《Prism 5.0源码走读》Bootstrapper

Prism框架需要在应用程序启动的时候进行一些初始化的工作，Bootstrapper就是来做这些的，是其切入点。

Bootstrapper主要要做的事有：创建和配置module catalog，创建DI Container，为UI配置默认的region适配器，创建和初始化shell以及初始化module。

    /// <summary>
    /// Base class that provides a basic bootstrapping sequence and hooks
    /// that specific implementations can override
    /// </summary>
    /// <remarks>
    /// This class must be overridden to provide application specific configuration.
    /// </remarks>
    public abstract class Bootstrapper
    {
        /// <summary>
        /// Gets the <see cref="ILoggerFacade"/> for the application.
        /// </summary>
        /// <value>A <see cref="ILoggerFacade"/> instance.</value>
        protected ILoggerFacade Logger { get; set; }

        /// <summary>
        /// Gets the default <see cref="IModuleCatalog"/> for the application.
        /// </summary>
        /// <value>The default <see cref="IModuleCatalog"/> instance.</value>
        protected IModuleCatalog ModuleCatalog { get; set; }

        /// <summary>
        /// Gets the shell user interface
        /// </summary>
        /// <value>The shell user interface.</value>
        protected DependencyObject Shell { get; set; }

        /// <summary>
        /// Create the <see cref="ILoggerFacade" /> used by the bootstrapper.
        /// </summary>
        /// <remarks>
        /// The base implementation returns a new TextLogger.
        /// </remarks>
        [System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Reliability", "CA2000:Dispose objects before losing scope", Justification = "The Logger is added to the container which will dispose it when the container goes out of scope.")]
        protected virtual ILoggerFacade CreateLogger()
        {
            return new TextLogger();
        }

        /// <summary>
        /// Runs the bootstrapper process.
        /// </summary>
        public void Run()
        {
            this.Run(true);
        }


        /// <summary>
        /// Creates the <see cref="IModuleCatalog"/> used by Prism.
        /// </summary>
        ///  <remarks>
        /// The base implementation returns a new ModuleCatalog.
        /// </remarks>
        protected virtual IModuleCatalog CreateModuleCatalog()
        {
            return new ModuleCatalog();
        }

        /// <summary>
        /// Configures the <see cref="IModuleCatalog"/> used by Prism.
        /// </summary>
        protected virtual void ConfigureModuleCatalog()
        {
        }

        /// <summary>
        /// Registers the <see cref="Type"/>s of the Exceptions that are not considered 
        /// root exceptions by the <see cref="ExceptionExtensions"/>.
        /// </summary>
        protected virtual void RegisterFrameworkExceptionTypes()
        {
            ExceptionExtensions.RegisterFrameworkExceptionType(
                typeof(Microsoft.Practices.ServiceLocation.ActivationException));
        }

        /// <summary>
        /// Initializes the modules. May be overwritten in a derived class to use a custom Modules Catalog
        /// </summary>
        protected virtual void InitializeModules()
        {
            IModuleManager manager = ServiceLocator.Current.GetInstance<IModuleManager>();
            manager.Run();
        }

        /// <summary>
        /// Configures the default region adapter mappings to use in the application, in order
        /// to adapt UI controls defined in XAML to use a region and register it automatically.
        /// May be overwritten in a derived class to add specific mappings required by the application.
        /// </summary>
        /// <returns>The <see cref="RegionAdapterMappings"/> instance containing all the mappings.</returns>
        protected virtual RegionAdapterMappings ConfigureRegionAdapterMappings()
        {
            RegionAdapterMappings regionAdapterMappings = ServiceLocator.Current.GetInstance<RegionAdapterMappings>();
            if (regionAdapterMappings != null)
            {
                regionAdapterMappings.RegisterMapping(typeof(Selector), ServiceLocator.Current.GetInstance<SelectorRegionAdapter>());
                regionAdapterMappings.RegisterMapping(typeof(ItemsControl), ServiceLocator.Current.GetInstance<ItemsControlRegionAdapter>());
                regionAdapterMappings.RegisterMapping(typeof(ContentControl), ServiceLocator.Current.GetInstance<ContentControlRegionAdapter>());
            }

            return regionAdapterMappings;
        }

        /// <summary>
        /// Configures the <see cref="IRegionBehaviorFactory"/>. 
        /// This will be the list of default behaviors that will be added to a region. 
        /// </summary>
        protected virtual IRegionBehaviorFactory ConfigureDefaultRegionBehaviors()
        {
            var defaultRegionBehaviorTypesDictionary = ServiceLocator.Current.GetInstance<IRegionBehaviorFactory>();

            if (defaultRegionBehaviorTypesDictionary != null)
            {
                defaultRegionBehaviorTypesDictionary.AddIfMissing(BindRegionContextToDependencyObjectBehavior.BehaviorKey,
                                                                  typeof(BindRegionContextToDependencyObjectBehavior));

                defaultRegionBehaviorTypesDictionary.AddIfMissing(RegionActiveAwareBehavior.BehaviorKey,
                                                                  typeof(RegionActiveAwareBehavior));

                defaultRegionBehaviorTypesDictionary.AddIfMissing(SyncRegionContextWithHostBehavior.BehaviorKey,
                                                                  typeof(SyncRegionContextWithHostBehavior));

                defaultRegionBehaviorTypesDictionary.AddIfMissing(RegionManagerRegistrationBehavior.BehaviorKey,
                                                                  typeof(RegionManagerRegistrationBehavior));

                defaultRegionBehaviorTypesDictionary.AddIfMissing(RegionMemberLifetimeBehavior.BehaviorKey,
                                                  typeof(RegionMemberLifetimeBehavior));

                defaultRegionBehaviorTypesDictionary.AddIfMissing(ClearChildViewsRegionBehavior.BehaviorKey,
                                                  typeof(ClearChildViewsRegionBehavior));

                defaultRegionBehaviorTypesDictionary.AddIfMissing(AutoPopulateRegionBehavior.BehaviorKey,
                                                  typeof(AutoPopulateRegionBehavior));
            }

            return defaultRegionBehaviorTypesDictionary;
        }

        /// <summary>
        /// Initializes the shell.
        /// </summary>
        protected virtual void InitializeShell()
        {
        }

        /// <summary>
        /// Run the bootstrapper process.
        /// </summary>
        /// <param name="runWithDefaultConfiguration">If <see langword="true"/>, registers default 
        /// Prism Library services in the container. This is the default behavior.</param>
        public abstract void Run(bool runWithDefaultConfiguration);

        /// <summary>
        /// Creates the shell or main window of the application.
        /// </summary>
        /// <returns>The shell of the application.</returns>
        /// <remarks>
        /// If the returned instance is a <see cref="DependencyObject"/>, the
        /// <see cref="Bootstrapper"/> will attach the default <see cref="IRegionManager"/> of
        /// the application in its <see cref="RegionManager.RegionManagerProperty"/> attached property
        /// in order to be able to add regions by using the <see cref="RegionManager.RegionNameProperty"/>
        /// attached property from XAML.
        /// </remarks>
        protected abstract DependencyObject CreateShell();

        /// <summary>
        /// Configures the LocatorProvider for the <see cref="Microsoft.Practices.ServiceLocation.ServiceLocator" />.
        /// </summary>
        protected abstract void ConfigureServiceLocator();
    }