Lập trình .net 4.0 và visual studio 2010 part 57 pdf

CHAPTER 15  WPF 4.0 AND SILVERLIGHT 3.0 377 New Controls WPF 4.0 now contains the DataGrid, Calendar, and DatePicker controls that were previously available as part of the WPF toolkit. Microsoft says that these controls are nearly 100 percent compatible with their Silverlight relations. Figure 15-16 shows the new Calendar and DatePicker controls; Figure 15-17 shows the DataGrid control in action. Figure 15-16. Calendar and DatePicker controls Figure 15-17. DataGrid control The easiest way to create these controls is to drag them from the toolbox or add them manually with the following XAML: <Calendar></Calendar> <DatePicker/> <DataGrid></DataGrid> CHAPTER 15  WPF 4.0 AND SILVERLIGHT 3.0 378 Ribbon Control and Bag O’Tricks Microsoft says that shortly after the release of VS2010 it will introduce a new WPF Ribbon control. The Ribbon control could work particularly well in conjunction with the new touchscreen APIs. A CTP of the Ribbon control is available at http://wpf.codeplex.com/Release/ProjectReleases.aspx?ReleaseId=29117. Microsoft will also be making an out-of-band release that will contain the following controls under the collection name “Bag O’Tricks” (sorry, no information is available at time of writing, although judging by the control names you can have a pretty good guess at what they do): • AnimatingTilePanel • NumericUpDown • ColorPicker • Reveal • InfoTextBox • TransitionsPresenter • ListPager • TreeMapPanel Windows 7 Integration Windows 7 has some great new UI features such as jump lists, taskbar overlays, and progress indicators. WPF 4.0 allows you to add these features to your applications. It is also worth noting that in this release WPF dialogs now have the same feel of Vista and Windows 7 (depending what they are running on). Jump Lists Jump lists, which allow you to easily perform common tasks, are activated by right-clicking an application on the task bar. Figure 15-18 shows the jump list for Windows Live Messenger. Figure 15-18. Jump list in Windows 7 CHAPTER 15  WPF 4.0 AND SILVERLIGHT 3.0 379 Like most things in WPF/Silverlight, jump lists can be created programmatically and declaratively. The following code shows how to create a jump list to open Internet Explorer and Notepad that you would define in your MainWindow.xaml: using System.Windows.Shell; JumpList appJumpList = new JumpList(); //Configure a JumpTask JumpTask jumpTask1 = new JumpTask(); jumpTask1.ApplicationPath = @"C:\Program Files (x86)\Internet Explorer\iexplore.exe"; jumpTask1.IconResourcePath = @"C:\Program Files (x86)\Internet Explorer\iexplore.exe"; jumpTask1.Title = "IE"; jumpTask1.Description = "Open IE"; JumpTask jumpTask2 = new JumpTask(); jumpTask2.ApplicationPath = @"C:\Windows\System32\notepad.exe"; jumpTask2.IconResourcePath = @"C:\Windows\System32\notepad.exe"; jumpTask2.Title = "Notepad"; jumpTask2.Description = "Open Notepad"; appJumpList.JumpItems.Add(jumpTask1); appJumpList.JumpItems.Add(jumpTask2); JumpList.SetJumpList(App.Current, appJumpList); Task Bar Windows 7 applications can communicate progress and application status via the task bar. For example, Figure 15-19 shows IE indicating download progress. Figure 15-19. IE indicating download progress WPF 4.0 Windows 7 task bar APIs give you control over the following: • Progress bar overlay (refer to Figure 15-19). • Icon overlay through the Overlay property (e.g., a small picture). • Thumbnail window (a window that pops up showing a miniview of the application's window). Note that you can pick which bit of the window is shown using the ThumbnailClipMargin property. Let’s take a look at how to work with the progress bar. The progress bar allows you to specify a double value between 0 and 1 to indicate your application's progress with the ProgressValue property. You can also indicate different types of status by specifying the ProgressState property. This has five different settings that change the color of the bar: CHAPTER 15  WPF 4.0 AND SILVERLIGHT 3.0 380 • Error (red) • Indeterminate (green) • None (not shown) • Normal (green) • Paused (yellow) You will now see how to work with this by setting a progress bar at 50% for the application: 1. Create a new WPF application called Chapter15.ProgressBar. 