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Discussion on: What You Need To Know About The Helpful Strategy Pattern

risingsungames profile image
James • Edited

Nice article.

Apologies if this is obvious, but I like to use reflection to find classes implementing ITextExtractor followed by Activator.CreateInstance to instantiate them and add them to the array at runtime, thereby reducing the steps needed in adding a new implementation to just step 1 in your list above - "Add the new text extraction class".

Of course, this is only useful if the order of the items in the array isn't important!

kylegalbraith profile image
Kyle Galbraith Author

James that is a slick idea. I would like to see a demo of that with some code so that I can wrap my head around it further. Thank you for the comments.

risingsungames profile image

Sure! Might not be suitable for a group project, it makes assumptions that all ITextExtractor classes have parameterless constructors which isn't immediately obvious and wouldn't go down well in my employers code reviews, but for personal projects I find it useful! Something along the lines of this:

private ITextExtractor[] _extractors;

public RunExtraction()
    _extractors =  AppDomain.CurrentDomain.GetAssemblies()
        .SelectMany(x => x.GetTypes())
        .Where(t => typeof(ITextExtractor).IsAssignableFrom(t) && !t.IsInterface)
        .Select(t => (ITextExtractor)Activator.CreateInstance(t))