DirectoryCatalog Class

A DirectoryCatalog parses the contents of the designated directory. Any attributed parts contained in DLL files are extracted and made available via the catalog. A search pattern, to restrict parsing to specific DLLs, can also be specified using the same syntax as GetFiles.

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

The following example creates a DirectoryCatalog that searches the directory the application runs from for parts. It uses a simple import to test the catalog. In order to fulfill this import, a DLL in the directory must have a matching export. (See below.)

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 separate DLL in Visual Studio, add a new project of the type "Class Library" to the solution, and put this code in it.

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

.NET Framework

.NET Framework Client Profile

Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2

Reference