topic How do I determine the type of data referenced in a layer file? in ArcObjects SDK Questions

How do I determine the type of data referenced in a layer file?

DennisGeasan — Tue, 05 Oct 2010 22:46:58 GMT

I want to determine the type of data that is referenced in a layer file. For example, I open a layer file that is referencing a raster dataset. In code how do you determine that the layer file is referencing a raster dataset? Right now I first use a 'try' block and QI to the IFeatureLayer interface. If this fails then in the 'catch' block I QI to IRasterLayer. I would rather first determine that the layer is pointing to a raster dataset and then use a 'switch/case' block to work with the appropriate interface.

My current method:

string LayerFileLocation = "C:\SomeLayerFile.lyr";
ILayerFile layerFile = new ESRI.ArcGIS.Carto.LayerFileClass();
layerFile.Open(LayerFileLocation);
ILayer pLayer = layerFile.Layer;
IFeatureLayer2 pFeatureLayer2;
IRasterLayer pRasterLayer;
try
{
pFeatureLayer2 = (IFeatureLayer2)pLayer;
}
catch
{
pRasterLayer = (IRasterLayer)pLayer;
}

Dennis Geasan
GIS Technolgies

Re: How do I determine the type of data referenced in a layer file?

NeilClemmons — Wed, 06 Oct 2010 13:23:19 GMT

You just need to check the type using Is in C#:

If (layer Is IFeatureLayer)
{
// do something
}
ElseIf (layer Is IRasterLayer)
{
// do something
}

It would be nice if you could use a Switch block to do this instead of a bunch of Else/ElseIfs but I don't think you can do that.

Re: How do I determine the type of data referenced in a layer file?

DennisGeasan — Tue, 12 Oct 2010 22:38:18 GMT

So that's what Is is! Thanks Neil.