Discussion:
[Python.NET] getting started - can't import a simple dll
Jason Awbrey
2010-12-15 00:53:01 UTC
Permalink
I'm evaluating PDN for use in an upcoming project.

1. installed Python 2.6.5
2. installed PDN - copied the clr.pyd file to Python's DLLs folder, and
copied Python.Runtime.dll to Python's root
3. copy my dll (VS2010, simple C# class lib with two methods) into Python's
root.
4. start python (using the python.exe from 2.6.5, not the one from PDN)
import clr
clr.AddReference("My.DLL")
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
System.IO.FileNotFoundException: Unable to find assembly
'HFF.Helper.Utilities'.

at Python.Runtime.CLRModule.AddReference(String name)
I assume I'm making some incredibly obvious newbie error. Can anyone point
me in the right direction?

And, where can I find good docs/reference/discussion on using PDN?

thanks - Jason
Laszlo Sebo
2010-12-15 01:21:32 UTC
Permalink
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Jason Awbrey
2010-12-15 01:47:29 UTC
Permalink
Thanks. I tried creating a test assembly with just a default constructor
and no other dependencies, and I get the same error when I try to import
it.

I also tried setting the path variable, through windows as well as in code,
and get the same result.

Assuming my dll is named "TestLib.dll", I should be able to do
clr.AddReference("TestLib"), correct?

Do I have to strong name my assemblies, or put them in the GAC? Or is that
optional?

Any other suggestions of how to track this down?

On Tue, Dec 14, 2010 at 7:21 PM, Laszlo Sebo <
It appears that some reference dependencies of the My.DLL assembly (the
assembly containing HFF.Helper.Utilities ?) weren't found.
Make sure that whichever referenced assembly has those classes is
accessible through the path env variables. If needed, you can add it inside
import sys
sys.path.append('place where my dlls are')
http://pythonnet.sourceforge.net/readme.html
But once you get the initial assemblies to work, its fairly straightforward
since you just use the .net classes natively from python.
cheers,
laszlo
I'm evaluating PDN for use in an upcoming project.
1. installed Python 2.6.5
2. installed PDN - copied the clr.pyd file to Python's DLLs folder, and
copied Python.Runtime.dll to Python's root
3. copy my dll (VS2010, simple C# class lib with two methods) into Python's
root.
4. start python (using the python.exe from 2.6.5, not the one from PDN)
import clr
clr.AddReference("My.DLL")
File "<stdin>", line 1, in <module>
System.IO.FileNotFoundException: Unable to find assembly
'HFF.Helper.Utilities'.
at Python.Runtime.CLRModule.AddReference(String name)
I assume I'm making some incredibly obvious newbie error. Can anyone
point me in the right direction?
And, where can I find good docs/reference/discussion on using PDN?
thanks - Jason
_________________________________________________
http://mail.python.org/mailman/listinfo/pythondotnet
Laszlo Sebo
2010-12-15 02:06:16 UTC
Permalink
When you import the assembly it will be referenced by the assembly name
defined in the project settings (which is what the dll will be named
as). GAC isn't required ( i never do that ).

I just did a quick test here. Made an empty Class project via Visual
Studio 2008.

Then tweaked the source to add 2 functions:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace ClassLibrary1
{
public class Class1
{
public string Function1()
{
return "Test Function Called";
}
public void Function2()
{
Console.WriteLine("Hello World");
}
}
}

I built it with all default settings (as a class library), then copied
the dll to the python / lib / site-packages folder, along with the
clr.pyd, Python.Runtime.dll and Python.Runtime.dll.config files

Then from python:

Python 2.5.2 (r252:60911, Feb 21 2008, 13:11:45) [MSC v.1310 32 bit (Intel
win32
Type "help", "copyright", "credits" or "license" for more information.
Post by Jason Awbrey
import clr
clr.AddReference('ClassLibrary1')
<System.Reflection.Assembly object at 0x01DF5580>
Post by Jason Awbrey
import ClassLibrary1
myObject = ClassLibrary1.Class1()
myObject.Function1()
u'Test Function Called'
Post by Jason Awbrey
myObject.Function2()
Hello World
Note that the "import ClassLibrary1" is the namespace not the assembly
(it just happens to be the same since its all default values).
I wonder if your issue is somehow related to VS2010? Could it be adding
some default references? What references are listed in VS?


cheers,
laszlo
Post by Jason Awbrey
Thanks. I tried creating a test assembly with just a default
constructor and no other dependencies, and I get the same error when I
try to import it.
I also tried setting the path variable, through windows as well as in
code, and get the same result.
Assuming my dll is named "TestLib.dll", I should be able to do
clr.AddReference("TestLib"), correct?
Do I have to strong name my assemblies, or put them in the GAC? Or is
that optional?
Any other suggestions of how to track this down?
_________________________________________________
Python.NET mailing list - PythonDotNet-+ZN9ApsXKcEdnm+***@public.gmane.org
http://mail.python.org/mailman/listinfo/pythondotnet
Jason Awbrey
2010-12-15 02:20:32 UTC
Permalink
I recompiled using .NET 2.0 and now I can load the DLL. Is there any
support for frameworks after 2.0? I'd hate to lose the ability to use LINQ.

Also, you mentioned Python.Runtime.dll.config. I don't have this file.
What's in it?

thanks for your help

On Tue, Dec 14, 2010 at 8:06 PM, Laszlo Sebo <
Post by Laszlo Sebo
When you import the assembly it will be referenced by the assembly name
defined in the project settings (which is what the dll will be named as).
GAC isn't required ( i never do that ).
I just did a quick test here. Made an empty Class project via Visual Studio
2008.
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
namespace ClassLibrary1
{
public class Class1
{
public string Function1()
{
return "Test Function Called";
}
public void Function2()
{
Console.WriteLine("Hello World");
}
}
}
I built it with all default settings (as a class library), then copied the
dll to the python / lib / site-packages folder, along with the clr.pyd,
Python.Runtime.dll and Python.Runtime.dll.config files
Python 2.5.2 (r252:60911, Feb 21 2008, 13:11:45) [MSC v.1310 32 bit (Intel
win32
Type "help", "copyright", "credits" or "license" for more information.
Post by Jason Awbrey
import clr
clr.AddReference('ClassLibrary1')
<System.Reflection.Assembly object at 0x01DF5580>
Post by Jason Awbrey
import ClassLibrary1
myObject = ClassLibrary1.Class1()
myObject.Function1()
u'Test Function Called'
Post by Jason Awbrey
myObject.Function2()
Hello World
Note that the "import ClassLibrary1" is the namespace not the assembly (it
just happens to be the same since its all default values).
I wonder if your issue is somehow related to VS2010? Could it be adding
some default references? What references are listed in VS?
cheers,
laszlo
Post by Jason Awbrey
Thanks. I tried creating a test assembly with just a default constructor
and no other dependencies, and I get the same error when I try to import it.
I also tried setting the path variable, through windows as well as in
code, and get the same result.
Assuming my dll is named "TestLib.dll", I should be able to do
clr.AddReference("TestLib"), correct?
Do I have to strong name my assemblies, or put them in the GAC? Or is
that optional?
Any other suggestions of how to track this down?
_________________________________________________
http://mail.python.org/mailman/listinfo/pythondotnet
Laszlo Sebo
2010-12-15 04:25:14 UTC
Permalink
Yeah you don't actually need the .config file, it's just a dll mapping file for use with mono on linux (i've been in linux land for a while, so it must have popped from my subconcious).

I believe currently clr 2.x is supported, which means that up to .net 3.5 it should work fine, as those releases still use the 2.0 runtime (someone correct me if i'm wrong). LINQ was added with 3.5, so it should work.


cheers,
laszlo

I recompiled using .NET 2.0 and now I can load the DLL. Is there any support for frameworks after 2.0? I'd hate to lose the ability to use LINQ.

Also, you mentioned Python.Runtime.dll.config. I don't have this file. What's in it?
Dave Hirschfeld
2010-12-15 10:09:32 UTC
Permalink
 
I believe currently clr 2.x is supported,
which means that up to .net 3.5 it should work fine, as those releases
still use the 2.0 runtime (someone correct me if i'm wrong). LINQ was added
with 3.5, so it should work.
 
cheers,
laszlo
 
I
recompiled using .NET 2.0 and now I can load the DLL.  Is there any
support for frameworks after 2.0?  I'd hate to lose the ability to use
LINQ.Also, you mentioned Python.Runtime.dll.config.  I don't have
this file.  What's in it?
I managed to compile Python.NET for .NET 4 with only a couple of minor
modifications to the code:

http://thread.gmane.org/gmane.comp.python.dotnet/969

NB: I put both clr.pyd and Python.Runtime.dll in my python root dir (C:\Python26)

HTH,
Dave

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David Shi
2010-12-22 23:38:13 UTC
Permalink
I am trying to raise finance to setup and develop a multi-lingual pythondotnet
site to promote Pythondotnet globally in London.

Pythondotnet is hardly known, taught, used in this part of the world.
Certainly, it is true in China.

To start with, I would like get a team going to do a English and Chinese site.

Can anyone suggest the way forward? I am sure that I will need financial
support to start with.

Regards.

David Shi

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