AjaxControlToolkit The Ajax Control Toolkit continues to be super popular. The previous release (May 2012) had over 87,000 downloads from CodePlex.com and over 16,000 downloads from NuGet. That’s over 100,000 downloads in less than 2 months. Security Improvements for the HtmlEditorExtender Unfortunately, in the previous release, we made the HtmlEditorExtender too secure! We upgraded the version of the Microsoft Anti-Cross Site Scripting Library included in the Ajax Control Toolkit to the latest version (version 4.2.1) and the latest version turned out to be way too aggressive about stripping HTML. It not only strips dangerous tags such as <script> tags, it also strips innocent tags such as <b> tags. When the latest version of the Microsoft Anti-Cross Site Scripting Library is used with the HtmlEditorExtender, the library strips all rich content from the HtmlEditorExtender control which defeats the purpose of using the control. Therefore, we had to find a replacement for the Microsoft Anti-Cross Site Scripting Library. In this release, we’ve created a new HTML sanitizer built on the HTML Agility Pack. If you were using the AntiXssSanitizerProvider then you will need to substitute the HtmlAgilityPackSanitizerProvider. In particular, you need to modify the sanitizer sections in your Web.config file like this: <configuration> <configSections> <sectionGroup name="system.web"> <section name="sanitizer" requirePermission="false" type="AjaxControlToolkit.Sanitizer.ProviderSanitizerSection, AjaxControlToolkit" /> </sectionGroup> </configSections> <system.web> <sanitizer defaultProvider="HtmlAgilityPackSanitizerProvider"> <providers> <add name="HtmlAgilityPackSanitizerProvider" type="AjaxControlToolkit.Sanitizer.HtmlAgilityPackSanitizerProvider"></add> </providers> </sanitizer> </system.web> </configuration> We made one other backwards-breaking change to improve the security of the HtmlEditorExtender. We want to make sure that users don’t accidently use the HtmlEditorExtender without an HTML sanitizer by accident. Therefore, if you don’t configure a HTML sanitizer provider in the web.config file then you’ll get the following error: If you really want to use the HtmlEditorExtender without using an HTML sanitizer – for example, you are using the HtmlEditorExtender for an Intranet application and you trust all of your fellow employees – then you can explicitly indicate that you don’t want to enable HTML sanitization by setting the EnableSanitization property to false like this: <ajaxToolkit:HtmlEditorExtender TargetControlID="txtComments" EnableSanitization="false" runat="server" /> Please don’t ever set the EnableSanitization property to false for a public website. If you disable HTML sanitization then you are making your website an easy target for Cross-Site Scripting attacks. Lots of Fixes for the ComboBox Control In the latest release, we also made several important bug fixes and feature enhancements to the ComboBox control. Here’s the list of issues that we fixed: 22930 — ComboBox doesn’t close its drop down list when losing input focus to another ComboBox control 23140 — ComboBox Issues – Delete, Backspace, Period 23142 — ComboxBox SelectedIndex = -1 does not clear text 24440 — ComboBox postback on enter 25295 — ComboBox problems when container is hidden at page load 25469 — ComboBox – MaxLength ignored 26686 — Backspace and Delete exception when optionList is null 27148 — Combobox breaks if ClientIDMode is static Fixes to Other Controls In this release, we also made bug fixes and enhancements to the UpdatePanelAnimation, Tabs, and Seadragon controls: 21310 — OnUpdated animation starts before OnUpdating has finished 26690 — Seadragon Control’s openTileSource() method doesn’t work (with fix) Title is required We also fixed an issue with the Tabs control which would result in an InvalidOperation exception. Summary I want to thank the Superexpert team for the hard work that they put into this release. In particular, I want to thank them for their effort in researching, building, and writing unit tests for the HtmlAgilityPack HTML sanitizer.

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  • Metro: Query Selectors

    - by Stephen.Walther
    The goal of this blog entry is to explain how to perform queries using selectors when using the WinJS library. In particular, you learn how to use the WinJS.Utilities.query() method and the QueryCollection class to retrieve and modify the elements of an HTML document. Introduction to Selectors When you are building a Web application, you need some way of easily retrieving elements from an HTML document. For example, you might want to retrieve all of the input elements which have a certain class. Or, you might want to retrieve the one and only element with an id of favoriteColor. The standard way of retrieving elements from an HTML document is by using a selector. Anyone who has ever created a Cascading Style Sheet has already used selectors. You use selectors in Cascading Style Sheets to apply formatting rules to elements in a document. For example, the following Cascading Style Sheet rule changes the background color of every INPUT element with a class of .required in a document to the color red: input.red { background-color: red } The “input.red” part is the selector which matches all INPUT elements with a class of red. The W3C standard for selectors (technically, their recommendation) is entitled “Selectors Level 3” and the standard is located here: http://www.w3.org/TR/css3-selectors/ Selectors are not only useful for adding formatting to the elements of a document. Selectors are also useful when you need to apply behavior to the elements of a document. For example, you might want to select a particular BUTTON element with a selector and add a click handler to the element so that something happens whenever you click the button. Selectors are not specific to Cascading Style Sheets. You can use selectors in your JavaScript code to retrieve elements from an HTML document. jQuery is famous for its support for selectors. Using jQuery, you can use a selector to retrieve matching elements from a document and modify the elements. The WinJS library enables you to perform the same types of queries as jQuery using the W3C selector syntax. Performing Queries with the WinJS.Utilities.query() Method When using the WinJS library, you perform a query using a selector by using the WinJS.Utilities.query() method.  The following HTML document contains a BUTTON and a DIV element: <!DOCTYPE html> <html> <head> <meta charset="utf-8"> <title>Application1</title> <!-- WinJS references --> <link href="//Microsoft.WinJS.0.6/css/ui-dark.css" rel="stylesheet"> <script src="//Microsoft.WinJS.0.6/js/base.js"></script> <script src="//Microsoft.WinJS.0.6/js/ui.js"></script> <!-- Application1 references --> <link href="/css/default.css" rel="stylesheet"> <script src="/js/default.js"></script> </head> <body> <button>Click Me!</button> <div style="display:none"> <h1>Secret Message</h1> </div> </body> </html> The document contains a reference to the following JavaScript file named \js\default.js: (function () { "use strict"; var app = WinJS.Application; app.onactivated = function (eventObject) { if (eventObject.detail.kind === Windows.ApplicationModel.Activation.ActivationKind.launch) { WinJS.Utilities.query("button").listen("click", function () { WinJS.Utilities.query("div").clearStyle("display"); }); } }; app.start(); })(); The default.js script uses the WinJS.Utilities.query() method to retrieve all of the BUTTON elements in the page. The listen() method is used to wire an event handler to the BUTTON click event. When you click the BUTTON, the secret message contained in the hidden DIV element is displayed. The clearStyle() method is used to remove the display:none style attribute from the DIV element. Under the covers, the WinJS.Utilities.query() method uses the standard querySelectorAll() method. This means that you can use any selector which is compatible with the querySelectorAll() method when using the WinJS.Utilities.query() method. The querySelectorAll() method is defined in the W3C Selectors API Level 1 standard located here: http://www.w3.org/TR/selectors-api/ Unlike the querySelectorAll() method, the WinJS.Utilities.query() method returns a QueryCollection. We talk about the methods of the QueryCollection class below. Retrieving a Single Element with the WinJS.Utilities.id() Method If you want to retrieve a single element from a document, instead of matching a set of elements, then you can use the WinJS.Utilities.id() method. For example, the following line of code changes the background color of an element to the color red: WinJS.Utilities.id("message").setStyle("background-color", "red"); The statement above matches the one and only element with an Id of message. For example, the statement matches the following DIV element: <div id="message">Hello!</div> Notice that you do not use a hash when matching a single element with the WinJS.Utilities.id() method. You would need to use a hash when using the WinJS.Utilities.query() method to do the same thing like this: WinJS.Utilities.query("#message").setStyle("background-color", "red"); Under the covers, the WinJS.Utilities.id() method calls the standard document.getElementById() method. The WinJS.Utilities.id() method returns the result as a QueryCollection. If no element matches the identifier passed to WinJS.Utilities.id() then you do not get an error. Instead, you get a QueryCollection with no elements (length=0). Using the WinJS.Utilities.children() method The WinJS.Utilities.children() method enables you to retrieve a QueryCollection which contains all of the children of a DOM element. For example, imagine that you have a DIV element which contains children DIV elements like this: <div id="discussContainer"> <div>Message 1</div> <div>Message 2</div> <div>Message 3</div> </div> You can use the following code to add borders around all of the child DIV element and not the container DIV element: var discussContainer = WinJS.Utilities.id("discussContainer").get(0); WinJS.Utilities.children(discussContainer).setStyle("border", "2px dashed red");   It is important to understand that the WinJS.Utilities.children() method only works with a DOM element and not a QueryCollection. Notice that the get() method is used to retrieve the DOM element which represents the discussContainer. Working with the QueryCollection Class Both the WinJS.Utilities.query() method and the WinJS.Utilities.id() method return an instance of the QueryCollection class. The QueryCollection class derives from the base JavaScript Array class and adds several useful methods for working with HTML elements: addClass(name) – Adds a class to every element in the QueryCollection. clearStyle(name) – Removes a style from every element in the QueryCollection. conrols(ctor, options) – Enables you to create controls. get(index) – Retrieves the element from the QueryCollection at the specified index. getAttribute(name) – Retrieves the value of an attribute for the first element in the QueryCollection. hasClass(name) – Returns true if the first element in the QueryCollection has a certain class. include(items) – Includes a collection of items in the QueryCollection. listen(eventType, listener, capture) – Adds an event listener to every element in the QueryCollection. query(query) – Performs an additional query on the QueryCollection and returns a new QueryCollection. removeClass(name) – Removes a class from the every element in the QueryCollection. removeEventListener(eventType, listener, capture) – Removes an event listener from every element in the QueryCollection. setAttribute(name, value) – Adds an attribute to every element in the QueryCollection. setStyle(name, value) – Adds a style attribute to every element in the QueryCollection. template(templateElement, data, renderDonePromiseContract) – Renders a template using the supplied data.  toggleClass(name) – Toggles the specified class for every element in the QueryCollection. Because the QueryCollection class derives from the base Array class, it also contains all of the standard Array methods like forEach() and slice(). Summary In this blog post, I’ve described how you can perform queries using selectors within a Windows Metro Style application written with JavaScript. You learned how to return an instance of the QueryCollection class by using the WinJS.Utilities.query(), WinJS.Utilities.id(), and WinJS.Utilities.children() methods. You also learned about the methods of the QueryCollection class.

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  • September 2012 Release of the Ajax Control Toolkit

    - by Stephen.Walther
    I’m excited to announce the September 2012 release of the Ajax Control Toolkit! This is the first release of the Ajax Control Toolkit which supports the .NET 4.5 framework. We also continue to support ASP.NET 3.5 and ASP.NET 4.0. With this release, we’ve made several important bug fixes. The Superexpert team focused on fixing the highest voted issues associated with the CascadingDropDown control. I’ve created a list of these bug fixes later in this blog post. You can download the latest release of the Ajax Control Toolkit by visiting the following page at CodePlex: http://AjaxControlToolkit.CodePlex.com Alternatively, you can install the latest version of the Ajax Control Toolkit using NuGet by firing off the following command from the Package Manager Console: Install-Package AjaxControlToolkit Using the Ajax Control Toolkit with ASP.NET 4.5 Let me walk through the steps for using the Ajax Control Toolkit with ASP.NET 4.5. First, I’ll create a new ASP.NET 4.5 website with Visual Studio 2012. I’ll create the new website with the ASP.NET Web Forms Application template: When you create a new ASP.NET 4.5 site with the ASP.NET Web Forms Application template, you get a starter website. If you run the site, then you get a page with default content: Let me show you how you can add the Ajax Control Toolkit Calendar control to the homepage of this starter site. The first step is to use NuGet to install the Ajax Control Toolkit. Right-click the References folder in the Solution Explorer window and select the menu option Manage NuGet Packages. In the Manage NuGet Packages dialog, use the search box to search for the Ajax Control Toolkit (enter “AjaxControlToolkit”). After you find it, click the Install button to add the Ajax Control Toolkit to your project. That’s all you have to do to install the Ajax Control Toolkit! Now we are ready to start using the Ajax Control Toolkit controls. Open the default.aspx page so we can modify the contents of the page. Erase everything contained in the Content control with the ID of BodyContent. After erasing the content, declare the following two controls: <asp:TextBox ID="vacationDate" runat="server" /> <ajaxToolkit:CalendarExtender TargetControlID="vacationDate" runat="server" /> The first control is a standard ASP.NET TextBox control and the second control is an Ajax Control Toolkit Calendar control. You should get intellisense as you type out the Ajax Control Toolkit Calendar control. If you don’t, then close and re-open the Default.aspx page. Now, let’s run our app. Hit the F5 button or select Debug, Start Debugging from the Visual Studio menu. You will get the error message “MsAjaxBundle is not a valid script name”. Don’t despair! We need to update the Master Page so it uses the ToolkitScriptManager instead of the default ScriptManager. Open the Site.Master file and find where the ScriptManager is declared. The ScriptManager should look like this: <asp:ScriptManager runat="server"> <Scripts> <%--Framework Scripts--%> <asp:ScriptReference Name="MsAjaxBundle" /> <asp:ScriptReference Name="jquery" /> <asp:ScriptReference Name="jquery.ui.combined" /> <asp:ScriptReference Name="WebForms.js" Assembly="System.Web" Path="~/Scripts/WebForms/WebForms.js" /> <asp:ScriptReference Name="WebUIValidation.js" Assembly="System.Web" Path="~/Scripts/WebForms/WebUIValidation.js" /> <asp:ScriptReference Name="MenuStandards.js" Assembly="System.Web" Path="~/Scripts/WebForms/MenuStandards.js" /> <asp:ScriptReference Name="GridView.js" Assembly="System.Web" Path="~/Scripts/WebForms/GridView.js" /> <asp:ScriptReference Name="DetailsView.js" Assembly="System.Web" Path="~/Scripts/WebForms/DetailsView.js" /> <asp:ScriptReference Name="TreeView.js" Assembly="System.Web" Path="~/Scripts/WebForms/TreeView.js" /> <asp:ScriptReference Name="WebParts.js" Assembly="System.Web" Path="~/Scripts/WebForms/WebParts.js" /> <asp:ScriptReference Name="Focus.js" Assembly="System.Web" Path="~/Scripts/WebForms/Focus.js" /> <asp:ScriptReference Name="WebFormsBundle" /> <%--Site Scripts--%> </Scripts> </asp:ScriptManager> We need to make three changes to the ScriptManager: 1) We need to replace the asp:ScriptManager with the ajaxToolkit:ToolkitScriptManager 2) We need to remove the MsAjaxBundle bundle from the ScriptReferences 3) We need to remove the Assembly=”System.Web” attributes from the ScriptReferences After you make these three changes, the ToolkitScriptManager should looks like this: <ajaxToolkit:ToolkitScriptManager runat="server"> <Scripts> <%--Framework Scripts--%> <asp:ScriptReference Name="jquery" /> <asp:ScriptReference Name="jquery.ui.combined" /> <asp:ScriptReference Name="WebForms.js" Path="~/Scripts/WebForms/WebForms.js" /> <asp:ScriptReference Name="WebUIValidation.js" Path="~/Scripts/WebForms/WebUIValidation.js" /> <asp:ScriptReference Name="MenuStandards.js" Path="~/Scripts/WebForms/MenuStandards.js" /> <asp:ScriptReference Name="GridView.js" Path="~/Scripts/WebForms/GridView.js" /> <asp:ScriptReference Name="DetailsView.js" Path="~/Scripts/WebForms/DetailsView.js" /> <asp:ScriptReference Name="TreeView.js" Path="~/Scripts/WebForms/TreeView.js" /> <asp:ScriptReference Name="WebParts.js" Path="~/Scripts/WebForms/WebParts.js" /> <asp:ScriptReference Name="Focus.js" Path="~/Scripts/WebForms/Focus.js" /> <asp:ScriptReference Name="WebFormsBundle" /> <%--Site Scripts--%> </Scripts> </ajaxToolkit:ToolkitScriptManager> After we make these changes, the app should run successfully. You’ll get a page which contains a text field. When you click inside the text field, a popup calendar is displayed. Ajax Control Toolkit and jQuery You might have noticed that the ScriptManager includes a reference to jQuery by default. We did not remove that reference when we converted the ScriptManager to a ToolkitScriptManager. You can use the Ajax Control Toolkit and jQuery side-by-side. Here’s how you can modify the Default.aspx page so that it contains two popup calendars. The first popup calendar is created with the Ajax Control Toolkit and the second popup calendar is created with jQuery: <asp:TextBox ID="vacationDate" runat="server" /> <ajaxToolkit:CalendarExtender TargetControlID="vacationDate" runat="server" /> <input id="birthDate" /> <script> $("#birthDate").datepicker(); </script> Before you can start using jQuery UI plugins, you need to complete one more step. You need to add the jQuery UI themes bundle to the HEAD of the Site.Master page like this: <head runat="server"> <meta charset="utf-8" /> <title><%: Page.Title %> - My ASP.NET Application</title> <asp:PlaceHolder runat="server"> <%: Scripts.Render("~/bundles/modernizr") %> </asp:PlaceHolder> <webopt:BundleReference runat="server" Path="~/Content/css" /> <webopt:BundleReference runat="server" Path="~/Content/themes/base/css" /> <link href="~/favicon.ico" rel="shortcut icon" type="image/x-icon" /> <meta name="viewport" content="width=device-width" /> <asp:ContentPlaceHolder runat="server" ID="HeadContent" /> </head> The markup above includes a reference to the jQuery UI themes bundle: <webopt:BundleReference runat="server" Path="~/Content/themes/base/css" /> Now that we have made these changes, we can use the Ajax Control Toolkit and jQuery at the same time. When you run your app, you get two popup calendars. When you click in the first text field, the Ajax Control Toolkit calendar appears. When you click in the second text field, the jQuery UI popup calendar appears: Bug Fixes in this Release We made several important bug fixes with this release of the Ajax Control Toolkit and integrated several Pull Requests contributed by the community. Our primary focus during this sprint was fixing issues with the CascadingDropDown control. We fixed the following issues associated with the CascadingDropDown: · 9490 – Don’t disable dropdowns in CascadingDropDown · 14223 – CascadingDropDown Reset or Setting SelectedValue from WebMethod · 12189 – CascadingDropDown not obeying disabled state of DropDownList · 22942 – CascadingDropDown infinite loop (with solution) · 8671 – CascadingDropdown options is null or undefined · 14407 – CascadingDropDown: populated client event happens too often · 17148 – CascadingDropDown – Add “UseHttpGet” property · 10221 – No NotNull check in CascadingDropDown · 12228 – Provide property for case-insensitive DefaultValue lookup in CascadingDropdown We also fixed the following two issues which are not directly related to the CascadingDropDown control: · 27108 – CalendarExtender: Bug when selecting December shifts to January. · 27041 – Input controls with HTML5 types do not post back in Firefox, Chrome, Safari Finally, we integrated several Pull Requests submitted by the community (Thank you community!): · Added French localized resources for the AjaxFileUpload · Resolved an issue which prevented the AjaxFileUpload control from working with pages that require query string variables. · Extended the AjaxFileUploadEventArgs class to include the current file index in the queue and the total number of files in the queue. · Fixed an issue with TabContainer and TabPanel which caused the OnActiveTabChanged event to fire too often. Summary I’m happy to see the Ajax Control Toolkit move forward into the brave new world of ASP.NET 4.5! In this latest release, we focused on ensuring that the Ajax Control Toolkit works smoothly with ASP.NET 4.5 applications. We also fixed the highest voted bugs associated with the CascadingDropDown control and integrated several Pull Request submitted by the community. Once again, I want to thank the Superexpert team for their hard work on this release!

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  • Metro: Introduction to CSS 3 Grid Layout

    - by Stephen.Walther
    The purpose of this blog post is to provide you with a quick introduction to the new W3C CSS 3 Grid Layout standard. You can use CSS Grid Layout in Metro style applications written with JavaScript to lay out the content of an HTML page. CSS Grid Layout provides you with all of the benefits of using HTML tables for layout without requiring you to actually use any HTML table elements. Doing Page Layouts without Tables Back in the 1990’s, if you wanted to create a fancy website, then you would use HTML tables for layout. For example, if you wanted to create a standard three-column page layout then you would create an HTML table with three columns like this: <table height="100%"> <tr> <td valign="top" width="300px" bgcolor="red"> Left Column, Left Column, Left Column, Left Column, Left Column, Left Column, Left Column, Left Column, Left Column </td> <td valign="top" bgcolor="green"> Middle Column, Middle Column, Middle Column, Middle Column, Middle Column, Middle Column, Middle Column, Middle Column, Middle Column </td> <td valign="top" width="300px" bgcolor="blue"> Right Column, Right Column, Right Column, Right Column, Right Column, Right Column, Right Column, Right Column, Right Column </td> </tr> </table> When the table above gets rendered out to a browser, you end up with the following three-column layout: The width of the left and right columns is fixed – the width of the middle column expands or contracts depending on the width of the browser. Sometime around the year 2005, everyone decided that using tables for layout was a bad idea. Instead of using tables for layout — it was collectively decided by the spirit of the Web — you should use Cascading Style Sheets instead. Why is using HTML tables for layout bad? Using tables for layout breaks the semantics of the TABLE element. A TABLE element should be used only for displaying tabular information such as train schedules or moon phases. Using tables for layout is bad for accessibility (The Web Content Accessibility Guidelines 1.0 is explicit about this) and using tables for layout is bad for separating content from layout (see http://CSSZenGarden.com). Post 2005, anyone who used HTML tables for layout were encouraged to hold their heads down in shame. That’s all well and good, but the problem with using CSS for layout is that it can be more difficult to work with CSS than HTML tables. For example, to achieve a standard three-column layout, you either need to use absolute positioning or floats. Here’s a three-column layout with floats: <style type="text/css"> #container { min-width: 800px; } #leftColumn { float: left; width: 300px; height: 100%; background-color:red; } #middleColumn { background-color:green; height: 100%; } #rightColumn { float: right; width: 300px; height: 100%; background-color:blue; } </style> <div id="container"> <div id="rightColumn"> Right Column, Right Column, Right Column, Right Column, Right Column, Right Column, Right Column, Right Column, Right Column </div> <div id="leftColumn"> Left Column, Left Column, Left Column, Left Column, Left Column, Left Column, Left Column, Left Column, Left Column </div> <div id="middleColumn"> Middle Column, Middle Column, Middle Column, Middle Column, Middle Column, Middle Column, Middle Column, Middle Column, Middle Column </div> </div> The page above contains four DIV elements: a container DIV which contains a leftColumn, middleColumn, and rightColumn DIV. The leftColumn DIV element is floated to the left and the rightColumn DIV element is floated to the right. Notice that the rightColumn DIV appears in the page before the middleColumn DIV – this unintuitive ordering is necessary to get the floats to work correctly (see http://stackoverflow.com/questions/533607/css-three-column-layout-problem). The page above (almost) works with the most recent versions of most browsers. For example, you get the correct three-column layout in both Firefox and Chrome: And the layout mostly works with Internet Explorer 9 except for the fact that for some strange reason the min-width doesn’t work so when you shrink the width of your browser, you can get the following unwanted layout: Notice how the middle column (the green column) bleeds to the left and right. People have solved these issues with more complicated CSS. For example, see: http://matthewjamestaylor.com/blog/holy-grail-no-quirks-mode.htm But, at this point, no one could argue that using CSS is easier or more intuitive than tables. It takes work to get a layout with CSS and we know that we could achieve the same layout more easily using HTML tables. Using CSS Grid Layout CSS Grid Layout is a new W3C standard which provides you with all of the benefits of using HTML tables for layout without the disadvantage of using an HTML TABLE element. In other words, CSS Grid Layout enables you to perform table layouts using pure Cascading Style Sheets. The CSS Grid Layout standard is still in a “Working Draft” state (it is not finalized) and it is located here: http://www.w3.org/TR/css3-grid-layout/ The CSS Grid Layout standard is only supported by Internet Explorer 10 and there are no signs that any browser other than Internet Explorer will support this standard in the near future. This means that it is only practical to take advantage of CSS Grid Layout when building Metro style applications with JavaScript. Here’s how you can create a standard three-column layout using a CSS Grid Layout: <!DOCTYPE html> <html> <head> <style type="text/css"> html, body, #container { height: 100%; padding: 0px; margin: 0px; } #container { display: -ms-grid; -ms-grid-columns: 300px auto 300px; -ms-grid-rows: 100%; } #leftColumn { -ms-grid-column: 1; background-color:red; } #middleColumn { -ms-grid-column: 2; background-color:green; } #rightColumn { -ms-grid-column: 3; background-color:blue; } </style> </head> <body> <div id="container"> <div id="leftColumn"> Left Column, Left Column, Left Column, Left Column, Left Column, Left Column, Left Column, Left Column, Left Column </div> <div id="middleColumn"> Middle Column, Middle Column, Middle Column, Middle Column, Middle Column, Middle Column, Middle Column, Middle Column, Middle Column </div> <div id="rightColumn"> Right Column, Right Column, Right Column, Right Column, Right Column, Right Column, Right Column, Right Column, Right Column </div> </div> </body> </html> When the page above is rendered in Internet Explorer 10, you get a standard three-column layout: The page above contains four DIV elements: a container DIV which contains a leftColumn DIV, middleColumn DIV, and rightColumn DIV. The container DIV is set to Grid display mode with the following CSS rule: #container { display: -ms-grid; -ms-grid-columns: 300px auto 300px; -ms-grid-rows: 100%; } The display property is set to the value “-ms-grid”. This property causes the container DIV to lay out its child elements in a grid. (Notice that you use “-ms-grid” instead of “grid”. The “-ms-“ prefix is used because the CSS Grid Layout standard is still preliminary. This implementation only works with IE10 and it might change before the final release.) The grid columns and rows are defined with the “-ms-grid-columns” and “-ms-grid-rows” properties. The style rule above creates a grid with three columns and one row. The left and right columns are fixed sized at 300 pixels. The middle column sizes automatically depending on the remaining space available. The leftColumn, middleColumn, and rightColumn DIVs are positioned within the container grid element with the following CSS rules: #leftColumn { -ms-grid-column: 1; background-color:red; } #middleColumn { -ms-grid-column: 2; background-color:green; } #rightColumn { -ms-grid-column: 3; background-color:blue; } The “-ms-grid-column” property is used to specify the column associated with the element selected by the style sheet selector. The leftColumn DIV is positioned in the first grid column, the middleColumn DIV is positioned in the second grid column, and the rightColumn DIV is positioned in the third grid column. I find using CSS Grid Layout to be just as intuitive as using an HTML table for layout. You define your columns and rows and then you position different elements within these columns and rows. Very straightforward. Creating Multiple Columns and Rows In the previous section, we created a super simple three-column layout. This layout contained only a single row. In this section, let’s create a slightly more complicated layout which contains more than one row: The following page contains a header row, a content row, and a footer row. The content row contains three columns: <!DOCTYPE html> <html> <head> <style type="text/css"> html, body, #container { height: 100%; padding: 0px; margin: 0px; } #container { display: -ms-grid; -ms-grid-columns: 300px auto 300px; -ms-grid-rows: 100px 1fr 100px; } #header { -ms-grid-column: 1; -ms-grid-column-span: 3; -ms-grid-row: 1; background-color: yellow; } #leftColumn { -ms-grid-column: 1; -ms-grid-row: 2; background-color:red; } #middleColumn { -ms-grid-column: 2; -ms-grid-row: 2; background-color:green; } #rightColumn { -ms-grid-column: 3; -ms-grid-row: 2; background-color:blue; } #footer { -ms-grid-column: 1; -ms-grid-column-span: 3; -ms-grid-row: 3; background-color: orange; } </style> </head> <body> <div id="container"> <div id="header"> Header, Header, Header </div> <div id="leftColumn"> Left Column, Left Column, Left Column, Left Column, Left Column, Left Column, Left Column, Left Column, Left Column </div> <div id="middleColumn"> Middle Column, Middle Column, Middle Column, Middle Column, Middle Column, Middle Column, Middle Column, Middle Column, Middle Column </div> <div id="rightColumn"> Right Column, Right Column, Right Column, Right Column, Right Column, Right Column, Right Column, Right Column, Right Column </div> <div id="footer"> Footer, Footer, Footer </div> </div> </body> </html> In the page above, the grid layout is created with the following rule which creates a grid with three rows and three columns: #container { display: -ms-grid; -ms-grid-columns: 300px auto 300px; -ms-grid-rows: 100px 1fr 100px; } The header is created with the following rule: #header { -ms-grid-column: 1; -ms-grid-column-span: 3; -ms-grid-row: 1; background-color: yellow; } The header is positioned in column 1 and row 1. Furthermore, notice that the “-ms-grid-column-span” property is used to span the header across three columns. CSS Grid Layout and Fractional Units When you use CSS Grid Layout, you can take advantage of fractional units. Fractional units provide you with an easy way of dividing up remaining space in a page. Imagine, for example, that you want to create a three-column page layout. You want the size of the first column to be fixed at 200 pixels and you want to divide the remaining space among the remaining three columns. The width of the second column is equal to the combined width of the third and fourth columns. The following CSS rule creates four columns with the desired widths: #container { display: -ms-grid; -ms-grid-columns: 200px 2fr 1fr 1fr; -ms-grid-rows: 1fr; } The fr unit represents a fraction. The grid above contains four columns. The second column is two times the size (2fr) of the third (1fr) and fourth (1fr) columns. When you use the fractional unit, the remaining space is divided up using fractional amounts. Notice that the single row is set to a height of 1fr. The single grid row gobbles up the entire vertical space. Here’s the entire HTML page: <!DOCTYPE html> <html> <head> <style type="text/css"> html, body, #container { height: 100%; padding: 0px; margin: 0px; } #container { display: -ms-grid; -ms-grid-columns: 200px 2fr 1fr 1fr; -ms-grid-rows: 1fr; } #firstColumn { -ms-grid-column: 1; background-color:red; } #secondColumn { -ms-grid-column: 2; background-color:green; } #thirdColumn { -ms-grid-column: 3; background-color:blue; } #fourthColumn { -ms-grid-column: 4; background-color:orange; } </style> </head> <body> <div id="container"> <div id="firstColumn"> First Column, First Column, First Column </div> <div id="secondColumn"> Second Column, Second Column, Second Column </div> <div id="thirdColumn"> Third Column, Third Column, Third Column </div> <div id="fourthColumn"> Fourth Column, Fourth Column, Fourth Column </div> </div> </body> </html>   Summary There is more in the CSS 3 Grid Layout standard than discussed in this blog post. My goal was to describe the basics. If you want to learn more than you can read through the entire standard at http://www.w3.org/TR/css3-grid-layout/ In this blog post, I described some of the difficulties that you might encounter when attempting to replace HTML tables with Cascading Style Sheets when laying out a web page. I explained how you can take advantage of the CSS 3 Grid Layout standard to avoid these problems when building Metro style applications using JavaScript. CSS 3 Grid Layout provides you with all of the benefits of using HTML tables for laying out a page without requiring you to use HTML table elements.

