ModuleCatalog

Purpose

This module provides an AggregateModuleCatalog class that implements the Prism IModuleCatalog interface to aggregate multiple module catalogs into a single unified catalog. It enables the application to combine modules from different catalog sources (e.g., configuration-based, directory-based, or dynamically loaded catalogs) while presenting them through a single interface to the Prism modularity system.

Public Interface

Class: AggregateModuleCatalog (implements IModuleCatalog)

AggregateModuleCatalog() - Constructor that initializes the aggregate catalog with a default Microsoft.Practices.Prism.Modularity.ModuleCatalog as the first catalog.
void AddCatalog(IModuleCatalog catalog) - Adds a module catalog to the aggregate. Throws ArgumentNullException if catalog is null.
IEnumerable<ModuleInfo> Modules (property) - Returns all ModuleInfo instances across all aggregated catalogs via SelectMany.
IEnumerable<ModuleInfo> GetDependentModules(ModuleInfo moduleInfo) - Returns dependent modules for the given moduleInfo by locating the owning catalog and delegating the call. Uses Single() to find the catalog containing the module.
IEnumerable<ModuleInfo> CompleteListWithDependencies(IEnumerable<ModuleInfo> modules) - Returns a complete list of modules including all dependencies. Groups modules by their owning catalog and delegates to each catalog's CompleteListWithDependencies.
void Initialize() - Initializes all aggregated catalogs by calling Initialize() on each.
void AddModule(ModuleInfo moduleInfo) - Adds a ModuleInfo to the first catalog in the list (_catalogs[0]).

Invariants

The _catalogs list is never null; it is initialized in the constructor and always contains at least one catalog (the default ModuleCatalog).
The first catalog (_catalogs[0]) is always an instance of Microsoft.Practices.Prism.Modularity.ModuleCatalog.
AddCatalog will throw ArgumentNullException if passed a null catalog.
GetDependentModules assumes each ModuleInfo exists in exactly one catalog; behavior is undefined if a module appears in multiple catalogs.

Dependencies

Depends on:

Microsoft.Practices.Prism.Modularity - IModuleCatalog, ModuleCatalog, ModuleInfo

Depended on by:

Not determinable from source alone; likely consumed by application bootstrapping/initialization code.

Gotchas

AddModule always adds to the first catalog only (_catalogs[0]), not to all catalogs or a user-specified catalog. This may cause confusion if developers expect modules to be distributed across catalogs.
GetDependentModules uses Single() which will throw InvalidOperationException if the module is not found in any catalog or exists in multiple catalogs.
The XML documentation comments reference DataPro.Main.ModuleCatalog which appears to be a stale/incorrect reference; the actual class is

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