使用LINQ时避免代码重复

Question

好的,我有很多方法,如下所示: - 按艺术家,专辑,年份等对列表进行排序.

        public void SortByAlbum(SortOrder sortOrder)
        {
           if (sortOrder == SortOrder.Ascending)
              _list = _list.OrderBy(x => x.Album).ToList();
           else if (sortOrder == SortOrder.Descending)
              _list = _list.OrderByDescending(x => x.Album).ToList();
        }

还有这个:

        public void SortByArtist(SortOrder sortOrder)
        {
           if (sortOrder == SortOrder.Ascending)
              _list = _list.OrderBy(x => x.Artist).ToList();
           else if (sortOrder == SortOrder.Descending)
              _list = _list.OrderByDescending(x => x.Artist).ToList();
        }

现在显然这不是好代码所以它需要重构为一个Sort()方法,但我不知道如何以最简单的方式做到这一点.我不在乎它是否使用IComparer或LINQ.

我希望它看起来像这样:

    public void Sort(SortOrder sortOrder, SortType sortType)
    {
        //implementation here
    }

    public enum SortType
    {
       Artist,
       Album,
       Year
    }

那么最简洁的方法是什么,没有代码重复？

谢谢,李

Answer 1

您应该能够模仿OrderBy扩展方法的签名:

更新1您必须在keySelector Func的第一个通用参数中显式.我打算猜你的类型并称之为"歌曲".

public void Sort<TKey>(SortOrder sortOrder,
                       Func<Song, TKey> keySelector)
{
    if (sortOrder == SortOrder.Descending)
    {
        _list = _list.OrderByDescending(keySelector).ToList(); 
    }
    else
    {
        _list = _list.OrderBy(keySelector).ToList(); 
    }
}

现在您可以像这样调用"排序":

Sort(SortOrder.Descending, x => x.Album);

更新2

跟进Tom Lokhorst的评论:如果你想预定义一些速记排序标准,你可以通过定义这样一个类来实现:

public static class SortColumn
{
    public static readonly Func<Song, string> Artist = x => x.Artist;
    public static readonly Func<Song, string> Album = x => x.Album;
}

现在你可以简单地打电话:

Sort(SortOrder.Descending, SortColumn.Artist);