I've been working with Solidworks C# API for a month. I have a solidworks document with a few patterns like Linear(LocalLPattern) and mirror(MirrorPattern) patterns. I have two applications, one for capturing features, dimensions etc., and another application (independent from the first) for selecting/modifying components that I had captured on the first application (Basically I'm capturing selection names and using selectbyid2 or swModel.Parameter in the second application).
This has been working for almost all (features/dimensions) except recently I had to capture patterns in a document in the first application and change total-instance-count/spacing of the patterns in the second application. I am able to get selection names of such pattern features by filtering with GetTypeName2 (I'm unable to obtain the SelectionType in this process, it simply gives empty string).
This link shows how to work with LinearPatternFeatureData: