[python-win32] COM Automation: Problem Accessing Property of Object

[Tim Roberts]

Emre CETIN via python-win32 wrote:
> Hi, I've been looking for a solution to this question for some time
> now. Hopefully you could help me out. There's a program (Golden
> Software Surfer) that I have successfully automated using Python COM.
> I normally am able to control every portion I need. The part I have
> trouble accessing is under its "Property Manager". Even though I am
> using the description provided in the software's documents & help
> files I get an error saying:
>
> AttributeError: '<win32com.gen_py.Surfer 13 Type Library.IShape
> instance at 0x2327715907232>' object has no attribute 'ShowColorScale'
>
> "ShowColorScale" is just an example of one property/method in the
> Property Manager window.
>
> Here is the example code I have been working with:
> |importwin32com.client srf
> =win32com.client.gencache.EnsureDispatch('Surfer.Application')Plot=srf.Documents.Add(1)srf.Visible=TrueMapFrame1=Plot.Shapes.AddImageMap(GridFileName="C:/test.grd")ImageLayer1=MapFrame1.Overlays(1)ImageLayer1.ShowColorScale=True#
> this is where i get the error|

The problem here, I think, is that ShowColorScale is a property of the
IContourMap interface, but you've been given an IShape interface.  One
of the issues about COM is that some objects implement many different
interfaces, and you have to know which interface to ask for to get the
methods and properties you want.

The answer, as the old poster suggested, is to query the IShape object
for its IContourMap interface.  It shouldn't be very much more
complicated than this:

    ImageMap1 = ImageLayer1.CastTo( "IContourMap" )
    ImageMap1.ShowColorScale = True

-- 
Tim Roberts, timr at probo.com
Providenza & Boekelheide, Inc.