Return a Perl object from a different Perl class to C# using PerlNET

Question

I have two Perl modules which I want to expose as object types to C#. One of them constructs objects of the other type and returns it using a method as shown below. I'm including a reference to Type2.dll in Type1.dll, and referencing them both in C#. As the code shows I can construct a Type2 object directly from C#, but I can't return a Type2 object that was constructed by a method in Type1. Any ideas?

(This is cross-posted from http://community.activestate.com/forum/return-perl-object-different-perl-class-c.)

C#:

Type1 obj1 = new Type1(); // Works
Type2 test = new Type2(); // Works
Type2 obj2 = obj1.make2(); 
// Fails: System.InvalidCastException: Unable to cast object of type 
// 'PerlRunTime.SV' to type 'Type2' at Type1.make2()

Perl: Type1.pm

package Type1;

use strict;
use Type2;

=for interface
    [interface: pure]
    static Type1();
    Type2 make2();
=cut

sub new {
    my $class = shift;
    return bless {}, $class;
}

sub make2 {
    my $this = shift;
    return Type2->new();
}

1;

Perl: Type2.pm

package Type2;

use strict;

=for interface
    [interface: pure]
    static Type2();
=cut

sub new {
    my $class = shift;
    return bless {}, $class;
}

1;

Answer 1

Since this was cross-posted to community.activestate.com and has been answered there, I'll copy the answer from there to here, but I'll trim it down because I think it's too lengthy.

The main problem is that the way you wrote it, Type2 is not considered a type, and calling Type2->new() does not translate to a constructor call (but a static method invocation).

The following changes to your code fix this:

• In Type2.pm, change package Type2 to package Sample::Type2. This makes Type2 a type and Sample a namespace.
• In Type1.pm, similarly change package Type1 to package Sample::Type1.
• In Type1.pm, change use Type2; to use namespace "Sample";. This imports Type2 as a type.

The posted C# code works as required after these changes.