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I am using this code to get the symbol associated with a feature:

IFeature feature = geoFeatureLayer.FeatureClass.GetFeature( geoFeatureLayer.FeatureClass.FeatureClassID );
geoFeatureLayer.Renderer.get_SymbolByFeature( feature );

Of course, now I have encountered a layer where "FeatureClassID = -1" and this code crashes with "ROW_NOT_FOUND." The help says: "...IFeatureClass::FeatureClassID will always return -1 for Coverage and Shapefile feature classes." I (sort of) understand that but how should I get the Symbol for that kind of feature? Suggestions?

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1 Answer

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You should pass an objectID to IFeatureClass.GetFeature, not a ClassID.

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Where do I get the ObjectId? The help says, "Since IFeatureClass inherits from IObjectClass, you can also get the feature class ID from IObjectClass:: ObjectClassID." But that is -1 also. – Chaz Feb 8 '12 at 19:56
A featureclass contains a collection of features. When you draw a map the map calls ILayer.Draw. For a featurelayer it will loop through each feature in the featureclass and for each feature get its symbol and draw it. You can use a FeatureCursor to get features. – Kirk Kuykendall Feb 8 '12 at 20:07
Aaaah! Doh! I need a feature so I grab the first one that a featureCursor returns and that works! Thanks. – Chaz Feb 8 '12 at 22:07
don't forget to call ReleaseComObject on the cursor when done with it. – Kirk Kuykendall Feb 8 '12 at 22:59

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