2. Open MainWindow.xaml.cs and add the following using statement: using System.Windows.Shell; 3. Amend the code to the following: public MainWindow() { InitializeComponent(); this.Loaded += new RoutedEventHandler(MainWindow_Loaded); } void MainWindow_Loaded(object sender, RoutedEventArgs e) { TaskbarItemInfo taskBarItemInfo = new TaskbarItemInfo(); taskBarItemInfo.ProgressState = TaskbarItemProgressState.Normal; this.TaskbarItemInfo = taskBarItemInfo; taskBarItemInfo.ProgressValue = 0.5d; } 4. If you now run your application, you should find the progress bar at 50%. Multitouch Functionality Probably one of the most interesting features in WPF 4.0 is multitouch functionality. Multitouch allows your application to work with touch input and gestures (e.g., you can spin an image around by rotating your hand). Multitouch support is Windows 7 only and is enabled by setting the IsManipulationEnabled property on an element to true and then handling the various events that the APIs expose. It's worth noting that multitouch functionality is compatible with Surface SDK 2.0 (the world’s most expensive but cool table). ContentElement, UIElement, and UIElement3D elements support the following events: • PreviewTouchDown • TouchDown • PreviewTouchMove • TouchMove CHAPTER 15  WPF 4.0 AND SILVERLIGHT 3.0 381 • PreviewTouchUp • TouchUp • GotTouchCapture • LostTouchCapture • TouchEnter • TouchLeave Besides simple touch-related events WPF4.0 also supports various gestures. You can restrict the manipulations that can be performed in the ManipulationStarted event by specifying the ManipulationMode. WPF4.0 supports the following gesture-related events: • ManipulationStarted • ManipulationDelta • ManipulationInertiaStarting • ManipulationCompleted • ManipulationBoundaryFeedback At present, hardware support for multitouch is a bit limited and expensive (and who wants grubby fingerprints on their monitors?), but expect this to rapidly change in 2010. Probably the best known multitouch device is the Dell Latitude XT2 and HP touchsmart. If you don’t want to fork out for one of these devices you could give the clever work around with two mice here: http://blog.wpfwonderland.com/2009/06/29/developing-win-7-multi-touch-apps-without-multi- touch-screen/ . MSDN has a good simple example demonstrating WPF’s touch functionality: http:// msdn.microsoft.com/en-us/library/ee649090(VS.100).aspx. Binding Changes Besides the very welcome new Binding window in VS2010, there are a number of other changes in the exciting world of binding. Run.text Run.text is now a dependency property, which means you can now bind to it (one way) unlike previous releases of WPF. Dynamic Binding Support WPF4.0 supports binding to properties implementing the IDynamicMetaObjectProvider interface such as ExpandoObject and anything inheriting from DynamicObject ( (see Chapter 3). CHAPTER 15  WPF 4.0 AND SILVERLIGHT 3.0 382 Input Bindings Now Support Bindings In previous releases of WPF, it was quite tricky to set binding to input keys using the InputBinding class. This was because the Command property was not a dependency property and also didn’t inherit the parent's data context. This could make certain scenarios such as implementing the MVVM pattern difficult. This is resolved in WPF 4.0. InputBinding, MouseBinding, and KeyBinding now inherit from Freezable and various related properties are now made dependency properties. This should then allow you to write input binding XAML such as the following: <Window.InputBindings> <KeyBinding Modifiers="Control" Key="L" Command="{Binding MyCustomCommand}" /> </Window.InputBindings> Text-Rendering Improvements In previous releases of WPF, text could sometimes appear a bit blurry. This is fixed in WPF 4.0 (possibly driven by the need for clear text in VS2010 IDE) and you now have much finer-grained control over how text is rendered with the new TextFormattingMode and TextRenderingMode properties. TextOptions.TextFormattingMode TextFormatting mode allows you to set the text metrics that WPF will use for formatting text. TextFormatting mode has two settings: • Ideal (as per previous versions) • Display (ensures that every glyph’s position and width is not fractional, which is very similar to how the GDI renders text) The following code demonstrates setting text to use the Display setting: <TextBlock TextOptions.TextFormattingMode="Display"> Hello I am using new Display mode formatting </TextBlock> Setting text to Display mode will in many cases make the text look darker and clearer. In Figure 15- 20 the first paragraph uses the old Ideal setting; the second uses the new Display setting (yes, the difference is subtle, especially in print, but try it for yourself). . functionality: http:// msdn.microsoft.com/en-us/library/ee 649 09 0(VS. 100 ).aspx. Binding Changes Besides the very welcome new Binding window in VS 201 0, there are a number of other changes in the exciting. <DataGrid></DataGrid> CHAPTER 15  WPF 4. 0 AND SILVERLIGHT 3 .0 378 Ribbon Control and Bag O’Tricks Microsoft says that shortly after the release of VS 201 0 it will introduce a new WPF Ribbon. CHAPTER 15  WPF 4. 0 AND SILVERLIGHT 3 .0 377 New Controls WPF 4. 0 now contains the DataGrid, Calendar, and DatePicker controls that were previously available as part of the WPF toolkit.