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  • Back from Russia

    - by Stephen Walther
    Thanks everyone who came to my talks on ASP.NET Web Forms and MVC in Moscow last week!  Here are the slide decks and demo code for the two talks (You need Visual Studio 2010):   What’s New in ASP.NET MVC 2?   What’s New in ASP.NET 4 Web Forms?   I had a great time in Russia. On the second day, I had an opportunity to walk around Moscow. Here’s a picture of me standing in Red Square:   Here’s a picture of me eating Chicken Kiev with Microsoft evangelist James Senior. James has just started his worldwide Web Camp tour to promote ASP.NET 4. He is traveling non-stop country to country. After Russia, he is off to China and Australia. You can find out more about the Web Camps here: http://www.webcamps.ms/

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  • How to remove the Bubble Notification of Empathy from the Notification Area

    - by Luis Alvarado
    There is a Bubble notification that appears in the notification area apart from the Mail Icon Message. I only want one notification icon telling me when a new message has arrived. Right now as seen in the image: I have the MAIL Icon (Which is White right now but turns blue when a new message arrives) and the First green icon, which is the bubbling talk icon that I want to remove. When a message appears both of them tell me a new message has arrives. I only want the MAIL icon (The white one between the Keyboard and the Bluetooth Icon)

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  • 10 Great Free Icon Packs To Theme Your Android Phone

    - by Chris Hoffman
    Android allows you to customize your home screen, adding widgets, arranging shortcuts and folders, choosing a background, and even replacing the included launcher entirely. You can install icon packs to theme your app icons, too. Third-party launchers use standard app icons by default, but they don’t have to. You can install icon packs that third-party launchers will use in place of standard app icons. How to Use Icon Packs To use icon packs, you’ll need to use a third-party launcher that supports them, such as Nova, Apex, ADW, Go Launcher, Holo Launcher, or Action Launcher Pro. Once you’re using a third-party launcher, you can install an icon pack and go into your launcher’s settings. You’ll find an option that allows you to choose between the icon packs you’ve installed. Many of these icon packs also include wallpapers, which you can set in the normal way. MIUI 5 Icons This icon pack offers over 1900 free icons that are similar to the icons used by the MIUi ROM developed by China’s Xiaomi Tech. The large list of icons is a big plus — this pack will give the majority of your app icons a very slick, consistent look. DCikonZ Theme DCikonZ is a free icon theme that includes a whopping 4000+ icons with a consistent look. This icon theme stands out not just because it’s huge, but also for offering for going in its own direction and avoiding the super-simple, flat look many icon packs use. Holo Icons Holo Icons replaces many app icons with simple, consistent-looking that match Google’s Holo style. If you’re a fan of Android’s Holo look, give it a try. It even tweaks many of the icons from Google’s own apps to make them look more consistent. Square Icon Pack Square Icon Pack turns your icons into simple squares. Even Google Chrome becomes an orb instead of a square. This makes every icon a consistent size and offers a unique look. The icons here almost look a bit like the small-size tiles available on Windows Phone and Windows 8.1. The free version doesn’t offer as many icons as the paid version, but it does offer icons for many popular apps. Rounded Want rounded icons instead? Try the Rounded icon theme, which offers simple rounded icons. The developer says they’re inspired by the consistently round icons used on Mozilla’s Firefox OS. Crumbled Icon Pack Crumbled Icon Pack applies an effect that makes icons look as if they’r crumbling. Rather than theming individual icons, Crumbled Icon Pack adds an effect to every app icon on your device. This means that all your app icons will be themed and consistent. Dainty Icon Pack Is your Android home screen too colorful? Dainty Icon Pack offers simple, gray-on-white icons for over 1200 apps. It’d be ideal over a simple background. The contrast may be a bit low here with the gray-on-white, but it’s otherwise very slick. Simplex Icons Simplex Icons offers more contrast, with black-on-gray icons. This icon pack could simplify busy home screens, allowing photographic wallpapers to come through. Min Icon Set Min attempts to go as minimal as possible, offering simple white icons for over 570 apps. It would be ideal over a simple wallpaper with app names hidden in your launcher, offering a calming, minimal home screen. For apps it doesn’t recognize, it will enclose part of the app’s icon in a white circle. Elegance Elegance goes in another direction entirely, offering icons that incorporate more details and gradients rather than going for minimalism. Its over 1200 icons offer another good option for people who aren’t into the minimal, flat look. Icon pack designers generally have to create and include their own icons to replace icons associated with specific apps, so you’ll probably find a few of your app icons aren’t replaced with most of these themes. Of course, a standard Android phone without an icon pack doesn’t have consistent icons, either. Even if all the icons in your app drawer aren’t themed, the few app icons you have on your home screen will be if you use widely used apps.     

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  • Metro: Promises

    - by Stephen.Walther
    The goal of this blog entry is to describe the Promise class in the WinJS library. You can use promises whenever you need to perform an asynchronous operation such as retrieving data from a remote website or a file from the file system. Promises are used extensively in the WinJS library. Asynchronous Programming Some code executes immediately, some code requires time to complete or might never complete at all. For example, retrieving the value of a local variable is an immediate operation. Retrieving data from a remote website takes longer or might not complete at all. When an operation might take a long time to complete, you should write your code so that it executes asynchronously. Instead of waiting for an operation to complete, you should start the operation and then do something else until you receive a signal that the operation is complete. An analogy. Some telephone customer service lines require you to wait on hold – listening to really bad music – until a customer service representative is available. This is synchronous programming and very wasteful of your time. Some newer customer service lines enable you to enter your telephone number so the customer service representative can call you back when a customer representative becomes available. This approach is much less wasteful of your time because you can do useful things while waiting for the callback. There are several patterns that you can use to write code which executes asynchronously. The most popular pattern in JavaScript is the callback pattern. When you call a function which might take a long time to return a result, you pass a callback function to the function. For example, the following code (which uses jQuery) includes a function named getFlickrPhotos which returns photos from the Flickr website which match a set of tags (such as “dog” and “funny”): function getFlickrPhotos(tags, callback) { $.getJSON( "http://api.flickr.com/services/feeds/photos_public.gne?jsoncallback=?", { tags: tags, tagmode: "all", format: "json" }, function (data) { if (callback) { callback(data.items); } } ); } getFlickrPhotos("funny, dogs", function(data) { $.each(data, function(index, item) { console.log(item); }); }); The getFlickr() function includes a callback parameter. When you call the getFlickr() function, you pass a function to the callback parameter which gets executed when the getFlicker() function finishes retrieving the list of photos from the Flickr web service. In the code above, the callback function simply iterates through the results and writes each result to the console. Using callbacks is a natural way to perform asynchronous programming with JavaScript. Instead of waiting for an operation to complete, sitting there and listening to really bad music, you can get a callback when the operation is complete. Using Promises The CommonJS website defines a promise like this (http://wiki.commonjs.org/wiki/Promises): “Promises provide a well-defined interface for interacting with an object that represents the result of an action that is performed asynchronously, and may or may not be finished at any given point in time. By utilizing a standard interface, different components can return promises for asynchronous actions and consumers can utilize the promises in a predictable manner.” A promise provides a standard pattern for specifying callbacks. In the WinJS library, when you create a promise, you can specify three callbacks: a complete callback, a failure callback, and a progress callback. Promises are used extensively in the WinJS library. The methods in the animation library, the control library, and the binding library all use promises. For example, the xhr() method included in the WinJS base library returns a promise. The xhr() method wraps calls to the standard XmlHttpRequest object in a promise. The following code illustrates how you can use the xhr() method to perform an Ajax request which retrieves a file named Photos.txt: var options = { url: "/data/photos.txt" }; WinJS.xhr(options).then( function (xmlHttpRequest) { console.log("success"); var data = JSON.parse(xmlHttpRequest.responseText); console.log(data); }, function(xmlHttpRequest) { console.log("fail"); }, function(xmlHttpRequest) { console.log("progress"); } ) The WinJS.xhr() method returns a promise. The Promise class includes a then() method which accepts three callback functions: a complete callback, an error callback, and a progress callback: Promise.then(completeCallback, errorCallback, progressCallback) In the code above, three anonymous functions are passed to the then() method. The three callbacks simply write a message to the JavaScript Console. The complete callback also dumps all of the data retrieved from the photos.txt file. Creating Promises You can create your own promises by creating a new instance of the Promise class. The constructor for the Promise class requires a function which accepts three parameters: a complete, error, and progress function parameter. For example, the code below illustrates how you can create a method named wait10Seconds() which returns a promise. The progress function is called every second and the complete function is not called until 10 seconds have passed: (function () { "use strict"; var app = WinJS.Application; function wait10Seconds() { return new WinJS.Promise(function (complete, error, progress) { var seconds = 0; var intervalId = window.setInterval(function () { seconds++; progress(seconds); if (seconds > 9) { window.clearInterval(intervalId); complete(); } }, 1000); }); } app.onactivated = function (eventObject) { if (eventObject.detail.kind === Windows.ApplicationModel.Activation.ActivationKind.launch) { wait10Seconds().then( function () { console.log("complete") }, function () { console.log("error") }, function (seconds) { console.log("progress:" + seconds) } ); } } app.start(); })(); All of the work happens in the constructor function for the promise. The window.setInterval() method is used to execute code every second. Every second, the progress() callback method is called. If more than 10 seconds have passed then the complete() callback method is called and the clearInterval() method is called. When you execute the code above, you can see the output in the Visual Studio JavaScript Console. Creating a Timeout Promise In the previous section, we created a custom Promise which uses the window.setInterval() method to complete the promise after 10 seconds. We really did not need to create a custom promise because the Promise class already includes a static method for returning promises which complete after a certain interval. The code below illustrates how you can use the timeout() method. The timeout() method returns a promise which completes after a certain number of milliseconds. WinJS.Promise.timeout(3000).then( function(){console.log("complete")}, function(){console.log("error")}, function(){console.log("progress")} ); In the code above, the Promise completes after 3 seconds (3000 milliseconds). The Promise returned by the timeout() method does not support progress events. Therefore, the only message written to the console is the message “complete” after 10 seconds. Canceling Promises Some promises, but not all, support cancellation. When you cancel a promise, the promise’s error callback is executed. For example, the following code uses the WinJS.xhr() method to perform an Ajax request. However, immediately after the Ajax request is made, the request is cancelled. // Specify Ajax request options var options = { url: "/data/photos.txt" }; // Make the Ajax request var request = WinJS.xhr(options).then( function (xmlHttpRequest) { console.log("success"); }, function (xmlHttpRequest) { console.log("fail"); }, function (xmlHttpRequest) { console.log("progress"); } ); // Cancel the Ajax request request.cancel(); When you run the code above, the message “fail” is written to the Visual Studio JavaScript Console. Composing Promises You can build promises out of other promises. In other words, you can compose promises. There are two static methods of the Promise class which you can use to compose promises: the join() method and the any() method. When you join promises, a promise is complete when all of the joined promises are complete. When you use the any() method, a promise is complete when any of the promises complete. The following code illustrates how to use the join() method. A new promise is created out of two timeout promises. The new promise does not complete until both of the timeout promises complete: WinJS.Promise.join([WinJS.Promise.timeout(1000), WinJS.Promise.timeout(5000)]) .then(function () { console.log("complete"); }); The message “complete” will not be written to the JavaScript Console until both promises passed to the join() method completes. The message won’t be written for 5 seconds (5,000 milliseconds). The any() method completes when any promise passed to the any() method completes: WinJS.Promise.any([WinJS.Promise.timeout(1000), WinJS.Promise.timeout(5000)]) .then(function () { console.log("complete"); }); The code above writes the message “complete” to the JavaScript Console after 1 second (1,000 milliseconds). The message is written to the JavaScript console immediately after the first promise completes and before the second promise completes. Summary The goal of this blog entry was to describe WinJS promises. First, we discussed how promises enable you to easily write code which performs asynchronous actions. You learned how to use a promise when performing an Ajax request. Next, we discussed how you can create your own promises. You learned how to create a new promise by creating a constructor function with complete, error, and progress parameters. Finally, you learned about several advanced methods of promises. You learned how to use the timeout() method to create promises which complete after an interval of time. You also learned how to cancel promises and compose promises from other promises.

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  • Metro: Using Templates

    - by Stephen.Walther
    The goal of this blog post is to describe how templates work in the WinJS library. In particular, you learn how to use a template to display both a single item and an array of items. You also learn how to load a template from an external file. Why use Templates? Imagine that you want to display a list of products in a page. The following code is bad: var products = [ { name: "Tesla", price: 80000 }, { name: "VW Rabbit", price: 200 }, { name: "BMW", price: 60000 } ]; var productsHTML = ""; for (var i = 0; i < products.length; i++) { productsHTML += "<h1>Product Details</h1>" + "<div>Product Name: " + products[i].name + "</div>" + "<div>Product Price: " + products[i].price + "</div>"; } document.getElementById("productContainer").innerHTML = productsHTML; In the code above, an array of products is displayed by creating a for..next loop which loops through each element in the array. A string which represents a list of products is built through concatenation. The code above is a designer’s nightmare. You cannot modify the appearance of the list of products without modifying the JavaScript code. A much better approach is to use a template like this: <div id="productTemplate"> <h1>Product Details</h1> <div> Product Name: <span data-win-bind="innerText:name"></span> </div> <div> Product Price: <span data-win-bind="innerText:price"></span> </div> </div> A template is simply a fragment of HTML that contains placeholders. Instead of displaying a list of products by concatenating together a string, you can render a template for each product. Creating a Simple Template Let’s start by using a template to render a single product. The following HTML page contains a template and a placeholder for rendering the template: <!DOCTYPE html> <html> <head> <meta charset="utf-8"> <title>Application1</title> <!-- WinJS references --> <link href="//Microsoft.WinJS.0.6/css/ui-dark.css" rel="stylesheet"> <script src="//Microsoft.WinJS.0.6/js/base.js"></script> <script src="//Microsoft.WinJS.0.6/js/ui.js"></script> <!-- Application1 references --> <link href="/css/default.css" rel="stylesheet"> <script src="/js/default.js"></script> </head> <body> <!-- Product Template --> <div id="productTemplate"> <h1>Product Details</h1> <div> Product Name: <span data-win-bind="innerText:name"></span> </div> <div> Product Price: <span data-win-bind="innerText:price"></span> </div> </div> <!-- Place where Product Template is Rendered --> <div id="productContainer"></div> </body> </html> In the page above, the template is defined in a DIV element with the id productTemplate. The contents of the productTemplate are not displayed when the page is opened in the browser. The contents of a template are automatically hidden when you convert the productTemplate into a template in your JavaScript code. Notice that the template uses data-win-bind attributes to display the product name and price properties. You can use both data-win-bind and data-win-bindsource attributes within a template. To learn more about these attributes, see my earlier blog post on WinJS data binding: http://stephenwalther.com/blog/archive/2012/02/26/windows-web-applications-declarative-data-binding.aspx The page above also includes a DIV element named productContainer. The rendered template is added to this element. Here’s the code for the default.js script which creates and renders the template: (function () { "use strict"; var app = WinJS.Application; app.onactivated = function (eventObject) { if (eventObject.detail.kind === Windows.ApplicationModel.Activation.ActivationKind.launch) { var product = { name: "Tesla", price: 80000 }; var productTemplate = new WinJS.Binding.Template(document.getElementById("productTemplate")); productTemplate.render(product, document.getElementById("productContainer")); } }; app.start(); })(); In the code above, a single product object is created with the following line of code: var product = { name: "Tesla", price: 80000 }; Next, the productTemplate element from the page is converted into an actual WinJS template with the following line of code: var productTemplate = new WinJS.Binding.Template(document.getElementById("productTemplate")); The template is rendered to the templateContainer element with the following line of code: productTemplate.render(product, document.getElementById("productContainer")); The result of this work is that the product details are displayed: Notice that you do not need to call WinJS.Binding.processAll(). The Template render() method takes care of the binding for you. Displaying an Array in a Template If you want to display an array of products using a template then you simply need to create a for..next loop and iterate through the array calling the Template render() method for each element. (function () { "use strict"; var app = WinJS.Application; app.onactivated = function (eventObject) { if (eventObject.detail.kind === Windows.ApplicationModel.Activation.ActivationKind.launch) { var products = [ { name: "Tesla", price: 80000 }, { name: "VW Rabbit", price: 200 }, { name: "BMW", price: 60000 } ]; var productTemplate = new WinJS.Binding.Template(document.getElementById("productTemplate")); var productContainer = document.getElementById("productContainer"); var i, product; for (i = 0; i < products.length; i++) { product = products[i]; productTemplate.render(product, productContainer); } } }; app.start(); })(); After each product in the array is rendered with the template, the result is appended to the productContainer element. No changes need to be made to the HTML page discussed in the previous section to display an array of products instead of a single product. The same product template can be used in both scenarios. Rendering an HTML TABLE with a Template When using the WinJS library, you create a template by creating an HTML element in your page. One drawback to this approach of creating templates is that your templates are part of your HTML page. In order for your HTML page to validate, the HTML within your templates must also validate. This means, for example, that you cannot enclose a single HTML table row within a template. The following HTML is invalid because you cannot place a TR element directly within the body of an HTML document:   <!-- Product Template --> <tr> <td data-win-bind="innerText:name"></td> <td data-win-bind="innerText:price"></td> </tr> This template won’t validate because, in a valid HTML5 document, a TR element must appear within a THEAD or TBODY element. Instead, you must create the entire TABLE element in the template. The following HTML page illustrates how you can create a template which contains a TR element: <!DOCTYPE html> <html> <head> <meta charset="utf-8"> <title>Application1</title> <!-- WinJS references --> <link href="//Microsoft.WinJS.0.6/css/ui-dark.css" rel="stylesheet"> <script src="//Microsoft.WinJS.0.6/js/base.js"></script> <script src="//Microsoft.WinJS.0.6/js/ui.js"></script> <!-- Application1 references --> <link href="/css/default.css" rel="stylesheet"> <script src="/js/default.js"></script> </head> <body> <!-- Product Template --> <div id="productTemplate"> <table> <tbody> <tr> <td data-win-bind="innerText:name"></td> <td data-win-bind="innerText:price"></td> </tr> </tbody> </table> </div> <!-- Place where Product Template is Rendered --> <table> <thead> <tr> <th>Name</th><th>Price</th> </tr> </thead> <tbody id="productContainer"> </tbody> </table> </body> </html>   In the HTML page above, the product template includes TABLE and TBODY elements: <!-- Product Template --> <div id="productTemplate"> <table> <tbody> <tr> <td data-win-bind="innerText:name"></td> <td data-win-bind="innerText:price"></td> </tr> </tbody> </table> </div> We discard these elements when we render the template. The only reason that we include the TABLE and THEAD elements in the template is to make the HTML page validate as valid HTML5 markup. Notice that the productContainer (the target of the template) in the page above is a TBODY element. We want to add the rows rendered by the template to the TBODY element in the page. The productTemplate is rendered in the default.js file: (function () { "use strict"; var app = WinJS.Application; app.onactivated = function (eventObject) { if (eventObject.detail.kind === Windows.ApplicationModel.Activation.ActivationKind.launch) { var products = [ { name: "Tesla", price: 80000 }, { name: "VW Rabbit", price: 200 }, { name: "BMW", price: 60000 } ]; var productTemplate = new WinJS.Binding.Template(document.getElementById("productTemplate")); var productContainer = document.getElementById("productContainer"); var i, product, row; for (i = 0; i < products.length; i++) { product = products[i]; productTemplate.render(product).then(function (result) { row = WinJS.Utilities.query("tr", result).get(0); productContainer.appendChild(row); }); } } }; app.start(); })(); When the product template is rendered, the TR element is extracted from the rendered template by using the WinJS.Utilities.query() method. Next, only the TR element is added to the productContainer: productTemplate.render(product).then(function (result) { row = WinJS.Utilities.query("tr", result).get(0); productContainer.appendChild(row); }); I discuss the WinJS.Utilities.query() method in depth in a previous blog entry: http://stephenwalther.com/blog/archive/2012/02/23/windows-web-applications-query-selectors.aspx When everything gets rendered, the products are displayed in an HTML table: You can see the actual HTML rendered by looking at the Visual Studio DOM Explorer window:   Loading an External Template Instead of embedding a template in an HTML page, you can place your template in an external HTML file. It makes sense to create a template in an external file when you need to use the same template in multiple pages. For example, you might need to use the same product template in multiple pages in your application. The following HTML page does not contain a template. It only contains a container that will act as a target for the rendered template: <!DOCTYPE html> <html> <head> <meta charset="utf-8"> <title>Application1</title> <!-- WinJS references --> <link href="//Microsoft.WinJS.0.6/css/ui-dark.css" rel="stylesheet"> <script src="//Microsoft.WinJS.0.6/js/base.js"></script> <script src="//Microsoft.WinJS.0.6/js/ui.js"></script> <!-- Application1 references --> <link href="/css/default.css" rel="stylesheet"> <script src="/js/default.js"></script> </head> <body> <!-- Place where Product Template is Rendered --> <div id="productContainer"></div> </body> </html> The template is contained in a separate file located at the path /templates/productTemplate.html:   Here’s the contents of the productTemplate.html file: <!-- Product Template --> <div id="productTemplate"> <h1>Product Details</h1> <div> Product Name: <span data-win-bind="innerText:name"></span> </div> <div> Product Price: <span data-win-bind="innerText:price"></span> </div> </div> Notice that the template file only contains the template and not the standard opening and closing HTML elements. It is an HTML fragment. If you prefer, you can include all of the standard opening and closing HTML elements in your external template – these elements get stripped away automatically: <html> <head><title>product template</title></head> <body> <!-- Product Template --> <div id="productTemplate"> <h1>Product Details</h1> <div> Product Name: <span data-win-bind="innerText:name"></span> </div> <div> Product Price: <span data-win-bind="innerText:price"></span> </div> </div> </body> </html> Either approach – using a fragment or using a full HTML document  — works fine. Finally, the following default.js file loads the external template, renders the template for each product, and appends the result to the product container: (function () { "use strict"; var app = WinJS.Application; app.onactivated = function (eventObject) { if (eventObject.detail.kind === Windows.ApplicationModel.Activation.ActivationKind.launch) { var products = [ { name: "Tesla", price: 80000 }, { name: "VW Rabbit", price: 200 }, { name: "BMW", price: 60000 } ]; var productTemplate = new WinJS.Binding.Template(null, { href: "/templates/productTemplate.html" }); var productContainer = document.getElementById("productContainer"); var i, product, row; for (i = 0; i < products.length; i++) { product = products[i]; productTemplate.render(product, productContainer); } } }; app.start(); })(); The path to the external template is passed to the constructor for the Template class as one of the options: var productTemplate = new WinJS.Binding.Template(null, {href:"/templates/productTemplate.html"}); When a template is contained in a page then you use the first parameter of the WinJS.Binding.Template constructor to represent the template – instead of null, you pass the element which contains the template. When a template is located in an external file, you pass the href for the file as part of the second parameter for the WinJS.Binding.Template constructor. Summary The goal of this blog entry was to describe how you can use WinJS templates to render either a single item or an array of items to a page. We also explored two advanced topics. You learned how to render an HTML table by extracting the TR element from a template. You also learned how to place a template in an external file.

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  • Metro Walkthrough: Creating a Task List with a ListView and IndexedDB

    - by Stephen.Walther
    The goal of this blog entry is to describe how you can work with data in a Metro style application written with JavaScript. In particular, we create a super simple Task List application which enables you to create and delete tasks. Here’s a video which demonstrates how the Task List application works: In order to build this application, I had to take advantage of several features of the WinJS library and technologies including: IndexedDB – The Task List application stores data in an IndexedDB database. HTML5 Form Validation – The Task List application uses HTML5 validation to ensure that a required field has a value. ListView Control – The Task List application displays the tasks retrieved from the IndexedDB database in a WinJS ListView control. Creating the IndexedDB Database The Task List application stores all of its data in an IndexedDB database named TasksDB. This database is opened/created with the following code: var db; var req = window.msIndexedDB.open("TasksDB", 1); req.onerror = function () { console.log("Could not open database"); }; req.onupgradeneeded = function (evt) { var newDB = evt.target.result; newDB.createObjectStore("tasks", { keyPath: "id", autoIncrement:true }); }; The msIndexedDB.open() method accepts two parameters: the name of the database to open and the version of the database to open. If a database with a matching version already exists, then calling the msIndexedDB.open() method opens a connection to the existing database. If the database does not exist then the upgradeneeded event is raised. You handle the upgradeneeded event to create a new database. In the code above, the upgradeneeded event handler creates an object store named “tasks” (An object store roughly corresponds to a database table). When you add items to the tasks object store then each item gets an id property with an auto-incremented value automatically. The code above also includes an error event handler. If the IndexedDB database cannot be opened or created, for whatever reason, then an error message is written to the Visual Studio JavaScript Console window. Displaying a List of Tasks The TaskList application retrieves its list of tasks from the tasks object store, which we created above, and displays the list of tasks in a ListView control. Here is how the ListView control is declared: <div id="tasksListView" data-win-control="WinJS.UI.ListView" data-win-options="{ itemDataSource: TaskList.tasks.dataSource, itemTemplate: select('#taskTemplate'), tapBehavior: 'toggleSelect', selectionMode: 'multi', layout: { type: WinJS.UI.ListLayout } }"> </div> The ListView control is bound to the TaskList.tasks.dataSource data source. The TaskList.tasks.dataSource is created with the following code: // Create the data source var tasks = new WinJS.Binding.List(); // Open the database var db; var req = window.msIndexedDB.open("TasksDB", 1); req.onerror = function () { console.log("Could not open database"); }; req.onupgradeneeded = function (evt) { var newDB = evt.target.result; newDB.createObjectStore("tasks", { keyPath: "id", autoIncrement:true }); }; // Load the data source with data from the database req.onsuccess = function () { db = req.result; var tran = db.transaction("tasks"); tran.objectStore("tasks").openCursor().onsuccess = function(event) { var cursor = event.target.result; if (cursor) { tasks.dataSource.insertAtEnd(null, cursor.value); cursor.continue(); }; }; }; // Expose the data source and functions WinJS.Namespace.define("TaskList", { tasks: tasks }); Notice the success event handler. This handler is called when a database is successfully opened/created. In the code above, all of the items from the tasks object store are retrieved into a cursor and added to a WinJS.Binding.List object named tasks. Because the ListView control is bound to the WinJS.Binding.List object, copying the tasks from the object store into the WinJS.Binding.List object causes the tasks to appear in the ListView: Adding a New Task You add a new task in the Task List application by entering the title of a new task into an HTML form and clicking the Add button. Here’s the markup for creating the form: <form id="addTaskForm"> <input id="newTaskTitle" title="New Task" required /> <button>Add</button> </form> Notice that the INPUT element includes a required attribute. In a Metro application, you can take advantage of HTML5 Validation to validate form fields. If you don’t enter a value for the newTaskTitle field then the following validation error message is displayed: For a brief introduction to HTML5 validation, see my previous blog entry: http://stephenwalther.com/blog/archive/2012/03/13/html5-form-validation.aspx When you click the Add button, the form is submitted and the form submit event is raised. The following code is executed in the default.js file: // Handle Add Task document.getElementById("addTaskForm").addEventListener("submit", function (evt) { evt.preventDefault(); var newTaskTitle = document.getElementById("newTaskTitle"); TaskList.addTask({ title: newTaskTitle.value }); newTaskTitle.value = ""; }); The code above retrieves the title of the new task and calls the addTask() method in the tasks.js file. Here’s the code for the addTask() method which is responsible for actually adding the new task to the IndexedDB database: // Add a new task function addTask(taskToAdd) { var transaction = db.transaction("tasks", "readwrite"); var addRequest = transaction.objectStore("tasks").add(taskToAdd); addRequest.onsuccess = function (evt) { taskToAdd.id = evt.target.result; tasks.dataSource.insertAtEnd(null, taskToAdd); } } The code above does two things. First, it adds the new task to the tasks object store in the IndexedDB database. Second, it adds the new task to the data source bound to the ListView. The dataSource.insertAtEnd() method is called to add the new task to the data source so the new task will appear in the ListView (with a nice little animation). Deleting Existing Tasks The Task List application enables you to select one or more tasks by clicking or tapping on one or more tasks in the ListView. When you click the Delete button, the selected tasks are removed from both the IndexedDB database and the ListView. For example, in the following screenshot, two tasks are selected. The selected tasks appear with a teal background and a checkmark: When you click the Delete button, the following code in the default.js file is executed: // Handle Delete Tasks document.getElementById("btnDeleteTasks").addEventListener("click", function (evt) { tasksListView.winControl.selection.getItems().then(function(items) { items.forEach(function (item) { TaskList.deleteTask(item); }); }); }); The selected tasks are retrieved with the TaskList selection.getItem() method. In the code above, the deleteTask() method is called for each of the selected tasks. Here’s the code for the deleteTask() method: // Delete an existing task function deleteTask(listViewItem) { // Database key != ListView key var dbKey = listViewItem.data.id; var listViewKey = listViewItem.key; // Remove item from db and, if success, remove item from ListView var transaction = db.transaction("tasks", “readwrite”); var deleteRequest = transaction.objectStore("tasks").delete(dbKey); deleteRequest.onsuccess = function () { tasks.dataSource.remove(listViewKey); } } This code does two things: it deletes the existing task from the database and removes the existing task from the ListView. In both cases, the right task is removed by using the key associated with the task. However, the task key is different in the case of the database and in the case of the ListView. In the case of the database, the task key is the value of the task id property. In the case of the ListView, on the other hand, the task key is auto-generated by the ListView. When the task is removed from the ListView, an animation is used to collapse the tasks which appear above and below the task which was removed. The Complete Code Above, I did a lot of jumping around between different files in the application and I left out sections of code. For the sake of completeness, I want to include the entire code here: the default.html, default.js, and tasks.js files. Here are the contents of the default.html file. This file contains the UI for the Task List application: <!DOCTYPE html> <html> <head> <meta charset="utf-8"> <title>Task List</title> <!-- WinJS references --> <link href="//Microsoft.WinJS.0.6/css/ui-dark.css" rel="stylesheet"> <script src="//Microsoft.WinJS.0.6/js/base.js"></script> <script src="//Microsoft.WinJS.0.6/js/ui.js"></script> <!-- TaskList references --> <link href="/css/default.css" rel="stylesheet"> <script src="/js/default.js"></script> <script type="text/javascript" src="js/tasks.js"></script> <style type="text/css"> body { font-size: x-large; } form { display: inline; } #appContainer { margin: 20px; width: 600px; } .win-container { padding: 10px; } </style> </head> <body> <div> <!-- Templates --> <div id="taskTemplate" data-win-control="WinJS.Binding.Template"> <div> <span data-win-bind="innerText:title"></span> </div> </div> <h1>Super Task List</h1> <div id="appContainer"> <form id="addTaskForm"> <input id="newTaskTitle" title="New Task" required /> <button>Add</button> </form> <button id="btnDeleteTasks">Delete</button> <div id="tasksListView" data-win-control="WinJS.UI.ListView" data-win-options="{ itemDataSource: TaskList.tasks.dataSource, itemTemplate: select('#taskTemplate'), tapBehavior: 'toggleSelect', selectionMode: 'multi', layout: { type: WinJS.UI.ListLayout } }"> </div> </div> </div> </body> </html> Here is the code for the default.js file. This code wires up the Add Task form and Delete button: (function () { "use strict"; var app = WinJS.Application; app.onactivated = function (eventObject) { if (eventObject.detail.kind === Windows.ApplicationModel.Activation.ActivationKind.launch) { WinJS.UI.processAll().then(function () { // Get reference to Tasks ListView var tasksListView = document.getElementById("tasksListView"); // Handle Add Task document.getElementById("addTaskForm").addEventListener("submit", function (evt) { evt.preventDefault(); var newTaskTitle = document.getElementById("newTaskTitle"); TaskList.addTask({ title: newTaskTitle.value }); newTaskTitle.value = ""; }); // Handle Delete Tasks document.getElementById("btnDeleteTasks").addEventListener("click", function (evt) { tasksListView.winControl.selection.getItems().then(function(items) { items.forEach(function (item) { TaskList.deleteTask(item); }); }); }); }); } }; app.start(); })(); Finally, here is the tasks.js file. This file contains all of the code for opening, creating, and interacting with IndexedDB: (function () { "use strict"; // Create the data source var tasks = new WinJS.Binding.List(); // Open the database var db; var req = window.msIndexedDB.open("TasksDB", 1); req.onerror = function () { console.log("Could not open database"); }; req.onupgradeneeded = function (evt) { var newDB = evt.target.result; newDB.createObjectStore("tasks", { keyPath: "id", autoIncrement:true }); }; // Load the data source with data from the database req.onsuccess = function () { db = req.result; var tran = db.transaction("tasks"); tran.objectStore("tasks").openCursor().onsuccess = function(event) { var cursor = event.target.result; if (cursor) { tasks.dataSource.insertAtEnd(null, cursor.value); cursor.continue(); }; }; }; // Add a new task function addTask(taskToAdd) { var transaction = db.transaction("tasks", "readwrite"); var addRequest = transaction.objectStore("tasks").add(taskToAdd); addRequest.onsuccess = function (evt) { taskToAdd.id = evt.target.result; tasks.dataSource.insertAtEnd(null, taskToAdd); } } // Delete an existing task function deleteTask(listViewItem) { // Database key != ListView key var dbKey = listViewItem.data.id; var listViewKey = listViewItem.key; // Remove item from db and, if success, remove item from ListView var transaction = db.transaction("tasks", "readwrite"); var deleteRequest = transaction.objectStore("tasks").delete(dbKey); deleteRequest.onsuccess = function () { tasks.dataSource.remove(listViewKey); } } // Expose the data source and functions WinJS.Namespace.define("TaskList", { tasks: tasks, addTask: addTask, deleteTask: deleteTask }); })(); Summary I wrote this blog entry because I wanted to create a walkthrough of building a simple database-driven application. In particular, I wanted to demonstrate how you can use a ListView control with an IndexedDB database to store and retrieve database data.

