在方法中将属性作为参数传递

Question

I know the title could probably be a bit more descriptive/better phrased, but it was the best I could come up with.

Currently I have a class with a lot of methods looking like the ones below:

        private static void UpdateArtists()
        {
            artists.Clear();
            foreach (AudioInfo entry in library_entries)
            {
                artists.Add(entry.Artist, entry);
            }
        }

        private static void UpdateAlbums()
        {
            albums.Clear();
            foreach (AudioInfo entry in library_entries)
            {
                albums.Add(entry.Album, entry);
            }
        }

        private static void UpdateGenres()
        {
            genres.Clear();
            foreach (AudioInfo entry in library_entries)
            {
                genres.Add(entry.Genre, entry);
            }
        }

        private static void UpdateYears()
        {
            years.Clear();
            foreach (AudioInfo entry in library_entries)
            {
                years.Add(entry.Year, entry);
            }
        }

Needless to say, writing dozens of these is very tiresome. So I was wondering if it's possible to simplify it and make a method something like this:

     private static void Update(Dictionary<string, AudioInfo> dictionary, AudioInfo.Property property)
     {
         dictionary.Clear();
         foreach (AudioInfo entry in library_entries)
         {
             dictionary.Add(entry.property, entry);
         }
         //Where "property" is a property in the AudioInfo-class.
     }

Is that doable, and if it is; how?

Thanks!

Answer 1

It seems like you have some design errors in your class if you need to do such things. nevertheless, the solution is:

private static void Update(Dictionary<string, AudioInfo> dictionary, Func<AudioInfo, string> func)
{
    dictionary.Clear();
    foreach (AudioInfo entry in library_entries)
    {
        dictionary.Add(func(entry), entry);
    }
}

And the usage is:

Update(years, x => x.Year);

Also you can use easier way, instead of call any methods you can just write:

years = library_entries.ToDictionary(x => x.Year, x => x);

If you have not any events, linked with your dictionary.

And one more thing to go - you can't add different elements with the same keys to dictionary. In your case it seems like you have different AudioInfo objects with the same Year , Genre etc.