Creating multiple instances of Imported MEF parts

Question

Currently my WPF application imports a part like this

[Import(typeof(ILedPanel)]
public ILedPanel Panel { get; set; }

But this gives ma a single intance of the class that implements ILedPanel. What I really want to do is have the ability to create as many instances that I need. Please note there is only one Export for ILedPanel included with the software at any given time.

(If I use an import with List that gives me one instance for every class implementing ILedPanel)

Any suggestions?

Answer 1

All of the other answers are pretty old, so they don't mention a relatively new feature in MEF called ExportFactory. This generic class allows you to import ExportFactory<ILedPanel> and create as many instances as you like whenever you need them, so your code would look like this:

[Import(typeof(ILedPanel)]
public ExportFactory<ILedPanel> PanelFactory { get; set; }

public ILedPanel CreateNewLedPanelInstance()
{
    return PanelFactory.CreateExport().Value;
}

This method also satisfies any imports that created part has. You can read more about using the ExportFactory class here.