[Qgis-developer] Problem using vector data provider in python

[Chris Crook]

Thanks Martin

Good point .. There really isn't any reason not to create a QgsVectorLayer.  I was failing to distinguish between map layers that are displayed, and QgsVectorLayer, which isn't

Many thanks
Chris

-----Original Message-----
From: Martin Dobias [mailto:wonder.sk at gmail.com] 
Sent: Wednesday, 15 December 2010 9:49 a.m.
To: Chris Crook
Cc: qgis-developer at lists.osgeo.org
Subject: Re: [Qgis-developer] Problem using vector data provider in python

On Tue, Dec 14, 2010 at 9:18 PM, Chris Crook <ccrook at linz.govt.nz> wrote:
> Hi All
>
> I'm wondering if it is possible to use a QgsVectorDataProvider independently from a map layer in Python.  For example, I'd like to open a GML file and read features, etc from it without creating a map layer.
>
> I can get as far as
>
> p=QgsProviderRegistry.instance().getProvider("ogr","myfile.gml")
>
> But what I get back is QgsDataProvider.
>
> <qgis.core.QgsDataProvider object at 0x099BE6F0>
>
> So all the QgsVectorDataProvider methods don't seem to be available.

Hi Chris

there was a missing conversion routine that would tell python that a subclass exists. I've added it to trunk in r14911, so now you should get QgsVectorDataProvider instance.

While instantiating a vector data provider without its QgsVectorLayer counterpart is possible, IMO it's more convenient to use the latter (and there's barely any overhead).

Regards
Martin
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