This is the code I use all the time to append a dir to the system path and then load assemblies from that dir. (note, they’re not in the GAC {woot!})


if os.path.isfile(myFile):

    if not myDir in sys.path:

        sys.path.insert(0, myDir)



myFile is the name of the assembly dll ala: “C:/testdir/myAssembly.dll”

myDir would be: “C:/testdir”


I always make sure that the namespace in the compiled assembly is the same as the filename. This seems to make things run more smoothly.


From: [] On Behalf Of Sharon Rozenblum
Sent: Wednesday, February 23, 2011 5:37 AM
To: Oleksii Bidiuk
Subject: Re: [Python.NET] Setting PYTHONPATH from code




Trying to do as you said:


            string script = "import sys\nsys.path.insert(0, '" + modulePath + "')";
            IntPtr pythonLock = PythonEngine.AcquireLock();


And then:

            IntPtr gs = PythonEngine.AcquireLock();
            pyportal = PythonEngine.ImportModule(moduleName);
            if (pyportal == null)





I got Null value from the ImportModule.


When setting the PYTHONPATH manually in the system variables with the “modulePath” and opening the VS is works.


Any idea? 







From: Oleksii Bidiuk []
Sent: Thursday, February 10, 2011 2:21 PM
To: Sharon Rozenblum
Subject: Re: [Python.NET] Setting PYTHONPATH from code


Hi Sharon,


What do you want to achieve with this? If you want to provide path for loading your own modules you can change the sys.path value by e.g. running a 'initialization' script with 


import sys

sys.path.insert(0, 'your/own/path')


You can build up the script above in C# by inserting the path you need and then performing e.g. RunSimpleString(<script>) like


string script = "import sys\nsys.path.insert(0, '" + <variable_with_path> + "')");

IntPtr pythonLock = AcquireLock();



Does this help?


2011/2/10 Sharon Rozenblum <>



Can someone tell me how to set PYTHONPATH variable in code when working with Python.Runtime.dll without changing the value in the system variables before.







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