Import multiple instances of a class differed by parameter value in MEF

Question

I would like to export from one type two its different instances that differ in parameters that were passed to their constructors.

To be more specific:

interface IA {
 string P { get; }
}

[Export(typeof(IA))]
[ExportMetadata("p", "1")]
[ExportMetadata("p", "2")]
class A : IA {

 [ImportingConstructor]
 public A( string p ) {
  this.P = p;
 }

 public string P { get; set; }
}

I would like, when importing a collection of IA's, get two instances of A that were instantiated with different values of constructor parameter p - one with 1 and other with 2 (I want these parameters to be taken from export metadata).

Is it possible to archieve this in MEF?

Answer 1

Would a property export work for your scenario?

class A : IA
{
    public A(string p) { P = p; }
    public string P { get; set; }
}

class AExports
{
    [Export(typeof(IA))]
    [ExportMetadata("p", "1")]
    public IA A1
    {
        get { return new A("1"); }
    }

    [Export(typeof(IA))]
    [ExportMetadata("p", "2")]
    public IA A2
    {
        get { return new A("2"); }
    }
}