I’m trying to pass a COM object from C# code to Perl.

At the moment I’m wrapping my Perl code with PerlNET (PDK 9.4; ActiveState) and I have defined a simple subroutine (+ required pod declaration) in Perl to pass objects from C# to the wrapped Perl module.

It seems that the objects I pass are not recognized correctly as COM objects.

An example:

In C# (.NET 4.0), the ScriptControl is used to load a simple class from a file written in VBScript.

    var host = new ScriptControl();
    host.Language = "VBScript";
    var text = File.ReadAllText("TestScript.vbs"); 
    host.AddCode(text);

    dynamic obj = host.Run("GetTestClass");

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What I get (obj) is of type System.__ComObject. When I pass it to my Perl/PerlNET assembly and try to call method Xyz() in Perl I get the following (runtime) exception:

    Can't locate public method Xyz() for System.__ComObject

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If, however, I do more or less the same thing in Perl, it works. (In the following case, passing only the contents of my .vbs file as parameter.). I can even use the script control:

    sub UseScriptControl {
        my ($self, $text) = @_;
        my $script = Win32::OLE->new('ScriptControl');
        $script->{Language} = 'VBScript';
        $script->AddCode($text);
        my $obj = $script->Run('GetTestClass');
    
        $obj->Xyz();
    }

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Now, calling $obj->Xyz() works fine (using Win32::OLE).

In both cases I use 

    use strict;
    use Win32;
    use Win32::OLE::Variant;

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Another approach:

I can invoke methods by using InvokeMember of class System.Type if I specify *exactly* which overload I want to use and which types I’m passing:

    use PerlNET qw(typeof);

    typeof($obj)->InvokeMember("Xyz", 
        PerlNET::enum("System.Reflection.BindingFlags.InvokeMethod"), 
        PerlNET::null("System.Reflection.Binder"), 
        $obj, 
        "System.Object[]"->new());

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Using this approach would mean rewriting the whole wrapped Perl module. And using this syntax..

Now I am wondering if I am losing both the advantages of the dynamic keyword in .NET 4.0 and the dynamic characteristics of Perl (with Win32::OLE) by using PerlNET with COM objects.

It seems like my preferred solution boils down to some way of mimicking the behaviour of the dynamic keyword in C#/.NET 4.0.

Or finding some way of converting the passed COM object to something that will be recognized as compatible with Win32::OLE. Maybe extract some information of the __ComObject for it to be identified correctly as COM object.

I have to add that I posted to the PDK discussion site too (but didn’t get any response yet): http://community.activestate.com/node/18247

I would greatly appreciate any help - or advise on where to look further.

In reply to Passing COM objects from C# to Perl using PerlNET by mihe

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