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  • Metro: Namespaces and Modules

    - by Stephen.Walther
    The goal of this blog entry is to describe how you can use the Windows JavaScript (WinJS) library to create namespaces. In particular, you learn how to use the WinJS.Namespace.define() and WinJS.Namespace.defineWithParent() methods. You also learn how to hide private methods by using the module pattern. Why Do We Need Namespaces? Before we do anything else, we should start by answering the question: Why do we need namespaces? What function do they serve? Do they just add needless complexity to our Metro applications? After all, plenty of JavaScript libraries do just fine without introducing support for namespaces. For example, jQuery has no support for namespaces and jQuery is the most popular JavaScript library in the universe. If jQuery can do without namespaces, why do we need to worry about namespaces at all? Namespaces perform two functions in a programming language. First, namespaces prevent naming collisions. In other words, namespaces enable you to create more than one object with the same name without conflict. For example, imagine that two companies – company A and company B – both want to make a JavaScript shopping cart control and both companies want to name the control ShoppingCart. By creating a CompanyA namespace and CompanyB namespace, both companies can create a ShoppingCart control: a CompanyA.ShoppingCart and a CompanyB.ShoppingCart control. The second function of a namespace is organization. Namespaces are used to group related functionality even when the functionality is defined in different physical files. For example, I know that all of the methods in the WinJS library related to working with classes can be found in the WinJS.Class namespace. Namespaces make it easier to understand the functionality available in a library. If you are building a simple JavaScript application then you won’t have much reason to care about namespaces. If you need to use multiple libraries written by different people then namespaces become very important. Using WinJS.Namespace.define() In the WinJS library, the most basic method of creating a namespace is to use the WinJS.Namespace.define() method. This method enables you to declare a namespace (of arbitrary depth). The WinJS.Namespace.define() method has the following parameters: · name – A string representing the name of the new namespace. You can add nested namespace by using dot notation · members – An optional collection of objects to add to the new namespace For example, the following code sample declares two new namespaces named CompanyA and CompanyB.Controls. Both namespaces contain a ShoppingCart object which has a checkout() method: // Create CompanyA namespace with ShoppingCart WinJS.Namespace.define("CompanyA"); CompanyA.ShoppingCart = { checkout: function (){ return "Checking out from A"; } }; // Create CompanyB.Controls namespace with ShoppingCart WinJS.Namespace.define( "CompanyB.Controls", { ShoppingCart: { checkout: function(){ return "Checking out from B"; } } } ); // Call CompanyA ShoppingCart checkout method console.log(CompanyA.ShoppingCart.checkout()); // Writes "Checking out from A" // Call CompanyB.Controls checkout method console.log(CompanyB.Controls.ShoppingCart.checkout()); // Writes "Checking out from B" In the code above, the CompanyA namespace is created by calling WinJS.Namespace.define(“CompanyA”). Next, the ShoppingCart is added to this namespace. The namespace is defined and an object is added to the namespace in separate lines of code. A different approach is taken in the case of the CompanyB.Controls namespace. The namespace is created and the ShoppingCart object is added to the namespace with the following single line of code: WinJS.Namespace.define( "CompanyB.Controls", { ShoppingCart: { checkout: function(){ return "Checking out from B"; } } } ); Notice that CompanyB.Controls is a nested namespace. The top level namespace CompanyB contains the namespace Controls. You can declare a nested namespace using dot notation and the WinJS library handles the details of creating one namespace within the other. After the namespaces have been defined, you can use either of the two shopping cart controls. You call CompanyA.ShoppingCart.checkout() or you can call CompanyB.Controls.ShoppingCart.checkout(). Using WinJS.Namespace.defineWithParent() The WinJS.Namespace.defineWithParent() method is similar to the WinJS.Namespace.define() method. Both methods enable you to define a new namespace. The difference is that the defineWithParent() method enables you to add a new namespace to an existing namespace. The WinJS.Namespace.defineWithParent() method has the following parameters: · parentNamespace – An object which represents a parent namespace · name – A string representing the new namespace to add to the parent namespace · members – An optional collection of objects to add to the new namespace The following code sample demonstrates how you can create a root namespace named CompanyA and add a Controls child namespace to the CompanyA parent namespace: WinJS.Namespace.define("CompanyA"); WinJS.Namespace.defineWithParent(CompanyA, "Controls", { ShoppingCart: { checkout: function () { return "Checking out"; } } } ); console.log(CompanyA.Controls.ShoppingCart.checkout()); // Writes "Checking out" One significant advantage of using the defineWithParent() method over the define() method is the defineWithParent() method is strongly-typed. In other words, you use an object to represent the base namespace instead of a string. If you misspell the name of the object (CompnyA) then you get a runtime error. Using the Module Pattern When you are building a JavaScript library, you want to be able to create both public and private methods. Some methods, the public methods, are intended to be used by consumers of your JavaScript library. The public methods act as your library’s public API. Other methods, the private methods, are not intended for public consumption. Instead, these methods are internal methods required to get the library to function. You don’t want people calling these internal methods because you might need to change them in the future. JavaScript does not support access modifiers. You can’t mark an object or method as public or private. Anyone gets to call any method and anyone gets to interact with any object. The only mechanism for encapsulating (hiding) methods and objects in JavaScript is to take advantage of functions. In JavaScript, a function determines variable scope. A JavaScript variable either has global scope – it is available everywhere – or it has function scope – it is available only within a function. If you want to hide an object or method then you need to place it within a function. For example, the following code contains a function named doSomething() which contains a nested function named doSomethingElse(): function doSomething() { console.log("doSomething"); function doSomethingElse() { console.log("doSomethingElse"); } } doSomething(); // Writes "doSomething" doSomethingElse(); // Throws ReferenceError You can call doSomethingElse() only within the doSomething() function. The doSomethingElse() function is encapsulated in the doSomething() function. The WinJS library takes advantage of function encapsulation to hide all of its internal methods. All of the WinJS methods are defined within self-executing anonymous functions. Everything is hidden by default. Public methods are exposed by explicitly adding the public methods to namespaces defined in the global scope. Imagine, for example, that I want a small library of utility methods. I want to create a method for calculating sales tax and a method for calculating the expected ship date of a product. The following library encapsulates the implementation of my library in a self-executing anonymous function: (function (global) { // Public method which calculates tax function calculateTax(price) { return calculateFederalTax(price) + calculateStateTax(price); } // Private method for calculating state tax function calculateStateTax(price) { return price * 0.08; } // Private method for calculating federal tax function calculateFederalTax(price) { return price * 0.02; } // Public method which returns the expected ship date function calculateShipDate(currentDate) { currentDate.setDate(currentDate.getDate() + 4); return currentDate; } // Export public methods WinJS.Namespace.define("CompanyA.Utilities", { calculateTax: calculateTax, calculateShipDate: calculateShipDate } ); })(this); // Show expected ship date var shipDate = CompanyA.Utilities.calculateShipDate(new Date()); console.log(shipDate); // Show price + tax var price = 12.33; var tax = CompanyA.Utilities.calculateTax(price); console.log(price + tax); In the code above, the self-executing anonymous function contains four functions: calculateTax(), calculateStateTax(), calculateFederalTax(), and calculateShipDate(). The following statement is used to expose only the calcuateTax() and the calculateShipDate() functions: // Export public methods WinJS.Namespace.define("CompanyA.Utilities", { calculateTax: calculateTax, calculateShipDate: calculateShipDate } ); Because the calculateTax() and calcuateShipDate() functions are added to the CompanyA.Utilities namespace, you can call these two methods outside of the self-executing function. These are the public methods of your library which form the public API. The calculateStateTax() and calculateFederalTax() methods, on the other hand, are forever hidden within the black hole of the self-executing function. These methods are encapsulated and can never be called outside of scope of the self-executing function. These are the internal methods of your library. Summary The goal of this blog entry was to describe why and how you use namespaces with the WinJS library. You learned how to define namespaces using both the WinJS.Namespace.define() and WinJS.Namespace.defineWithParent() methods. We also discussed how to hide private members and expose public members using the module pattern.

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  • Ajax Talk at .NET Developers Association

    - by Stephen Walther
    Thanks everyone who came to my Ajax talk tonight at the .NET Developers Association! The slides and demos from the talk can be downloaded by clicking the following link:   ASP.NET Ajax: What’s New?    You need Visual Studio  2010 to view the code samples. The first project, named Demos, contains the following samples: ASPAjax4 1_CompositeScripts.aspx – Demonstrates how to use the ScriptManger to combine, compress, and cache JavaScript files automatically. 2_EnableCdn.aspx – Demonstrates how to retrieve ASP.NET Ajax framework scripts from the Microsoft Ajax CDN automatically. jQuery 1_Selectors.aspx – Demonstrates how to use jQuery selectors 2_WebForms.aspx – Demonstrates how to use the client tablesorter plugin with ASP.NET Web Forms. 3_MVC.aspx – Demonstrates how to use jQuery animation and the templating plugin with ASP.NET MVC. 4_OData.aspx – Demonstrates how to use jQuery with the Netflix API by using JSONP and odata. 5_Templating.aspx – Demonstrates how to use jQuery client templating. 6_TemplateConditionals.aspx – Demonstrates how to use logic within a jQuery template. 7_DataLinking.aspx – Demonstrates how to perform data-binding in jQuery. 8_Converters.aspx – Demonstrates how to defines converters that work with data-binding. The second project, named ACT_Tools, illustrates how to use the Microsoft Ajax Minifier and the JSBuild JavaScript preprocessor. When you perform a build in Visual Studio, all JavaScript and CSS files are minified automatically. Furthermore, any *.pre.js file is processed using the JSBuild preprocessor and the output is saved to the ScriptOutput folder. Select Show All Files in Visual Studio to see the generated results of the minifier and the preprocessor.

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  • Speaking at Tech-Ed Europe Next Week

    - by Stephen Walther
    I’m going to Berlin! Next week, I’m giving talks at Tech-Ed Europe on two of my favorite topics: What's New in Microsoft ASP.NET Model-View-Controller ASP.NET Model-View-Controller (MVC) 2 introduces new features to make you more productive when building an ASP.NET MVC application. Templated helpers allow automatically associatiating edit and display elements with data types. Areas provide a means of dividing a large Web application into multiple projects. Data annotations allow attaching metadata attributes on a model to control validation. Microsoft ASP.NET AJAX: Taking AJAX to the Next Level Hear how ASP.NET AJAX 4.0 makes building pure client-side AJAX Web applications even easier, and watch us build an entire data-driven ASP.NET AJAX application from start to finish by taking advantage of only JavaScript, HTML pages, and Windows Communication Foundation (WCF) services. Also learn about new ASP.NET AJAX features including the DataView control, declarative templates, live client-side data binding, WCF, and REST integration.   The conference has sold out, but you can register for the wait list: http://www.microsoft.com/europe/TechEd/

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  • Good Book for Learning Meteor: Discover Meteor

    - by Stephen.Walther
    A week or so ago, Sacha Greif asked me whether I would be willing to write a review of his new book on Meteor (published today) entitled Discover Meteor. Sacha wrote the book with Tom Coleman. Both Sacha and Tom are very active in the Meteor community – they are responsible for several well-known Meteor packages and projects including Atmosphere, Meteorite, meteor-router and Telescope — so I suspected that their book would be good. If you have not heard of Meteor, Meteor is a new framework for building web applications which is built on top of Node.js. Meteor excels at building a new category of constantly-connected, real-time web applications. It has some jaw-dropping features which I described in a previous blog entry: http://stephenwalther.com/archive/2013/03/18/an-introduction-to-meteor.aspx So, I am super excited about Meteor. Unfortunately, because it is evolving so quickly, learning how to write Meteor applications can be challenging. The official documentation at Meteor.com is good, but it is too basic. I’m happy to report that Discovering Meteor is a really good book: · The book is a fun read. The writing is smooth and I read through the book from cover to cover in a single Saturday afternoon with pleasure. · The book is well organized. It contains a walk-through of building a social media app (Microscope). Interleaved through the app building chapters, it contains tutorial chapters on Meteor features such as deployment and reactivity. · The book covers several advanced topics which I have not seen covered anywhere else. The chapters on publications and subscriptions, routing, and animation are especially good. I came away from the book with a deeper understanding of all of these topics. I wish that I had read Discover Meteor a couple of months ago and it would have saved me several weeks of reading Stack Overflow posts and struggling with the Meteor documentation If you want to buy Discover Meteor, the authors gave me the following link which provides you with a 20% discount: http://discovermeteor.com/orionids

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  • Metro: Creating a Master/Detail View with a WinJS ListView Control

