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DirectoryCatalog Class

Discovers attributed parts in the assemblies in a specified directory.

System.Object
  System.ComponentModel.Composition.Primitives.ComposablePartCatalog
    System.ComponentModel.Composition.Hosting.DirectoryCatalog

Namespace:  System.ComponentModel.Composition.Hosting
Assembly:  System.ComponentModel.Composition (in System.ComponentModel.Composition.dll)

public class DirectoryCatalog : ComposablePartCatalog, 
	INotifyComposablePartCatalogChanged, ICompositionElement

The DirectoryCatalog type exposes the following members.

  NameDescription
Public methodDirectoryCatalog(String)Initializes a new instance of the DirectoryCatalog class by using ComposablePartDefinition objects based on all the DLL files in the specified directory path.
Public methodDirectoryCatalog(String, ICompositionElement)Initializes a new instance of the DirectoryCatalog class by using ComposablePartDefinition objects based on all the DLL files in the specified directory path with the specified source for parts.
Public methodDirectoryCatalog(String, ReflectionContext)Initializes a new instance of the DirectoryCatalog class by using ComposablePartDefinition objects based on all the DLL files in the specified directory path, in the specified reflection context.
Public methodDirectoryCatalog(String, String)Initializes a new instance of the DirectoryCatalog class by using ComposablePartDefinition objects that match a specified search pattern in the specified directory path.
Public methodDirectoryCatalog(String, ReflectionContext, ICompositionElement)Initializes a new instance of the DirectoryCatalog class by using ComposablePartDefinition objects based on all the DLL files in the specified directory path, in the specified reflection context.
Public methodDirectoryCatalog(String, String, ICompositionElement)Initializes a new instance of the DirectoryCatalog class by using ComposablePartDefinition objects based on the specified search pattern in the specified directory path with the specified source for parts.
Public methodDirectoryCatalog(String, String, ReflectionContext)Initializes a new instance of the DirectoryCatalog class by using ComposablePartDefinition objects based on the specified search pattern in the specified directory path, using the specified reflection context.
Public methodDirectoryCatalog(String, String, ReflectionContext, ICompositionElement)Initializes a new instance of the DirectoryCatalog class by using ComposablePartDefinition objects based on the specified search pattern in the specified directory path, using the specified reflection context.
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  NameDescription
Public propertyFullPathGets the translated absolute path observed by the DirectoryCatalog object.
Public propertyLoadedFilesGets the collection of files currently loaded in the catalog.
Public propertyPartsGets the part definitions that are contained in the catalog. (Inherited from ComposablePartCatalog.)

In .NET Framework Client Profile, this member is overridden by Parts.
Public propertyPathGets the path observed by the DirectoryCatalog object.
Public propertySearchPatternGets the search pattern that is passed into the constructor of the DirectoryCatalog object.
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  NameDescription
Public methodDispose()Releases all resources used by the ComposablePartCatalog. (Inherited from ComposablePartCatalog.)
Protected methodDispose(Boolean)Releases the unmanaged resources used by the DirectoryCatalog and optionally releases the managed resources. (Overrides ComposablePartCatalog.Dispose(Boolean).)
Public methodEquals(Object)Determines whether the specified object is equal to the current object. (Inherited from Object.)
Protected methodFinalizeAllows an object to try to free resources and perform other cleanup operations before it is reclaimed by garbage collection. (Inherited from Object.)
Public methodGetEnumeratorReturns an enumerator that iterates through the catalog. (Overrides ComposablePartCatalog.GetEnumerator().)
Public methodGetExportsGets the export definitions that match the constraint expressed by the specified import definition. (Overrides ComposablePartCatalog.GetExports(ImportDefinition).)
Public methodGetHashCodeServes as the default hash function. (Inherited from Object.)
Public methodGetTypeGets the Type of the current instance. (Inherited from Object.)
Protected methodMemberwiseCloneCreates a shallow copy of the current Object. (Inherited from Object.)
Protected methodOnChangedRaises the Changed event.
Protected methodOnChangingRaises the Changing event.
Public methodRefreshRefreshes the ComposablePartDefinition objects with the latest files in the directory that match the search pattern.
Public methodToStringGets a string representation of the directory catalog. (Overrides Object.ToString().)
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  NameDescription
Public eventChangedOccurs when the contents of the catalog has changed.
Public eventChangingOccurs when the catalog is changing.
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  NameDescription
Public Extension MethodCreateCompositionServiceCreates a new composition service by using the specified catalog as a source for exports. (Defined by CatalogExtensions.)
Public Extension MethodFilterFilters the specified catalog with the specified filter function. (Defined by ScopingExtensions.)
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  NameDescription
Explicit interface implemetationPrivate propertyICompositionElement.DisplayNameGets the display name of the directory catalog.
Explicit interface implemetationPrivate propertyICompositionElement.OriginGets the composition element from which the directory catalog originated.
Explicit interface implemetationPrivate methodIEnumerable.GetEnumeratorReturns an enumerator that iterates through the catalog. (Inherited from ComposablePartCatalog.)
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You can use a DirectoryCatalog object to parse the contents of a designated directory. Any attributed parts contained in dynamic link library (DLL) files are extracted and made available through the catalog.To restrict parsing to specific DLLs, you can specify a search pattern by using the same syntax as the Directory.GetFiles method.

Caution noteCaution

The designated directory should not allow access to non-administrators. For example, using a folder that contains temporary Internet files could create vulnerabilities in your application.

This type implements the IDisposable interface. When you have finished using the type, you should dispose of it either directly or indirectly. To dispose of the type directly, call its Dispose method in a try/catch block. To dispose of it indirectly, use a language construct such as using (in C#) or Using (in Visual Basic). For more information, see the “Using an Object that Implements IDisposable” section in the IDisposable interface topic.

The following example creates a DirectoryCatalog object that searches the directory the application runs from for parts. It uses a simple import to test the catalog. To fulfill this import, a DLL in the directory must have a matching export, as illustrated in the second code block.

public class Test2
{
    [Import]
    public Test1 data { get; set; }
}

class Program
{
    static void Main(string[] args)
    {
        DirectoryCatalog catalog = new DirectoryCatalog(".");
        CompositionContainer container = new CompositionContainer(catalog);
        Test2 test = new Test2();
        container.SatisfyImportsOnce(test);
        Console.WriteLine(test.data.data);
        Console.ReadLine();
    }
}

To create the matching export, the following code must be in a DLL file. To create a DLL file in Visual Studio, add a new project of the type "Class Library" to your solution, and place this code in it.

[Export]
public class Test1
{
    public String data = "The data!";
}

.NET Framework

Supported in: 4.5, 4

.NET Framework Client Profile

Supported in: 4

Windows 8.1, Windows Server 2012 R2, Windows 8, Windows Server 2012, Windows 7, Windows Vista SP2, Windows Server 2008 (Server Core Role not supported), Windows Server 2008 R2 (Server Core Role supported with SP1 or later; Itanium not supported)

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.
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