[IronPython] Loading IronPython.dll from memory

Jeff Slutter jslutter at reactorzero.com
Wed Dec 17 21:19:41 CET 2008

[I can work around this, but I'm curious if there is a solution]

Due to some crazy requirements, I'm trying to load my assemblies from
memory. I have setup an Assembly Resolver with:

AppDomain.CurrentDomain.AssemblyResolve += new

And it gets called. Inside the ResolveInternalAssembly I do the following:

1) check my Dictionary to see if I have already loaded the assembly, if
so I return it, otherwise...
2) I, currently, open the file, read in the file to byte[] and then call
3) AppDomain.CurrentDomain.Load(asmbytes) to load the Assembly, store it
to the dictionary and return it.

(see: http://weblogs.asp.net/justin_rogers/archive/2004/06/07/149964.aspx)

This works well and all until I get to the following code within one of
my loaded assemblies:
m_engine = m_runtime.GetEngine("Python");

It throws an exception saying:
Type 'IronPython.Runtime.PythonContext' doesn't provide a suitable
public constructor or its implementation is faulty: The type initializer
for 'IronPython.Runtime.SysModule' threw an exception.

I assume this is some sort of security/permissions problem because that
is the main thing that is different when loading an assembly from memory
than file.

My work around is to pre-load the IronPython.dll assembly before hooking
up my AssemblyResolve (its the only one I have to 'preload')
dynamicAssemblyHash["IronPython"] =

Any ideas?

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