    - by Stephen.Walther
    The goal of this blog entry is to explain how you can create a simple master/detail view by using the WinJS ListView and Template controls. In particular, I explain how you can use a ListView control to display a list of movies and how you can use a Template control to display the details of the selected movie. Creating a master/detail view requires completing the following four steps: Create the data source – The data source contains the list of movies. Declare the ListView control – The ListView control displays the entire list of movies. It is the master part of the master/detail view. Declare the Details Template control – The Details Template control displays the details for the selected movie. It is the details part of the master/detail view. Handle the selectionchanged event – You handle the selectionchanged event to display the details for a movie when a new movie is selected. Creating the Data Source There is nothing special about our data source. We initialize a WinJS.Binding.List object to represent a list of movies: (function () { "use strict"; var movies = new WinJS.Binding.List([ { title: "Star Wars", director: "Lucas"}, { title: "Shrek", director: "Adamson" }, { title: "Star Trek", director: "Abrams" }, { title: "Spiderman", director: "Raimi" }, { title: "Memento", director: "Nolan" }, { title: "Minority Report", director: "Spielberg" } ]); // Expose the data source WinJS.Namespace.define("ListViewDemos", { movies: movies }); })(); The data source is exposed to the rest of our application with the name ListViewDemos.movies. Declaring the ListView Control The ListView control is declared with the following markup: <div id="movieList" data-win-control="WinJS.UI.ListView" data-win-options="{ itemDataSource: ListViewDemos.movies.dataSource, itemTemplate: select('#masterItemTemplate'), tapBehavior: 'directSelect', selectionMode: 'single', layout: { type: WinJS.UI.ListLayout } }"> </div> The data-win-options attribute is used to set the following properties of the ListView control: itemDataSource – The ListView is bound to the list of movies which we created in the previous section. Notice that the ListView is bound to ListViewDemos.movies.dataSource and not just ListViewDemos.movies. itemTemplate – The item template contains the template used for rendering each item in the ListView. The markup for this template is included below. tabBehavior – This enumeration determines what happens when you tap or click on an item in the ListView. The possible values are directSelect, toggleSelect, invokeOnly, none. Because we want to handle the selectionchanged event, we set tapBehavior to the value directSelect. selectionMode – This enumeration determines whether you can select multiple items or only a single item. The possible values are none, single, multi. In the code above, this property is set to the value single. layout – You can use ListLayout or GridLayout with a ListView. If you want to display a vertical ListView, then you should select ListLayout. You must associate a ListView with an item template if you want to render anything interesting. The ListView above is associated with an item template named #masterItemTemplate. Here’s the markup for the masterItemTemplate: <div id="masterItemTemplate" data-win-control="WinJS.Binding.Template"> <div class="movie"> <span data-win-bind="innerText:title"></span> </div> </div> This template simply renders the title of each movie. Declaring the Details Template Control The details part of the master/detail view is created with the help of a Template control. Here’s the markup used to declare the Details Template control: <div id="detailsTemplate" data-win-control="WinJS.Binding.Template"> <div> <div> Title: <span data-win-bind="innerText:title"></span> </div> <div> Director: <span data-win-bind="innerText:director"></span> </div> </div> </div> The Details Template control displays the movie title and director.   Handling the selectionchanged Event The ListView control can raise two types of events: the iteminvoked and selectionchanged events. The iteminvoked event is raised when you click on a ListView item. The selectionchanged event is raised when one or more ListView items are selected. When you set the tapBehavior property of the ListView control to the value “directSelect” then tapping or clicking a list item raised both the iteminvoked and selectionchanged event. Tapping a list item causes the item to be selected and the item appears with a checkmark. In our code, we handle the selectionchanged event to update the movie details Template when you select a new movie. Here’s the code from the default.js file used to handle the selectionchanged event: var movieList = document.getElementById("movieList"); var detailsTemplate = document.getElementById("detailsTemplate"); var movieDetails = document.getElementById("movieDetails"); // Setup selectionchanged handler movieList.winControl.addEventListener("selectionchanged", function (evt) { if (movieList.winControl.selection.count() > 0) { movieList.winControl.selection.getItems().then(function (items) { // Clear the template container movieDetails.innerHTML = ""; // Render the template detailsTemplate.winControl.render(items[0].data, movieDetails); }); } }); The code above sets up an event handler (listener) for the selectionchanged event. The event handler first verifies that an item has been selected in the ListView (selection.count() > 0). Next, the details for the movie are rendered using the movie details Template (we created this Template in the previous section). The Complete Code For the sake of completeness, I’ve included the complete code for the master/detail view below. I’ve included both the default.html, default.js, and movies.js files. Here is the final code for the default.html file: <!DOCTYPE html> <html> <head> <meta charset="utf-8"> <title>ListViewMasterDetail</title> <!-- WinJS references --> <link href="//Microsoft.WinJS.0.6/css/ui-dark.css" rel="stylesheet"> <script src="//Microsoft.WinJS.0.6/js/base.js"></script> <script src="//Microsoft.WinJS.0.6/js/ui.js"></script> <!-- ListViewMasterDetail references --> <link href="/css/default.css" rel="stylesheet"> <script src="/js/default.js"></script> <script type="text/javascript" src="js/movies.js"></script> <style type="text/css"> body { font-size: xx-large; } .movie { padding: 5px; } #masterDetail { display: -ms-box; } #movieList { width: 300px; margin: 20px; } #movieDetails { margin: 20px; } </style> </head> <body> <!-- Templates --> <div id="masterItemTemplate" data-win-control="WinJS.Binding.Template"> <div class="movie"> <span data-win-bind="innerText:title"></span> </div> </div> <div id="detailsTemplate" data-win-control="WinJS.Binding.Template"> <div> <div> Title: <span data-win-bind="innerText:title"></span> </div> <div> Director: <span data-win-bind="innerText:director"></span> </div> </div> </div> <!-- Master/Detail --> <div id="masterDetail"> <!-- Master --> <div id="movieList" data-win-control="WinJS.UI.ListView" data-win-options="{ itemDataSource: ListViewDemos.movies.dataSource, itemTemplate: select('#masterItemTemplate'), tapBehavior: 'directSelect', selectionMode: 'single', layout: { type: WinJS.UI.ListLayout } }"> </div> <!-- Detail --> <div id="movieDetails"></div> </div> </body> </html> Here is the default.js file: (function () { "use strict"; var app = WinJS.Application; app.onactivated = function (eventObject) { if (eventObject.detail.kind === Windows.ApplicationModel.Activation.ActivationKind.launch) { WinJS.UI.processAll(); var movieList = document.getElementById("movieList"); var detailsTemplate = document.getElementById("detailsTemplate"); var movieDetails = document.getElementById("movieDetails"); // Setup selectionchanged handler movieList.winControl.addEventListener("selectionchanged", function (evt) { if (movieList.winControl.selection.count() > 0) { movieList.winControl.selection.getItems().then(function (items) { // Clear the template container movieDetails.innerHTML = ""; // Render the template detailsTemplate.winControl.render(items[0].data, movieDetails); }); } }); } }; app.start(); })();   Here is the movies.js file: (function () { "use strict"; var movies = new WinJS.Binding.List([ { title: "Star Wars", director: "Lucas"}, { title: "Shrek", director: "Adamson" }, { title: "Star Trek", director: "Abrams" }, { title: "Spiderman", director: "Raimi" }, { title: "Memento", director: "Nolan" }, { title: "Minority Report", director: "Spielberg" } ]); // Expose the data source WinJS.Namespace.define("ListViewDemos", { movies: movies }); })();   Summary The purpose of this blog entry was to describe how to create a simple master/detail view by taking advantage of the WinJS ListView control. We handled the selectionchanged event of the ListView control to display movie details when you select a movie in the ListView.

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  • Time Tracking on an Agile Team

    - by Stephen.Walther
    What’s the best way to handle time-tracking on an Agile team? Your gut reaction to this question might be to resist any type of time-tracking at all. After all, one of the principles of the Agile Manifesto is “Individuals and interactions over processes and tools”.  Forcing the developers on your team to track the amount of time that they devote to completing stories or tasks might seem like useless bureaucratic red tape: an impediment to getting real work done. I completely understand this reaction. I’ve been required to use time-tracking software in the past to account for each hour of my workday. It made me feel like Fred Flintstone punching in at the quarry mine and not like a professional. Why You Really Do Need Time-Tracking There are, however, legitimate reasons to track time spent on stories even when you are a member of an Agile team.  First, if you are working with an outside client, you might need to track the number of hours spent on different stories for the purposes of billing. There might be no way to avoid time-tracking if you want to get paid. Second, the Product Owner needs to know when the work on a story has gone over the original time estimated for the story. The Product Owner is concerned with Return On Investment. If the team has gone massively overtime on a story, then the Product Owner has a legitimate reason to halt work on the story and reconsider the story’s business value. Finally, you might want to track how much time your team spends on different types of stories or tasks. For example, if your team is spending 75% of their time doing testing then you might need to bring in more testers. Or, if 10% of your team’s time is expended performing a software build at the end of each iteration then it is time to consider better ways of automating the build process. Time-Tracking in SonicAgile For these reasons, we added time-tracking as a feature to SonicAgile which is our free Agile Project Management tool. We were heavily influenced by Jeff Sutherland (one of the founders of Scrum) in the way that we implemented time-tracking (see his article http://scrum.jeffsutherland.com/2007/03/time-tracking-is-anti-scrum-what-do-you.html). In SonicAgile, time-tracking is disabled by default. If you want to use this feature then the project owner must enable time-tracking in Project Settings. You can choose to estimate using either days or hours. If you are estimating at the level of stories then it makes more sense to choose days. Otherwise, if you are estimating at the level of tasks then it makes more sense to use hours. After you enable time-tracking then you can assign three estimates to a story: Original Estimate – This is the estimate that you enter when you first create a story. You don’t change this estimate. Time Spent – This is the amount of time that you have already devoted to the story. You update the time spent on each story during your daily standup meeting. Time Left – This is the amount of time remaining to complete the story. Again, you update the time left during your daily standup meeting. So when you first create a story, you enter an original estimate that becomes the time left. During each daily standup meeting, you update the time spent and time left for each story on the Kanban. If you had perfect predicative power, then the original estimate would always be the same as the sum of the time spent and the time left. For example, if you predict that a story will take 5 days to complete then on day 3, the story should have 3 days spent and 2 days left. Unfortunately, never in the history of mankind has anyone accurately predicted the exact amount of time that it takes to complete a story. For this reason, SonicAgile does not update the time spent and time left automatically. Each day, during the daily standup, your team should update the time spent and time left for each story. For example, the following table shows the history of the time estimates for a story that was originally estimated to take 3 days but, eventually, takes 5 days to complete: Day Original Estimate Time Spent Time Left Day 1 3 days 0 days 3 days Day 2 3 days 1 day 2 days Day 3 3 days 2 days 2 days Day 4 3 days 3 days 2 days Day 5 3 days 4 days 0 days In the table above, everything goes as predicted until you reach day 3. On day 3, the team realizes that the work will require an additional two days. The situation does not improve on day 4. All of the sudden, on day 5, all of the remaining work gets done. Real work often follows this pattern. There are long periods when nothing gets done punctuated by occasional and unpredictable bursts of progress. We designed SonicAgile to make it as easy as possible to track the time spent and time left on a story. Detecting when a Story Goes Over the Original Estimate Sometimes, stories take much longer than originally estimated. There’s a surprise. For example, you discover that a new software component is incompatible with existing software components. Or, you discover that you have to go through a month-long certification process to finish a story. In those cases, the Product Owner has a legitimate reason to halt work on a story and re-evaluate the business value of the story. For example, the Product Owner discovers that a story will require weeks to implement instead of days, then the story might not be worth the expense. SonicAgile displays a warning on both the Backlog and the Kanban when the time spent on a story goes over the original estimate. An icon of a clock is displayed. Time-Tracking and Tasks Another optional feature of SonicAgile is tasks. If you enable Tasks in Project Settings then you can break stories into one or more tasks. You can perform time-tracking at the level of a story or at the level of a task. If you don’t break a story into tasks then you can enter the time left and time spent for the story. As soon as you break a story into tasks, then you can no longer enter the time left and time spent at the level of the story. Instead, the time left and time spent for a story is rolled up from its tasks. On the Kanban, you can see how the time left and time spent for each task gets rolled up into each story. The progress bar for the story is rolled up from the progress bars for each task. The original estimate is never rolled up – even when you break a story into tasks. A story’s original estimate is entered separately from the original estimates of each of the story’s tasks. Summary Not every Agile team can avoid time-tracking. You might be forced to track time to get paid, to detect when you are spending too much time on a particular story, or to track the amount of time that you are devoting to different types of tasks. We designed time-tracking in SonicAgile to require the least amount of work to track the information that you need. Time-tracking is an optional feature. If you enable time-tracking then you can track the original estimate, time left, and time spent for each story and task. You can use time-tracking with SonicAgile for free. Register at http://SonicAgile.com.

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  • Metro: Creating an IndexedDbDataSource for WinJS

