[IronPython] how to convert C# MarshalAs code to IronPython

[Ashley Abraham]

Hi,
    I have the following C# code and I am trying to do the same
functionality in IronPython, any help is appreciated.

I was trying to do the same functionality in IronPython using the clrtype.py
from the IronPython-2.6-Samples and I am able to connect to the library and
the function but I am having trouble passing array of strings. With the
current code it only passes the first letter and then it crashes.

I am trying to call  cwavec(int, int, char *) and it is a C function which
is part of the vniwave.dll and I am trying access it in IronPython.

C# code:

namespace PVWave
{
    public class OPI
    {
        [DllImport("C:\\datk_code\\VNI\\wave\\bin\\bin.i386nt\\vniwave.dll",
            EntryPoint = "cwavec",
            ExactSpelling = false,
            CharSet = CharSet.Ansi,
            SetLastError = true)]
        public static extern unsafe int cwavec(Int32 action, Int32 nCmds,
            [MarshalAs(UnmanagedType.LPArray, ArraySubType =
UnmanagedType.LPStr, SizeParamIndex = 10)] string[] cmds);

    }
}

Here is my attempt in IronPython:

import clrtype
import System
import sys

class OPI(object):
    "Description of Class"

    # Note that you could also the "ctypes" modules instead of pinvoke
declarations
    __metaclass__ = clrtype.ClrClass

    sys.path.append("C:\\datk_code\\VNI\\wave\\bin\\bin.i386nt")

    from System.Runtime.InteropServices import DllImportAttribute,
PreserveSigAttribute
    DllImport = clrtype.attribute(DllImportAttribute)
    PreserveSig = clrtype.attribute(PreserveSigAttribute)


    @staticmethod
    @DllImport("vniwave.dll")
    @PreserveSig()
    @clrtype.accepts(System.Int32, System.Int32,
System.Array[System.String])
    @clrtype.returns()
    def cwavec(action, nCommands, commands): raise RuntimeError("this should
not get called")

def call_pinvoke_method_pvwave():
    print "Calling pinvoke pvwave methods:"
    actionNum = 2
    nCommands = 1
    commands = System.Array[System.String](['PRINT, "Connected to PV-Wave
from IronPython"'])
    print "cwavec(action, nCommands, commands):"
    OPI.cwavec(actionNum, nCommands, commands)

call_pinvoke_method_pvwave()

Thanks
Ash
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