[IronPython] Viewlets: Any F# experts here?

Michael Foord fuzzyman at voidspace.org.uk
Thu Jun 26 23:58:55 CEST 2008

The viewlets that come with VSLab look *really* cool. They're based on 
F# so I decided to see if they could be used from IronPython.


The dependencies are pretty hefty. You need F# installed *and* Managed 
DirectX (June 2008 SDK ~450mb seems to fulfil the dependency).

To get at the viewlet assemblies you need Visual Studio Pro installed as 
well, but they can be extracted from the VSLabs msi installer without VS 

Ok, so with all the dependencies installed I attempt to use them - and 
*boom*. Anyone here got any ideas?

IronPython 2.0 Beta ( on .NET 2.0.50727.1434
Copyright (c) Microsoft Corporation. All rights reserved.
 >>> import clr
 >>> clr.AddReference('vslabfsicore')
 >>> clr.AddReference('vslabviewlets')
 >>> clr.AddReference('vslabcore')
 >>> from GraphViewlet import GraphControl
 >>> g = GraphControl()
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "vslabviewlets", line unknown, in .ctor
  File "vslabfsicore", line unknown, in .ctor
  File "System.Windows.Forms", line unknown, in get_Controls
  File "System.Windows.Forms", line unknown, in get_Properties
SystemError: Object reference not set to an instance of an object.

Interesting that the explosion is inside winforms. Referencing that 
assembly first makes knows difference.

Michael Foord


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