Bootstrap Conventions

As we have already said the whole bootstrap process is completely based on conventions, especially the IoC container setup. Bootstrap conventions are mainly related to the way components are registered into the container:

• every class that is defined in a namespace ending with Services (*.Services) will be considered a service and will be registered as singleton using as the service contract the first interface, if any, otherwise using the class type;

• every class that is defined in a namespace ending with Presentation (*.Presentation) and whose type name ends with ViewModel (*ViewModel) will be considered as a view model and registered as transient;

  • following the same logic every type in the same namespace whose name ends with View (*View) will be considered a view, a transient view;

  • if a view or a view model are a shell, type name beginning with Shell* or Main*, they will be registered as singleton

  • be default views and view models will be registered using as service contract the class type and no interface is searched along the way;

• every type defined in a namespace ending with Messaging.Handlers (*.Messaging.Handlers) will be considered a message broker message handler and will be registered as singleton and automatically attached, as an handler, to the broker pipeline;

These are the main conventions used at boot time, there are a few more but less important. Obviously all these behaviors can be replaced or extended to accomplish the end user needs:

public partial class App : Application
{
    public App()
    {
        var bootstrapper = new WindsorApplicationBootstrapper<MainView>()
            .OnBeforeInstall( conventions => 
            {
                var original = conventions.IsViewModel;
                conventions.IsViewModel = type => 
                {
                    if ( type.Namespace == "MyViewModelsNamespace" ) 
                    {
                        return true;
                    }

                    return original( type );
                };
            } );
    }
}

In the above sample we are integrating the conventions used to determine if a type is a view model.

The following is the list of the used conventions with a brief description of their meaning and usage:

• IsService: determines if a type should be considered a service or not;

• SelectServiceContracts: given the service type returns the list of contracts that should be used to register the given service;

• IsMessageHandler: determines if a type should be considered a message handler or not;

• SelectMessageHandlerContracts: given the message handler type returns the list of contracts that should be used to register the given message handler;

• IsView: determines if a type should be considered a view or not. The View is registered as transient in the IoC container;

• IsViewModel: determines if a type should be considered a view model or not. The ViewModel is registered as transient in the IoC container;

• IsShellView: determines if a type should be considered a shell/main view or not. The View is registered as singleton in the IoC container;

• IsShellViewModel: determines if a type should be considered a shell/main view model or not. The ViewModel is registered as singleton in the IoC container;

• SelectViewContracts: given the view type returns the list of contracts that should be used to register the given view;

• SelectViewModelContracts: given the view model type returns the list of contracts that should be used to register the given view model;

• IsExcluded: determines if a type should be excluded (ignored) by the registration process;

• GetInterestedRegionNameIfAny: this convention requires a deep knowledge of the UI Composition feature and is used to determine if a view is asking to be injected into a region, the conventions is used to retrieve the region name the view would like to be injected into;

• AssemblyFileScanPatterns: given the entry assembly returns a list of patterns that should be used by MEF directory catalogs to scan for assemblies at boot time;