Pro Silverlight 5 in VB potx

MacDonald Shelve in .NET User level: Intermediate–Advanced www.apress.com SOURCE CODE ONLINE RELATED BOOKS FOR PROFESSIONALS BY PROFESSIONALS ® Pro Silverlight 5 in VB Silverlight is a revolutionary browser plug-in. Using it, you can create rich client appli- cations that run inside the browser. Impressively, Silverlight applications have cross- platform reach—they run seamlessly in non-Microsoft browsers (like Firefox, Safari, and Chrome) and work on both the Windows and Mac OS operating systems. And best of all, Silverlight applications support pure VB code and use a streamlined version of the .NET Framework. In this book, you’ll learn to: • Develop rich applications that work on all desktop browsers • Design modern user interfaces with Silverlight’s layout tools and fully-stocked control toolkit • Create cutting-edge effects with 2D drawing, 3D drawing, and animation • Incorporate sound and video • Query a database through an ASP.NET web service, and display the records with data binding • Master advanced features like multithreading and networking • Create desktop-like applications that run in their own windows This book is for .NET developers encountering Silverlight for the first time. No Silverlight experience is required—but if you’ve worked with earlier Silverlight versions, you’ll appreciate the “What’s New” boxes that point out new features at the start of every chapter. By the end of this book, you’ll have a solid understanding of the complete Silverlight platform, and you’ll be able to build anything from a slick business front-end to a browser-based game. For your convenience Apress has placed some of the front matter material after the index. Please use the Bookmarks and Contents at a Glance links to access them. iv Contents at a Glance  About the Author xxvii  About the Technical Reviewer xxviii  Acknowledgments xxix  Introduction xxx  Chapter 1: Introducing Silverlight 1  Chapter 2: XAML 35  Chapter 3: Layout 63  Chapter 4: Dependency Properties and Routed Events 111  Chapter 5: Elements 143  Chapter 6: The Application Model 205  Chapter 7: Navigation 233  Chapter 8: Shapes and Transforms 265  Chapter 9: Brushes, Bitmaps, and Printing 315  Chapter 10: Animation Basics 349  Chapter 11: Advanced Animation 377  Chapter 12: Sound, Video, and Deep Zoom 411  Chapter 13: Silverlight 3D 467  Chapter 14: Styles and Behaviors 511  Chapter 15: Control Templates 539  Chapter 16: Multithreading 583  Chapter 17: Browser Integration 605  Chapter 18: Out-of-Browser Applications 631  Chapter 19: ASP.NET Web Services 679  CONTENTS v  Chapter 20: Data Binding 709  Chapter 21: Data Controls 763  Chapter 22: File Access 825  Chapter 23: Networking 857  Index 905 xxx Introduction Silverlight is a framework for building rich, browser-hosted applications that run on a variety of operating systems. Silverlight works its magic through a browser plug-in. When you surf to a web page that includes Silverlight content, this browser plug-in runs, executes the code, and renders that content in a specifically designated region of the page. The important part is that the Silverlight plug-in provides a richer environment than the traditional blend of HTML and JavaScript that powers ordinary web pages. Used carefully and artfully, you can create Silverlight pages that play video, have hardware- accelerated 3D graphics, and use vector animations. Understanding Silverlight Silverlight uses a familiar technique to go beyond the capabilities of standard web pages: a lightweight browser plug-in. The advantage of the plug-in model is that the user needs to install just a single component to see content created by a range of different people and companies. Installing the plug-in requires a small download and forces the user to confirm the operation in at least one security dialog box. It takes a short but definite amount of time, and it’s an obvious inconvenience. However, once the plug-in is installed, the browser can process any content that uses the plug-in seamlessly, with no further prompting. Figure 1 shows two views of a page with Silverlight content. At the top is the page you’ll see if you don’t have the Silverlight plug-in installed. At this point, you can click the Get Microsoft Silverlight picture to be taken to Microsoft’s website, where you’ll be prompted to install the plug-in and then sent back to the original page. On the bottom is the page you’ll see once the Silverlight plug-in is installed.  INTRODUCTION xxxi Figure 1. Installing the Silverlight plug-in  INTRODUCTION xxxii  Note At the time of this writing, Silverlight 4 is installed on an estimated 75 percent of Internet-connected computers (including desktop and mobile devices). The share is higher if you consider only Windows operating systems or Internet Explorer browsers. Although this is impressive, it pales in comparison to Flash, which has version 10 or better installed on a staggering 96 percent of all web devices. (To get up-to-date statistics, refer to www.riastats.com.) Silverlight System Requirements With any web-centric technology, it’s keenly important to have compatibility with the widest possible range of computers and devices. And although Silverlight isn’t completely cross-platform, its compatibility stacks up well on the majority of desktop computers. Currently, Silverlight supports the following: • Windows computers: Silverlight works on PCs with Windows 7, Windows Vista, and