Implementing get_Item in Ruby for access in .NET


#1

Hi there.

We’re trying to access a ruby implementation of a Hash from .NET but
having trouble getting the following snip to work

require ‘Dependencies.dll’
class ParameterList
include Namespace::IParameterList

   @parameter_hash

   def initialize
           @parameter_hash = Hash.new
   end

   def []= key, value
           @parameter_hash[key] = value
   end

   def [] key
           @parameter_hash[key]
   end

   def get_Item key
           @parameter_hash[key]
   end

end

and on the .NET side:

public interface IParameterList : IEnumerable
{
int Count { get; }
IParameter this[string name] { get; }
IParameter this[int index] { get; }
IEnumerator GetEnumerator();
event ParameterValueChangedEventHandler OnParameterValueChanged;
}

When we call it from .NET with the following code (The parameters
object is an instance of the Ruby ParamterList class ):
parameter = parameters[“Key”];

The error returned is
NoMethodError: undefined method `get_Item’ for
#ParameterList:0x0000104

Is it possible to have a Ruby object with an indexer which is callable
from C#?

Thanks,
Xerx.


#2

I don’t think there’s any attempt right now to identify an indexer when
overriding virtual methods. This means that the normal Rubification
rules kick in and you get

def item key
end
def item= key, value
end

The second of these, of course, isn’t usable from within Ruby – though
I think it should still work correctly when called by C# through the
interface.

Obviously, this should be entered as a work item on Codeplex if it isn’t
there already.