using registered com object dll from .NET

Question

Hi all,

I implemented a python com server and generate an executable and dll using py2exe tool. then I used regsvr32.exe to register the dll.I got a message that the registration was successful. Then I tried to add reference to that dll in .NET. I browsed to the dll location and select it, but I got an error message box that says: A reference to the dll could not be added, please make sure that the file is accessible and that it is a valid assembly or COM component.The code of the server and setup script is added below. I want to mention that I can run the server as a python script and consume it from .net using late binding. Is there something I'm missing or doing wrong? I would appreciate any help.

thanks, Sarah

hello.py

import pythoncom

import sys

class HelloWorld:

#pythoncom.frozen = 1
if hasattr(sys, 'importers'):
    _reg_class_spec_ = "__main__.HelloWorld" 
_reg_clsctx_ = pythoncom.CLSCTX_LOCAL_SERVER
_reg_clsid_ = pythoncom.CreateGuid()
_reg_desc_ = "Python Test COM Server"
_reg_progid_ = "Python.TestServer"
_public_methods_ = ['Hello']
_public_attrs_ = ['softspace', 'noCalls']
_readonly_attrs_ = ['noCalls']

def __init__(self):
    self.softspace = 1
    self.noCalls = 0

def Hello(self, who):
    self.noCalls = self.noCalls + 1
    # insert "softspace" number of spaces
    print "Hello" + " " * self.softspace + str(who)
    return "Hello" + " " * self.softspace + str(who)

if name=='main': import sys if hasattr(sys, 'importers'):

    # running as packed executable.

    if '--register' in sys.argv[1:] or '--unregister' in sys.argv[1:]:

        # --register and --unregister work as usual
        import win32com.server.register
        win32com.server.register.UseCommandLine(HelloWorld)
    else:

        # start the server.
        from win32com.server import localserver
        localserver.main()
else:

    import win32com.server.register
    win32com.server.register.UseCommandLine(HelloWorld)

setup.py

from distutils.core import setup import py2exe

setup(com_server = ["hello"])

Answer 1

If you want to use a registered Com object, you need to find it on the Com tab in the Add Reference dialog box. You do not navigate to the dll.

Answer 2

The line:

_reg_clsid_ = pythoncom.CreateGuid()

creates a new GUID everytime this file is called. You can create a GUID on the command line:

C:\>python -c "import pythoncom; print pythoncom.CreateGuid()"
{C86B66C2-408E-46EA-845E-71626F94D965}

and then change your line:

_reg_clsid_ = "{C86B66C2-408E-46EA-845E-71626F94D965}"

After making this change, I was able to run your code and test it with the following VBScript:

Set obj = CreateObject("Python.TestServer")   
MsgBox obj.Hello("foo")

I don't have MSVC handy to see if this fixes the "add reference" problem.

Answer 3

I will answer my question to help any one may have similar questions. I hope that would help. I can not find my server on the COM tab because, .NET (& Visual-Studio) need COM servers with TLB. But Python's COM servers have no TLB. So to use the server from .NET by (C# and Late binding). The following code shows how to make this:

// the C# code

using System;

using System.Collections.Generic;

using System.Linq;

using System.Text;

using System.Reflection;

namespace ConsoleApplication2

{

class Program

{
    static void Main(string[] args)

    {

          Type pythonServer;
          object pythonObject;
          pythonServer = Type.GetTypeFromProgID("PythonDemos.Utilities");
          pythonObject = Activator.CreateInstance(pythonServer);

    }
}

} `