    - by Stephen.Walther
    The goal of this blog entry is to describe how you can create custom data sources which you can use with the controls in the WinJS library. In particular, I explain how you can create an IndexedDbDataSource which you can use to store and retrieve data from an IndexedDB database. If you want to skip ahead, and ignore all of the fascinating content in-between, I’ve included the complete code for the IndexedDbDataSource at the very bottom of this blog entry. What is IndexedDB? IndexedDB is a database in the browser. You can use the IndexedDB API with all modern browsers including Firefox, Chrome, and Internet Explorer 10. And, of course, you can use IndexedDB with Metro style apps written with JavaScript. If you need to persist data in a Metro style app written with JavaScript then IndexedDB is a good option. Each Metro app can only interact with its own IndexedDB databases. And, IndexedDB provides you with transactions, indices, and cursors – the elements of any modern database. An IndexedDB database might be different than the type of database that you normally use. An IndexedDB database is an object-oriented database and not a relational database. Instead of storing data in tables, you store data in object stores. You store JavaScript objects in an IndexedDB object store. You create new IndexedDB object stores by handling the upgradeneeded event when you attempt to open a connection to an IndexedDB database. For example, here’s how you would both open a connection to an existing database named TasksDB and create the TasksDB database when it does not already exist: var reqOpen = window.indexedDB.open(“TasksDB”, 2); reqOpen.onupgradeneeded = function (evt) { var newDB = evt.target.result; newDB.createObjectStore("tasks", { keyPath: "id", autoIncrement: true }); }; reqOpen.onsuccess = function () { var db = reqOpen.result; // Do something with db }; When you call window.indexedDB.open(), and the database does not already exist, then the upgradeneeded event is raised. In the code above, the upgradeneeded handler creates a new object store named tasks. The new object store has an auto-increment column named id which acts as the primary key column. If the database already exists with the right version, and you call window.indexedDB.open(), then the success event is raised. At that point, you have an open connection to the existing database and you can start doing something with the database. You use asynchronous methods to interact with an IndexedDB database. For example, the following code illustrates how you would add a new object to the tasks object store: var transaction = db.transaction(“tasks”, “readwrite”); var reqAdd = transaction.objectStore(“tasks”).add({ name: “Feed the dog” }); reqAdd.onsuccess = function() { // Tasks added successfully }; The code above creates a new database transaction, adds a new task to the tasks object store, and handles the success event. If the new task gets added successfully then the success event is raised. Creating a WinJS IndexedDbDataSource The most powerful control in the WinJS library is the ListView control. This is the control that you use to display a collection of items. If you want to display data with a ListView control, you need to bind the control to a data source. The WinJS library includes two objects which you can use as a data source: the List object and the StorageDataSource object. The List object enables you to represent a JavaScript array as a data source and the StorageDataSource enables you to represent the file system as a data source. If you want to bind an IndexedDB database to a ListView then you have a choice. You can either dump the items from the IndexedDB database into a List object or you can create a custom data source. I explored the first approach in a previous blog entry. In this blog entry, I explain how you can create a custom IndexedDB data source. Implementing the IListDataSource Interface You create a custom data source by implementing the IListDataSource interface. This interface contains the contract for the methods which the ListView needs to interact with a data source. The easiest way to implement the IListDataSource interface is to derive a new object from the base VirtualizedDataSource object. The VirtualizedDataSource object requires a data adapter which implements the IListDataAdapter interface. Yes, because of the number of objects involved, this is a little confusing. Your code ends up looking something like this: var IndexedDbDataSource = WinJS.Class.derive( WinJS.UI.VirtualizedDataSource, function (dbName, dbVersion, objectStoreName, upgrade, error) { this._adapter = new IndexedDbDataAdapter(dbName, dbVersion, objectStoreName, upgrade, error); this._baseDataSourceConstructor(this._adapter); }, { nuke: function () { this._adapter.nuke(); }, remove: function (key) { this._adapter.removeInternal(key); } } ); The code above is used to create a new class named IndexedDbDataSource which derives from the base VirtualizedDataSource class. In the constructor for the new class, the base class _baseDataSourceConstructor() method is called. A data adapter is passed to the _baseDataSourceConstructor() method. The code above creates a new method exposed by the IndexedDbDataSource named nuke(). The nuke() method deletes all of the objects from an object store. The code above also overrides a method named remove(). Our derived remove() method accepts any type of key and removes the matching item from the object store. Almost all of the work of creating a custom data source goes into building the data adapter class. The data adapter class implements the IListDataAdapter interface which contains the following methods: · change() · getCount() · insertAfter() · insertAtEnd() · insertAtStart() · insertBefore() · itemsFromDescription() · itemsFromEnd() · itemsFromIndex() · itemsFromKey() · itemsFromStart() · itemSignature() · moveAfter() · moveBefore() · moveToEnd() · moveToStart() · remove() · setNotificationHandler() · compareByIdentity Fortunately, you are not required to implement all of these methods. You only need to implement the methods that you actually need. In the case of the IndexedDbDataSource, I implemented the getCount(), itemsFromIndex(), insertAtEnd(), and remove() methods. If you are creating a read-only data source then you really only need to implement the getCount() and itemsFromIndex() methods. Implementing the getCount() Method The getCount() method returns the total number of items from the data source. So, if you are storing 10,000 items in an object store then this method would return the value 10,000. Here’s how I implemented the getCount() method: getCount: function () { var that = this; return new WinJS.Promise(function (complete, error) { that._getObjectStore().then(function (store) { var reqCount = store.count(); reqCount.onerror = that._error; reqCount.onsuccess = function (evt) { complete(evt.target.result); }; }); }); } The first thing that you should notice is that the getCount() method returns a WinJS promise. This is a requirement. The getCount() method is asynchronous which is a good thing because all of the IndexedDB methods (at least the methods implemented in current browsers) are also asynchronous. The code above retrieves an object store and then uses the IndexedDB count() method to get a count of the items in the object store. The value is returned from the promise by calling complete(). Implementing the itemsFromIndex method When a ListView displays its items, it calls the itemsFromIndex() method. By default, it calls this method multiple times to get different ranges of items. Three parameters are passed to the itemsFromIndex() method: the requestIndex, countBefore, and countAfter parameters. The requestIndex indicates the index of the item from the database to show. The countBefore and countAfter parameters represent hints. These are integer values which represent the number of items before and after the requestIndex to retrieve. Again, these are only hints and you can return as many items before and after the request index as you please. Here’s how I implemented the itemsFromIndex method: itemsFromIndex: function (requestIndex, countBefore, countAfter) { var that = this; return new WinJS.Promise(function (complete, error) { that.getCount().then(function (count) { if (requestIndex >= count) { return WinJS.Promise.wrapError(new WinJS.ErrorFromName(WinJS.UI.FetchError.doesNotExist)); } var startIndex = Math.max(0, requestIndex - countBefore); var endIndex = Math.min(count, requestIndex + countAfter + 1); that._getObjectStore().then(function (store) { var index = 0; var items = []; var req = store.openCursor(); req.onerror = that._error; req.onsuccess = function (evt) { var cursor = evt.target.result; if (index < startIndex) { index = startIndex; cursor.advance(startIndex); return; } if (cursor && index < endIndex) { index++; items.push({ key: cursor.value[store.keyPath].toString(), data: cursor.value }); cursor.continue(); return; } results = { items: items, offset: requestIndex - startIndex, totalCount: count }; complete(results); }; }); }); }); } In the code above, a cursor is used to iterate through the objects in an object store. You fetch the next item in the cursor by calling either the cursor.continue() or cursor.advance() method. The continue() method moves forward by one object and the advance() method moves forward a specified number of objects. Each time you call continue() or advance(), the success event is raised again. If the cursor is null then you know that you have reached the end of the cursor and you can return the results. Some things to be careful about here. First, the return value from the itemsFromIndex() method must implement the IFetchResult interface. In particular, you must return an object which has an items, offset, and totalCount property. Second, each item in the items array must implement the IListItem interface. Each item should have a key and a data property. Implementing the insertAtEnd() Method When creating the IndexedDbDataSource, I wanted to go beyond creating a simple read-only data source and support inserting and deleting objects. If you want to support adding new items with your data source then you need to implement the insertAtEnd() method. Here’s how I implemented the insertAtEnd() method for the IndexedDbDataSource: insertAtEnd:function(unused, data) { var that = this; return new WinJS.Promise(function (complete, error) { that._getObjectStore("readwrite").done(function(store) { var reqAdd = store.add(data); reqAdd.onerror = that._error; reqAdd.onsuccess = function (evt) { var reqGet = store.get(evt.target.result); reqGet.onerror = that._error; reqGet.onsuccess = function (evt) { var newItem = { key:evt.target.result[store.keyPath].toString(), data:evt.target.result } complete(newItem); }; }; }); }); } When implementing the insertAtEnd() method, you need to be careful to return an object which implements the IItem interface. In particular, you should return an object that has a key and a data property. The key must be a string and it uniquely represents the new item added to the data source. The value of the data property represents the new item itself. Implementing the remove() Method Finally, you use the remove() method to remove an item from the data source. You call the remove() method with the key of the item which you want to remove. Implementing the remove() method in the case of the IndexedDbDataSource was a little tricky. The problem is that an IndexedDB object store uses an integer key and the VirtualizedDataSource requires a string key. For that reason, I needed to override the remove() method in the derived IndexedDbDataSource class like this: var IndexedDbDataSource = WinJS.Class.derive( WinJS.UI.VirtualizedDataSource, function (dbName, dbVersion, objectStoreName, upgrade, error) { this._adapter = new IndexedDbDataAdapter(dbName, dbVersion, objectStoreName, upgrade, error); this._baseDataSourceConstructor(this._adapter); }, { nuke: function () { this._adapter.nuke(); }, remove: function (key) { this._adapter.removeInternal(key); } } ); When you call remove(), you end up calling a method of the IndexedDbDataAdapter named removeInternal() . Here’s what the removeInternal() method looks like: setNotificationHandler: function (notificationHandler) { this._notificationHandler = notificationHandler; }, removeInternal: function(key) { var that = this; return new WinJS.Promise(function (complete, error) { that._getObjectStore("readwrite").done(function (store) { var reqDelete = store.delete (key); reqDelete.onerror = that._error; reqDelete.onsuccess = function (evt) { that._notificationHandler.removed(key.toString()); complete(); }; }); }); } The removeInternal() method calls the IndexedDB delete() method to delete an item from the object store. If the item is deleted successfully then the _notificationHandler.remove() method is called. Because we are not implementing the standard IListDataAdapter remove() method, we need to notify the data source (and the ListView control bound to the data source) that an item has been removed. The way that you notify the data source is by calling the _notificationHandler.remove() method. Notice that we get the _notificationHandler in the code above by implementing another method in the IListDataAdapter interface: the setNotificationHandler() method. You can raise the following types of notifications using the _notificationHandler: · beginNotifications() · changed() · endNotifications() · inserted() · invalidateAll() · moved() · removed() · reload() These methods are all part of the IListDataNotificationHandler interface in the WinJS library. Implementing the nuke() Method I wanted to implement a method which would remove all of the items from an object store. Therefore, I created a method named nuke() which calls the IndexedDB clear() method: nuke: function () { var that = this; return new WinJS.Promise(function (complete, error) { that._getObjectStore("readwrite").done(function (store) { var reqClear = store.clear(); reqClear.onerror = that._error; reqClear.onsuccess = function (evt) { that._notificationHandler.reload(); complete(); }; }); }); } Notice that the nuke() method calls the _notificationHandler.reload() method to notify the ListView to reload all of the items from its data source. Because we are implementing a custom method here, we need to use the _notificationHandler to send an update. Using the IndexedDbDataSource To illustrate how you can use the IndexedDbDataSource, I created a simple task list app. You can add new tasks, delete existing tasks, and nuke all of the tasks. You delete an item by selecting an item (swipe or right-click) and clicking the Delete button. Here’s the HTML page which contains the ListView, the form for adding new tasks, and the buttons for deleting and nuking tasks: <!DOCTYPE html> <html> <head> <meta charset="utf-8" /> <title>DataSources</title> <!-- WinJS references --> <link href="//Microsoft.WinJS.1.0.RC/css/ui-dark.css" rel="stylesheet" /> <script src="//Microsoft.WinJS.1.0.RC/js/base.js"></script> <script src="//Microsoft.WinJS.1.0.RC/js/ui.js"></script> <!-- DataSources references --> <link href="indexedDb.css" rel="stylesheet" /> <script type="text/javascript" src="indexedDbDataSource.js"></script> <script src="indexedDb.js"></script> </head> <body> <div id="tmplTask" data-win-control="WinJS.Binding.Template"> <div class="taskItem"> Id: <span data-win-bind="innerText:id"></span> <br /><br /> Name: <span data-win-bind="innerText:name"></span> </div> </div> <div id="lvTasks" data-win-control="WinJS.UI.ListView" data-win-options="{ itemTemplate: select('#tmplTask'), selectionMode: 'single' }"></div> <form id="frmAdd"> <fieldset> <legend>Add Task</legend> <label>New Task</label> <input id="inputTaskName" required /> <button>Add</button> </fieldset> </form> <button id="btnNuke">Nuke</button> <button id="btnDelete">Delete</button> </body> </html> And here is the JavaScript code for the TaskList app: /// <reference path="//Microsoft.WinJS.1.0.RC/js/base.js" /> /// <reference path="//Microsoft.WinJS.1.0.RC/js/ui.js" /> function init() { WinJS.UI.processAll().done(function () { var lvTasks = document.getElementById("lvTasks").winControl; // Bind the ListView to its data source var tasksDataSource = new DataSources.IndexedDbDataSource("TasksDB", 1, "tasks", upgrade); lvTasks.itemDataSource = tasksDataSource; // Wire-up Add, Delete, Nuke buttons document.getElementById("frmAdd").addEventListener("submit", function (evt) { evt.preventDefault(); tasksDataSource.beginEdits(); tasksDataSource.insertAtEnd(null, { name: document.getElementById("inputTaskName").value }).done(function (newItem) { tasksDataSource.endEdits(); document.getElementById("frmAdd").reset(); lvTasks.ensureVisible(newItem.index); }); }); document.getElementById("btnDelete").addEventListener("click", function () { if (lvTasks.selection.count() == 1) { lvTasks.selection.getItems().done(function (items) { tasksDataSource.remove(items[0].data.id); }); } }); document.getElementById("btnNuke").addEventListener("click", function () { tasksDataSource.nuke(); }); // This method is called to initialize the IndexedDb database function upgrade(evt) { var newDB = evt.target.result; newDB.createObjectStore("tasks", { keyPath: "id", autoIncrement: true }); } }); } document.addEventListener("DOMContentLoaded", init); The IndexedDbDataSource is created and bound to the ListView control with the following two lines of code: var tasksDataSource = new DataSources.IndexedDbDataSource("TasksDB", 1, "tasks", upgrade); lvTasks.itemDataSource = tasksDataSource; The IndexedDbDataSource is created with four parameters: the name of the database to create, the version of the database to create, the name of the object store to create, and a function which contains code to initialize the new database. The upgrade function creates a new object store named tasks with an auto-increment property named id: function upgrade(evt) { var newDB = evt.target.result; newDB.createObjectStore("tasks", { keyPath: "id", autoIncrement: true }); } The Complete Code for the IndexedDbDataSource Here’s the complete code for the IndexedDbDataSource: (function () { /************************************************ * The IndexedDBDataAdapter enables you to work * with a HTML5 IndexedDB database. *************************************************/ var IndexedDbDataAdapter = WinJS.Class.define( function (dbName, dbVersion, objectStoreName, upgrade, error) { this._dbName = dbName; // database name this._dbVersion = dbVersion; // database version this._objectStoreName = objectStoreName; // object store name this._upgrade = upgrade; // database upgrade script this._error = error || function (evt) { console.log(evt.message); }; }, { /******************************************* * IListDataAdapter Interface Methods ********************************************/ getCount: function () { var that = this; return new WinJS.Promise(function (complete, error) { that._getObjectStore().then(function (store) { var reqCount = store.count(); reqCount.onerror = that._error; reqCount.onsuccess = function (evt) { complete(evt.target.result); }; }); }); }, itemsFromIndex: function (requestIndex, countBefore, countAfter) { var that = this; return new WinJS.Promise(function (complete, error) { that.getCount().then(function (count) { if (requestIndex >= count) { return WinJS.Promise.wrapError(new WinJS.ErrorFromName(WinJS.UI.FetchError.doesNotExist)); } var startIndex = Math.max(0, requestIndex - countBefore); var endIndex = Math.min(count, requestIndex + countAfter + 1); that._getObjectStore().then(function (store) { var index = 0; var items = []; var req = store.openCursor(); req.onerror = that._error; req.onsuccess = function (evt) { var cursor = evt.target.result; if (index < startIndex) { index = startIndex; cursor.advance(startIndex); return; } if (cursor && index < endIndex) { index++; items.push({ key: cursor.value[store.keyPath].toString(), data: cursor.value }); cursor.continue(); return; } results = { items: items, offset: requestIndex - startIndex, totalCount: count }; complete(results); }; }); }); }); }, insertAtEnd:function(unused, data) { var that = this; return new WinJS.Promise(function (complete, error) { that._getObjectStore("readwrite").done(function(store) { var reqAdd = store.add(data); reqAdd.onerror = that._error; reqAdd.onsuccess = function (evt) { var reqGet = store.get(evt.target.result); reqGet.onerror = that._error; reqGet.onsuccess = function (evt) { var newItem = { key:evt.target.result[store.keyPath].toString(), data:evt.target.result } complete(newItem); }; }; }); }); }, setNotificationHandler: function (notificationHandler) { this._notificationHandler = notificationHandler; }, /***************************************** * IndexedDbDataSource Method ******************************************/ removeInternal: function(key) { var that = this; return new WinJS.Promise(function (complete, error) { that._getObjectStore("readwrite").done(function (store) { var reqDelete = store.delete (key); reqDelete.onerror = that._error; reqDelete.onsuccess = function (evt) { that._notificationHandler.removed(key.toString()); complete(); }; }); }); }, nuke: function () { var that = this; return new WinJS.Promise(function (complete, error) { that._getObjectStore("readwrite").done(function (store) { var reqClear = store.clear(); reqClear.onerror = that._error; reqClear.onsuccess = function (evt) { that._notificationHandler.reload(); complete(); }; }); }); }, /******************************************* * Private Methods ********************************************/ _ensureDbOpen: function () { var that = this; // Try to get cached Db if (that._cachedDb) { return WinJS.Promise.wrap(that._cachedDb); } // Otherwise, open the database return new WinJS.Promise(function (complete, error, progress) { var reqOpen = window.indexedDB.open(that._dbName, that._dbVersion); reqOpen.onerror = function (evt) { error(); }; reqOpen.onupgradeneeded = function (evt) { that._upgrade(evt); that._notificationHandler.invalidateAll(); }; reqOpen.onsuccess = function () { that._cachedDb = reqOpen.result; complete(that._cachedDb); }; }); }, _getObjectStore: function (type) { type = type || "readonly"; var that = this; return new WinJS.Promise(function (complete, error) { that._ensureDbOpen().then(function (db) { var transaction = db.transaction(that._objectStoreName, type); complete(transaction.objectStore(that._objectStoreName)); }); }); }, _get: function (key) { return new WinJS.Promise(function (complete, error) { that._getObjectStore().done(function (store) { var reqGet = store.get(key); reqGet.onerror = that._error; reqGet.onsuccess = function (item) { complete(item); }; }); }); } } ); var IndexedDbDataSource = WinJS.Class.derive( WinJS.UI.VirtualizedDataSource, function (dbName, dbVersion, objectStoreName, upgrade, error) { this._adapter = new IndexedDbDataAdapter(dbName, dbVersion, objectStoreName, upgrade, error); this._baseDataSourceConstructor(this._adapter); }, { nuke: function () { this._adapter.nuke(); }, remove: function (key) { this._adapter.removeInternal(key); } } ); WinJS.Namespace.define("DataSources", { IndexedDbDataSource: IndexedDbDataSource }); })(); Summary In this blog post, I provided an overview of how you can create a new data source which you can use with the WinJS library. I described how you can create an IndexedDbDataSource which you can use to bind a ListView control to an IndexedDB database. While describing how you can create a custom data source, I explained how you can implement the IListDataAdapter interface. You also learned how to raise notifications — such as a removed or invalidateAll notification — by taking advantage of the methods of the IListDataNotificationHandler interface.

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  • Metro: Understanding Observables

    - by Stephen.Walther
    The goal of this blog entry is to describe how the Observer Pattern is implemented in the WinJS library. You learn how to create observable objects which trigger notifications automatically when their properties are changed. Observables enable you to keep your user interface and your application data in sync. For example, by taking advantage of observables, you can update your user interface automatically whenever the properties of a product change. Observables are the foundation of declarative binding in the WinJS library. The WinJS library is not the first JavaScript library to include support for observables. For example, both the KnockoutJS library and the Microsoft Ajax Library (now part of the Ajax Control Toolkit) support observables. Creating an Observable Imagine that I have created a product object like this: var product = { name: "Milk", description: "Something to drink", price: 12.33 }; Nothing very exciting about this product. It has three properties named name, description, and price. Now, imagine that I want to be notified automatically whenever any of these properties are changed. In that case, I can create an observable product from my product object like this: var observableProduct = WinJS.Binding.as(product); This line of code creates a new JavaScript object named observableProduct from the existing JavaScript object named product. This new object also has a name, description, and price property. However, unlike the properties of the original product object, the properties of the observable product object trigger notifications when the properties are changed. Each of the properties of the new observable product object has been changed into accessor properties which have both a getter and a setter. For example, the observable product price property looks something like this: price: { get: function () { return this.getProperty(“price”); } set: function (value) { this.setProperty(“price”, value); } } When you read the price property then the getProperty() method is called and when you set the price property then the setProperty() method is called. The getProperty() and setProperty() methods are methods of the observable product object. The observable product object supports the following methods and properties: · addProperty(name, value) – Adds a new property to an observable and notifies any listeners. · backingData – An object which represents the value of each property. · bind(name, action) – Enables you to execute a function when a property changes. · getProperty(name) – Returns the value of a property using the string name of the property. · notify(name, newValue, oldValue) – A private method which executes each function in the _listeners array. · removeProperty(name) – Removes a property and notifies any listeners. · setProperty(name, value) – Updates a property and notifies any listeners. · unbind(name, action) – Enables you to stop executing a function in response to a property change. · updateProperty(name, value) – Updates a property and notifies any listeners. So when you create an observable, you get a new object with the same properties as an existing object. However, when you modify the properties of an observable object, then you can notify any listeners of the observable that the value of a particular property has changed automatically. Imagine that you change the value of the price property like this: observableProduct.price = 2.99; In that case, the following sequence of events is triggered: 1. The price setter calls the setProperty(“price”, 2.99) method 2. The setProperty() method updates the value of the backingData.price property and calls the notify() method 3. The notify() method executes each function in the collection of listeners associated with the price property Creating Observable Listeners If you want to be notified when a property of an observable object is changed, then you need to register a listener. You register a listener by using the bind() method like this: (function () { "use strict"; var app = WinJS.Application; app.onactivated = function (eventObject) { if (eventObject.detail.kind === Windows.ApplicationModel.Activation.ActivationKind.launch) { // Simple product object var product = { name: "Milk", description: "Something to drink", price: 12.33 }; // Create observable product var observableProduct = WinJS.Binding.as(product); // Execute a function when price is changed observableProduct.bind("price", function (newValue) { console.log(newValue); }); // Change the price observableProduct.price = 2.99; } }; app.start(); })(); In the code above, the bind() method is used to associate the price property with a function. When the price property is changed, the function logs the new value of the price property to the Visual Studio JavaScript console. The price property is associated with the function using the following line of code: // Execute a function when price is changed observableProduct.bind("price", function (newValue) { console.log(newValue); }); Coalescing Notifications If you make multiple changes to a property – one change immediately following another – then separate notifications won’t be sent. Instead, any listeners are notified only once. The notifications are coalesced into a single notification. For example, in the following code, the product price property is updated three times. However, only one message is written to the JavaScript console. Only the last value assigned to the price property is written to the JavaScript Console window: // Simple product object var product = { name: "Milk", description: "Something to drink", price: 12.33 }; // Create observable product var observableProduct = WinJS.Binding.as(product); // Execute a function when price is changed observableProduct.bind("price", function (newValue) { console.log(newValue); }); // Change the price observableProduct.price = 3.99; observableProduct.price = 2.99; observableProduct.price = 1.99; Only the last value assigned to price, the value 1.99, appears in the console: If there is a time delay between changes to a property then changes result in different notifications. For example, the following code updates the price property every second: // Simple product object var product = { name: "Milk", description: "Something to drink", price: 12.33 }; // Create observable product var observableProduct = WinJS.Binding.as(product); // Execute a function when price is changed observableProduct.bind("price", function (newValue) { console.log(newValue); }); // Add 1 to price every second window.setInterval(function () { observableProduct.price += 1; }, 1000); In this case, separate notification messages are logged to the JavaScript Console window: If you need to prevent multiple notifications from being coalesced into one then you can take advantage of promises. I discussed WinJS promises in a previous blog entry: http://stephenwalther.com/blog/archive/2012/02/22/windows-web-applications-promises.aspx Because the updateProperty() method returns a promise, you can create different notifications for each change in a property by using the following code: // Change the price observableProduct.updateProperty("price", 3.99) .then(function () { observableProduct.updateProperty("price", 2.99) .then(function () { observableProduct.updateProperty("price", 1.99); }); }); In this case, even though the price is immediately changed from 3.99 to 2.99 to 1.99, separate notifications for each new value of the price property are sent. Bypassing Notifications Normally, if a property of an observable object has listeners and you change the property then the listeners are notified. However, there are certain situations in which you might want to bypass notification. In other words, you might need to change a property value silently without triggering any functions registered for notification. If you want to change a property without triggering notifications then you should change the property by using the backingData property. The following code illustrates how you can change the price property silently: // Simple product object var product = { name: "Milk", description: "Something to drink", price: 12.33 }; // Create observable product var observableProduct = WinJS.Binding.as(product); // Execute a function when price is changed observableProduct.bind("price", function (newValue) { console.log(newValue); }); // Change the price silently observableProduct.backingData.price = 5.99; console.log(observableProduct.price); // Writes 5.99 The price is changed to the value 5.99 by changing the value of backingData.price. Because the observableProduct.price property is not set directly, any listeners associated with the price property are not notified. When you change the value of a property by using the backingData property, the change in the property happens synchronously. However, when you change the value of an observable property directly, the change is always made asynchronously. Summary The goal of this blog entry was to describe observables. In particular, we discussed how to create observables from existing JavaScript objects and bind functions to observable properties. You also learned how notifications are coalesced (and ways to prevent this coalescing). Finally, we discussed how you can use the backingData property to update an observable property without triggering notifications. In the next blog entry, we’ll see how observables are used with declarative binding to display the values of properties in an HTML document.

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  • New January 2013 Release of the Ajax Control Toolkit

    - by Stephen.Walther
    I am super excited to announce the January 2013 release of the Ajax Control Toolkit! I have one word to describe this release and that word is “Charts” – we’ve added lots of great new chart controls to the Ajax Control Toolkit. You can download the new release directly from http://AjaxControlToolkit.CodePlex.com – or, just fire the following command from the Visual Studio Library Package Manager Console Window (NuGet): Install-Package AjaxControlToolkit You also can view the new chart controls by visiting the “live” Ajax Control Toolkit Sample Site. 5 New Ajax Control Toolkit Chart Controls The Ajax Control Toolkit contains five new chart controls: the AreaChart, BarChart, BubbleChart, LineChart, and PieChart controls. Here is a sample of each of the controls: AreaChart: BarChart: BubbleChart: LineChart: PieChart: We realize that people love to customize the appearance of their charts so all of the chart controls include properties such as color properties. The chart controls render the chart on the browser using SVG. The chart controls are compatible with any browser which supports SVG including Internet Explorer 9 and new and recent versions of Google Chrome, Mozilla Firefox, and Apple Safari. (If you attempt to display a chart on a browser which does not support SVG then you won’t get an error – you just won’t get anything). Updates to the HTML Sanitizer If you are using the HtmlEditorExtender on a public-facing website then it is really important that you enable the HTML Sanitizer to prevent Cross-Site Scripting (XSS) attacks. The HtmlEditorExtender uses the HTML Sanitizer by default. The HTML Sanitizer strips out any suspicious content (like JavaScript code and CSS expressions) from the HTML submitted with the HtmlEditorExtender. We followed the recommendations of OWASP and ha.ckers.org to identify suspicious content. We updated the HTML Sanitizer with this release to protect against new types of XSS attacks. The HTML Sanitizer now has over 220 unit tests. The Ajax Control Toolkit team would like to thank Gil Cohen who helped us identify and block additional XSS attacks. Change in Ajax Control Toolkit Version Format We ran out of numbers. The Ajax Control Toolkit was first released way back in 2006. In previous releases, the version of the Ajax Control Toolkit followed the format: Release Year + Date. So, the previous release was 60919 where 6 represented the 6th release year and 0919 represent September 19. Unfortunately, the AssembyVersion attribute uses a UInt16 data type which has a maximum size of 65,534. The number 70123 is bigger than 65,534 so we had to change our version format with this release. Fortunately, the AssemblyVersion attribute actually accepts four UInt16 numbers so we used another one. This release of the Ajax Control Toolkit is officially version 7.0123. This new version format should work for another 65,000 years. And yes, I realize that 7.0123 is less than 60,919, but we ran out of numbers. Summary I hope that you find the chart controls included with this latest release of the Ajax Control Toolkit useful. Let me know if you use them in applications that you build. And, let me know if you run into any issues using the new chart controls. Next month, back to improving the File Upload control – more exciting stuff.

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  • Metro: Understanding the default.js File

    - by Stephen.Walther
    The goal of this blog entry is to describe — in painful detail — the contents of the default.js file in a Metro style application written with JavaScript. When you use Visual Studio to create a new Metro application then you get a default.js file automatically. The file is located in a folder named \js\default.js. The default.js file kicks off all of your custom JavaScript code. It is the main entry point to a Metro application. The default contents of the default.js file are included below: // For an introduction to the Blank template, see the following documentation: // http://go.microsoft.com/fwlink/?LinkId=232509 (function () { "use strict"; var app = WinJS.Application; app.onactivated = function (eventObject) { if (eventObject.detail.kind === Windows.ApplicationModel.Activation.ActivationKind.launch) { if (eventObject.detail.previousExecutionState !== Windows.ApplicationModel.Activation.ApplicationExecutionState.terminated) { // TODO: This application has been newly launched. Initialize // your application here. } else { // TODO: This application has been reactivated from suspension. // Restore application state here. } WinJS.UI.processAll(); } }; app.oncheckpoint = function (eventObject) { // TODO: This application is about to be suspended. Save any state // that needs to persist across suspensions here. You might use the // WinJS.Application.sessionState object, which is automatically // saved and restored across suspension. If you need to complete an // asynchronous operation before your application is suspended, call // eventObject.setPromise(). }; app.start(); })(); There are several mysterious things happening in this file. The purpose of this blog entry is to dispel this mystery. Understanding the Module Pattern The first thing that you should notice about the default.js file is that the entire contents of this file are enclosed within a self-executing JavaScript function: (function () { ... })(); Metro applications written with JavaScript use something called the module pattern. The module pattern is a common pattern used in JavaScript applications to create private variables, objects, and methods. Anything that you create within the module is encapsulated within the module. Enclosing all of your custom code within a module prevents you from stomping on code from other libraries accidently. Your application might reference several JavaScript libraries and the JavaScript libraries might have variables, objects, or methods with the same names. By encapsulating your code in a module, you avoid overwriting variables, objects, or methods in the other libraries accidently. Enabling Strict Mode with “use strict” The first statement within the default.js module enables JavaScript strict mode: 'use strict'; Strict mode is a new feature of ECMAScript 5 (the latest standard for JavaScript) which enables you to make JavaScript more strict. For example, when strict mode is enabled, you cannot declare variables without using the var keyword. The following statement would result in an exception: hello = "world!"; When strict mode is enabled, this statement throws a ReferenceError. When strict mode is not enabled, a global variable is created which, most likely, is not what you want to happen. I’d rather get the exception instead of the unwanted global variable. The full specification for strict mode is contained in the ECMAScript 5 specification (look at Annex C): http://www.ecma-international.org/publications/files/ECMA-ST/ECMA-262.pdf Aliasing the WinJS.Application Object The next line of code in the default.js file is used to alias the WinJS.Application object: var app = WinJS.Application; This line of code enables you to use a short-hand syntax when referring to the WinJS.Application object: for example,  app.onactivated instead of WinJS.Application.onactivated. The WinJS.Application object  represents your running Metro application. Handling Application Events The default.js file contains an event handler for the WinJS.Application activated event: app.onactivated = function (eventObject) { if (eventObject.detail.kind === Windows.ApplicationModel.Activation.ActivationKind.launch) { if (eventObject.detail.previousExecutionState !== Windows.ApplicationModel.Activation.ApplicationExecutionState.terminated) { // TODO: This application has been newly launched. Initialize // your application here. } else { // TODO: This application has been reactivated from suspension. // Restore application state here. } WinJS.UI.processAll(); } }; This WinJS.Application class supports the following events: · loaded – Happens after browser DOMContentLoaded event. After this event, the DOM is ready and you can access elements in a page. This event is raised before external images have been loaded. · activated – Triggered by the Windows.UI.WebUI.WebUIApplication activated event. After this event, the WinRT is ready. · ready – Happens after both loaded and activated events. · unloaded – Happens before application is unloaded. The following default.js file has been modified to capture each of these events and write a message to the Visual Studio JavaScript Console window: (function () { "use strict"; var app = WinJS.Application; WinJS.Application.onloaded = function (e) { console.log("Loaded"); }; WinJS.Application.onactivated = function (e) { console.log("Activated"); }; WinJS.Application.onready = function (e) { console.log("Ready"); } WinJS.Application.onunload = function (e) { console.log("Unload"); } app.start(); })(); When you execute the code above, a message is written to the Visual Studio JavaScript Console window when each event occurs with the exception of the Unload event (presumably because the console is not attached when that event is raised).   Handling Different Activation Contexts The code for the activated handler in the default.js file looks like this: app.onactivated = function (eventObject) { if (eventObject.detail.kind === Windows.ApplicationModel.Activation.ActivationKind.launch) { if (eventObject.detail.previousExecutionState !== Windows.ApplicationModel.Activation.ApplicationExecutionState.terminated) { // TODO: This application has been newly launched. Initialize // your application here. } else { // TODO: This application has been reactivated from suspension. // Restore application state here. } WinJS.UI.processAll(); } }; Notice that the code contains a conditional which checks the Kind of the event (the value of e.detail.kind). The startup code is executed only when the activated event is triggered by a Launch event, The ActivationKind enumeration has the following values: · launch · search · shareTarget · file · protocol · fileOpenPicker · fileSavePicker · cacheFileUpdater · contactPicker · device · printTaskSettings · cameraSettings Metro style applications can be activated in different contexts. For example, a camera application can be activated when modifying camera settings. In that case, the ActivationKind would be CameraSettings. Because we want to execute our JavaScript code when our application first launches, we verify that the kind of the activation event is an ActivationKind.Launch event. There is a second conditional within the activated event handler which checks whether an application is being newly launched or whether the application is being resumed from a suspended state. When running a Metro application with Visual Studio, you can use Visual Studio to simulate different application execution states by taking advantage of the Debug toolbar and the new Debug Location toolbar.  Handling the checkpoint Event The default.js file also includes an event handler for the WinJS.Application checkpoint event: app.oncheckpoint = function (eventObject) { // TODO: This application is about to be suspended. Save any state // that needs to persist across suspensions here. You might use the // WinJS.Application.sessionState object, which is automatically // saved and restored across suspension. If you need to complete an // asynchronous operation before your application is suspended, call // eventObject.setPromise(). }; The checkpoint event is raised when your Metro application goes into a suspended state. The idea is that you can save your application data when your application is suspended and reload your application data when your application resumes. Starting the Application The final statement in the default.js file is the statement that gets everything going: app.start(); Events are queued up in a JavaScript array named eventQueue . Until you call the start() method, the events in the queue are not processed. If you don’t call the start() method then the Loaded, Activated, Ready, and Unloaded events are never raised. Summary The goal of this blog entry was to describe the contents of the default.js file which is the JavaScript file which you use to kick off your custom code in a Windows Metro style application written with JavaScript. In this blog entry, I discussed the module pattern, JavaScript strict mode, handling first chance exceptions, WinJS Application events, and activation contexts.

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