Calling a .Net function in Python which has a reference parameter

Question

I'm using IronPython in VS2012 and trying to call a .Net function which takes in a Ref parameter,

Lib.dll

public int GetValue(ref double value)
{
  ...
}

Python:

import clr
clr.AddReference('Lib.dll')
from LibDll import *

value =0.0
x = GetValue(value)

am I missing something, in C# we use ref along with the variable name, what about here in Python?

Answer 1

There are two ways you can invoke methods with out or ref parameters from IronPython.

In the first case the call is handled by automatic marshalling. The return value and changed refs are wrapped in a tuple and (while having 15.1 as an example double to be passed) can be used like:

(returned, referenced) = GetValue(15.1)

The more explicit way is providing a prepared clr-reference:

refParam = clr.Reference[System.Double](15.1)
result = GetValue(refParam)