MSDN Magazine - September 2008 - (Page 76)

Figure 7 UI Composition via RegionManager new AllActiveRegion instance. Regions can contain views that are active or inactive. In the case of the ItemsControl, all of its items are active all the time because it does not have a notion of selection. However, in the case of other types of regions, such as Selector, only one item is selected at a time. A view can implement the IActiveAware interface so that it is notified by its region that it is selected. Whenever the view is selected, it will have its IsSelected property set to true. Throughout the development of your composite application, you may have to create additional regions and region adapters, such as one that will adapt a control from a third-party vendor. To register your new region adapter, override the ConfigureRegionAdapterMappings method in the bootstrapper. Once that is done, add code similar to the following: protected override RegionAdapterMappings ConfigureRegionAdapterMappings() { RegionAdapterMappings regionAdapterMappings = base.ConfigureRegionAdapterMappings(); regionAdapterMappings.RegisterMapping(typeof(Selector), new MyWizBangRegionAdapter()); } return regionAdapterMappings; of the view can be displayed at the same time. If these views are fairly complex, they behave like mini-shells or CompositeViews. In these cases, you may want each view to have its own regions, as the shell does. The CAL allows you to define a local RegionManager for a view so that any regions defined within it or its child views are automatically registered in that local region. The UI Composition quickstart included with the guidance illustrates this employee scenario (see Figure 7). In the quickstart there is an employee list. As you click on each employee, you see the associated employee detail. For each employee selection, a new EmployeeDetailsView is created for that employee and added to the DetailsRegion (see Figure 8). This view contains a local TabRegion, into which the EmployeesController injects a ProjectListView in its OnEmployeeSelected method. The region is rendered as a TabControl and contains both static and dynamic content. The General and Location tabs are statically defined within the XAML. The Current Projects tab, however, has its views injected. You can see in the code that a new RegionManager instance is returned from the detailsRegion.Add method. Also notice that I am using the overload of Add that passes in a name for the view and sets the createRegionManagerScope parameter to true. Doing this creates a local RegionManager instance that will be used for any regions defined in the children. The TabRegion itself is defined in the XAML of the EmployeeDetailsView: Using local regions provides an additional benefit even if you are not using instance regions. You can use them for defining a toplevel boundary so that a module does not automatically expose its regions to the rest of the world. To do this, all you need is to add Figure 8 Creating a New Employee View public virtual void OnEmployeeSelected(BusinessEntities.Employee employee) { IRegion detailsRegion = regionManager.Regions[RegionNames.DetailsRegion]; object existingView = detailsRegion.GetView( employee.EmployeeId.ToString(CultureInfo.InvariantCulture)); if (existingView == null) { IProjectsListPresenter projectsListPresenter = this.container.Resolve (); projectsListPresenter.SetProjects(employee.EmployeeId); IEmployeesDetailsPresenter detailsPresenter = this.container.Resolve (); detailsPresenter.SetSelectedEmployee(employee); IRegionManager detailsRegionManager = detailsRegion.Add(detailsPresenter.View, employee.EmployeeId.ToString(CultureInfo.InvariantCulture), true); IRegion region = detailsRegionManager.Regions[RegionNames.TabRegion]; region.Add(projectsListPresenter.View, "CurrentProjectsView"); detailsRegion.Activate(detailsPresenter.View); Once the region has been defined, it can be accessed from any class within the application by grabbing hold of the RegionManager service. The common way to do this in a CAL application is to have the dependency injection container inject the RegionManager into the constructor of the class that needs it. To add a view or model to a region, simply call the region’s Add method. When you add a view, you can pass an optional name: _regionManager.Regions["MainRegion"].Add( somePresentationModel, "SomeView"); You can later use that name to retrieve the view from the region by using the region’s GetView method. Locally Scoped Regions By default, there is only one RegionManager instance in your application, thereby making every region globally scoped. This addresses a wide set of scenarios, but there are situations where you may want to define a region that exists only at a particular scope. An example of where you might want to do this is when your application has a view for employee details where multiple instances 76 msdn magazine } } else { detailsRegion.Activate(existingView); } Composite WPF

Table of Contents Feed for the Digital Edition of MSDN Magazine - September 2008

MSDN Magazine - September 2008 Contents Toolbox CLR Inside Out Data Points Advanced Basics Office Space Cutting Edge Hierarchy ID New Features for Microsoft SQL Server 2008 Prism Data Services Advanced WPF Test Run Security Briefs Foundations { End Bracket }

MSDN Magazine - September 2008

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