Windows XP. The minimum browser versions that Silverlight supports are Internet Explorer 6, Firefox 1.5, and Google Chrome 4.0. Silverlight will also work in Windows 2000, but only with Internet Explorer 6. Other browsers, such as Opera and Safari (for Windows), aren’t currently supported. • Mac computers: Silverlight works on Mac computers with OS X 10.4.8 or newer, provided they have Intel hardware (as opposed to the older PowerPC hardware). The minimum browser versions that Silverlight supports are Firefox 2 and Safari 3. Silverlight does not run on mobile Apple devices, which includes the iPhone, iPod Touch, and iPad. • Linux computers: Although Silverlight 5 doesn’t work on Linux, the Mono team has created an open source Linux implementation called Moonlight. The last officially released version supports Silverlight 2 applications, although there is also a released preview version that supports Silverlight 4. Progress is slow, and it’s uncertain when (and if) there will be a Moonlight that supports Silverlight 5. • Windows Phone: Silverlight is also one of two development frameworks for Windows Phone 7 (the other being the game-focused Microsoft XNA). However, developing for Windows Phone raises some unique considerations, and there are some subtle feature differences. To learn more about WP7 development, you can refer to a dedicated book, like Pro Windows Phone 7 Development. Installing Silverlight requires a small-sized setup (around 6MB) that’s easy to download. That allows it to provide an all-important “frictionless” setup experience, much like Flash. Silverlight vs. Flash The most successful browser plug-in is Adobe Flash, which is installed on more than 90 percent of the world’s web browsers. Flash has a long history that spans more than ten years, beginning as a  INTRODUCTION xxxiii straightforward tool for adding animated graphics and gradually evolving into a platform for developing interactive content. It’s perfectly reasonable for .NET developers to create websites that use Flash content. However, doing so requires a separate design tool and a completely different programming language (ActionScript) and programming environment (Flex). Furthermore, there’s no straightforward way to integrate Flash content with server-side .NET code. For example, creating Flash applications that call .NET components is awkward at best. Using server-side .NET code to render Flash content (for example, a custom ASP.NET control that spits out a Flash content region) is far more difficult. That’s where Silverlight fits into the picture. Silverlight aims to combine the raw power and cross- platform support of Flash with a first-class programming platform that incorporates the fundamental concepts of .NET. As a result, developers can write client-side code for Silverlight in the same language they use for server-side code (such as C# and VB), and they use many of the same abstractions (including streams, controls, collections, generics, and LINQ). In short, for .NET developers Silverlight is both a more convenient and a more powerful choice for rich Internet applications. Silverlight vs. HTML5 When Silverlight was first created, it was intended as an all-purpose way to build rich web pages and a competitor to Adobe Flash. However, in the several Silverlight versions since, the world has changed. Although Adobe Flash is still supported by virtually every desktop computer, it’s been locked out of popular Apple products like the iPhone and iPad. As a result, the mobile world is gravitating to different solutions, including native applications (which are limited to just one operating system) or HTML5. A broad consensus exists that HTML5 is the future of the Web, someday. However, the features that HTML5 promises (when it’s fully adopted) still fall far short of the features that are available today in Flash and Silverlight. For some applications, these shortcomings don’t matter. And, without doubt, the capabilities of HTML5 will strengthen in the future. But in the meantime, developers are forced to choose between features now, if they need them (in which case they’re likely to pick Silverlight) and the broadest possible compatibility for all computers and mobile devices (in which case they’ll probably prefer HTML5). This dilemma is also described as rich versus reach. Silverlight is the rich side of this equation—it gives applications the most powerful and mature feature set. HTML5 is the reach, because it embraces every modern desktop browser. Because of this upheaval, many Silverlight developers are uncertain about exactly where their favorite technology fits into the world of web development. And while the future is far from certain, here are a few points to keep in mind: HTML5 isn’t quite here yet: HTML5 support lags in in Internet Explorer. Many HTML5 features are promised for the not-yet-released IE 10, some features are available in the relatively recent IE 9, but IE 8 has no HTML5 smarts. This is a problem, because IE 8 is the best version of IE that can run on the still-widespread Windows XP platform. For all these reasons, HTML5 remains currently has less support than Silverlight, and this situation may take years to change. Silverlight has features that have no HTML5 equivalent: Even in the browsers that offer the best possible HTML5 support fall behind Silverlight in a few key areas. They can’t offer the same video streaming features, the same hardware-accelerated graphics, or the same deep networking support. Nor do they support file access, out-of-browser applications, or the ability to call Windows system components. And it’s hard to imagine HTML5 ever duplicating some of Silverlight’s more specialized features, like the PivotViewer control that fuses together data filtering, fluid animations, and image scaling in one easy-to-use package (Chapter 21).  