WPF run code programmatically when a DLL is loaded at runtime

Question

I am modifying my wpf application in order to execute part of codes only when a DLL is loaded at runtime. I'm using this kind of pattern:;

public List<T> LoadDLL<T>(string path, string pattern)
    where T : new()
{
    return Directory.GetFiles(Path.GetFullPath(path), pattern)
        .SelectMany(f => Assembly.LoadFile(f).GetTypes()
            .Where(t => !t.IsAbstract && typeof(T).IsAssignableFrom(t))
            .Select(t => (T)Activator.CreateInstance(t)))
        .ToList();
}

Which is the best way to condition the main app code in order to, for example, run a method only if a particular DLL is loaded?