INTRODUCTION xxxiv Silverlight has a higher-level programming API: Features such as data binding, styles, and templates may not be essential for building an application, but they are important for building one quickly and efficiently. Many things that are possible in HTML5 are a manageability nightmare in all but the most disciplined hands. The JavaScript language is notoriously lax in letting syntax errors slide, all animation routines must be written by hand, and multithreading support is clumsy at best. Silverlight has top-tier development tools: Thanks to Visual Studio, you can build a Silverlight application just as easily as you build a desktop program. Add Expression Blend to the picture, and you also have a way to define and customize rich graphical effects, like animations. Silverlight offers ASP.NET integration: In particular, Silverlight makes it easy to query server-side databases through a web service. This state of affairs has led some developers to speculate that even when HTML5 does finally conquer the world, Silverlight will remain as a first choice for line-of- business development inside closed company networks. No one’s quite sure of Silverlight’s future. It may continue on as a first-choice platform for .NET developers creating business applications, or it may gradually transition into a more specialized tool for cutting-edge games and video players. One thing is settled, however: Silverlight will never replace HTML as the main language for creating traditional, public websites—nor does it intend to. Silverlight vs. Metro (and Windows 8) When Microsoft announced Windows 8, complete with yet another programming model for rich client applications, Silverlight developers paused. Some wondered if that technology—named Metro—would be an eventual Silverlight replacement. The answer is clearly “no.” Metro is designed to facilitate an entirely different sort of application: a lightweight, touch-centric, data-consuming application that can run on the future generation of Windows 8–powered tablets. In a very real sense, Metro is a competitor to native apps on the iPad, as well as a potential successor to Microsoft’s other rich desktop programming framework, WPF (see the next section). However, Metro applications have no ability to run on non-Microsoft platforms—or any version of Windows other than Windows 8. For that reason, they are of little interest to Silverlight developers. In the future, the range of Silverlight applications may narrow, squeezed between cross-platform HTML5 applications that are gradually growing more sophisticated and native Metro or iPad applications for mobile devices. However, today Silverlight still occupies the very important space between these other technologies. Silverlight and WPF One of the most interesting aspects of Silverlight is the fact that it borrows the model WPF uses for rich, client-side user interfaces. WPF is a toolkit for building rich Windows applications. WPF is notable because it not only simplifies development with a powerful set of high-level features, it also increases performance by rendering everything through the DirectX pipeline. To learn about WPF, you can refer to Pro WPF in VB 2010 (Apress). Silverlight obviously can’t duplicate the features of WPF, because many of them rely deeply on the capabilities of the operating system, including Windows-specific display drivers and DirectX technology. However, rather than invent an entirely new set of controls and classes for client-side development,  INTRODUCTION xxxv Silverlight uses a subset of the WPF model. If you’ve had any experience with WPF, you’ll be surprised to see how closely Silverlight resembles its big brother. Here are a few common details: • To define a Silverlight user interface (the collection of elements that makes up a Silverlight content region), you use XAML markup, just as you do with WPF. You can even map data to your display using the same data-binding syntax. • Silverlight borrows many of the same basic controls from WPF, along with the same styling system (for standardizing and reusing formatting) and a similar templating mechanism (for changing the appearance of standard controls). • To draw 2D graphics in Silverlight, you use shapes, paths, transforms, geometries, and brushes, all of which closely match their WPF equivalents. • Silverlight provides a declarative animation model that’s based on storyboards and works in the same way as WPF’s animation system. • To show video or play audio files, you use the MediaElement class, as you do in WPF.  Note WPF is not completely cut off from the easy deployment world of the Web. WPF allows developers to create browser-hosted applications called XBAPs (XAML Browser Applications). These applications are downloaded seamlessly, cached locally, and run directly inside the browser window, all without security prompts. However, although XBAPs run in Internet Explorer and Firefox, they are still a Windows-only technology, unlike Silverlight. The Evolution of Silverlight Silverlight 1 was a relatively modest technology. It included 2D drawing features and media playback support. However, it didn’t include the CLR engine or support for .NET languages, so developers were forced to code in JavaScript. Silverlight 2 was a dramatic change. It added the CLR, a subset of .NET Framework classes, and a user interface model based on WPF. As a result, Silverlight 2 was one of the most hotly anticipated releases in Microsoft’s history. The versions of Silverlight since haven’t been as ambitious. Silverlight 5 keeps the same development model that was established in Silverlight 2 but adds a carefully selected group of features and performance enhancements. They highlights include the following: • Performance improvements: Silverlight 5 starts faster, supports 64-bit browsers, and provides cleaner, crisper text rendering at small sizes. • Vector printing: Silverlight improves its printing model to use vector printing, when possible (namely, if the print driver supports PostScript). The result is faster printing with less memory overhead (Chapter 9). [...]... Your Silverlight project is compiled into a DLL file named after your project For example, if you have a project named SilverlightApplication1, the vbc.exe compiler will create the file SilverlightApplication1.dll The project assembly is dumped into a Bin\Debug folder in your project directory, along with a few other important files: 18 CHAPTER 1  INTRODUCING SILVERLIGHT • A PDB file: This file contains... as debugging, code refactoring, and project source control  Note Visual Studio 2010 includes full support for creating Silverlight 3 projects But to create Silverlight 5 projects, you need the Silverlight 5 Tools for Visual Studio 2010 And if you plan to use Expression Blend with Silverlight 5, you’ll (currently) need to use a beta version called the Expression Blend Preview for Silverlight 5 You can... as playing a game, completing a survey, interacting with a product, or taking a virtual tour) You may use Silverlightenhanced pages to present content that’s already available in your website in a more engaging way or to provide a value-added feature for users who have the Silverlight plug -in Of course, it’s also possible to create a Silverlight- only website, which is a somewhat more daring approach... change the version of Silverlight that you’re targeting at any point after you’ve created it To do so, just double-click the My Project node in the Solution Explorer, and change the selection in the Target Silverlight Version list 4 4 Click OK to continue and create the project CHAPTER 1  INTRODUCING SILVERLIGHT Figure 1-1 Choosing not to include an ASP.NET website Every Silverlight project starts with... COMPATIBILITY IN SILVERLIGHT 5 At this point, you might be wondering if older Silverlight applications can run on a computer that has only the latest version of the Silverlight plug -in (version 5) installed It’s a reasonable question, because Silverlight 5 introduces some subtle changes and bug fixes that can influence the way applications work— and even change its behavior However, Silverlight 5 prevents... differences from causing problems by using its quirks mode feature When the Silverlight 5 plug -in loads an application that was compiled for an earlier version of Silverlight, it automatically switches into a quirks mode that attempts to emulate the behavior of the appropriate Silverlight runtime environment For more detailed information about breaking changes between Silverlight 5 and Silverlight 4, you... is that Silverlight isn’t installed as widely as other web technologies such as Flash, and doesn’t support legacy clients such as those running the Windows ME or Windows 2000 operating system As a result, Silverlight doesn’t have nearly the same reach as ordinary HTML Many businesses that are adopting Silverlight are using it to distinguish themselves from other online competitors with cutting-edge... they aren’t abandoning their traditional websites 3 CHAPTER 1  INTRODUCING SILVERLIGHT Creating a Stand-Alone Silverlight Project The easiest way to start using Silverlight is to create an ordinary website with HTML pages and no serverside code Here’s how: 1 Select File  New  Project in Visual Studio, choose the Visual Basic  Silverlight group of project types, and then select the Silverlight Application... experimenting, or take a look through Microsoft’s Expression Blend training videos at http://expression.microsoft.com/cc13 653 5.aspx Understanding Silverlight Websites You can create two types of Silverlight websites in Visual Studio or Expression Blend: • 2 An ordinary website with HTML pages: In this case, the entry point to your Silverlight application is a basic HTML file that includes a Silverlight. .. vantage point 7 CHAPTER 1  INTRODUCING SILVERLIGHT Figure 1-4 Viewing XAML pages You can start designing a XAML page by selecting a control in the Toolbox and then “drawing” it onto the design surface However, this convenience won’t save you from learning the full intricacies of XAML To organize your elements into the right layout containers, change their properties, wire up event handlers, and use Silverlight . MacDonald Shelve in .NET User level: Intermediate–Advanced www.apress.com SOURCE CODE ONLINE RELATED BOOKS FOR PROFESSIONALS BY PROFESSIONALS ® Pro Silverlight 5 in VB Silverlight. service for Silverlight in Chapter 19. ADDING SILVERLIGHT CONTENT TO AN EXISTING WEBSITE A key point to keep in mind when considering the Silverlight