Question

我有一个列表：

List<Song> SongList = new List<Song>();

由一群人填充：

SongList.Add(new Song(songID, "Dirt", "Alice in Chains", "Rooster", "Rock", "02:32"));

歌曲的详细信息通过以下方式填充到ListBox中：

private void songTitle_TextChanged(object sender, EventArgs e)
{
    i = 0;

    for (; i < songTitle.Text.Length; i++)
    {
        songResultBox.Items.Clear();
        var songResult = from song in SongList
        where song.SongTitle != null && song.SongTitle.Length >= songTitle.Text.Length
            && songTitle.Text == song.SongTitle.Substring(0, i+1)
        select new { sId = song.SongID, album = song.SongAlbum, artist = song.SongArtist, title = song.SongTitle, 
            genre = song.SongGenre, length = song.SongLength };

        foreach (var item in songResult)
        {
            songResultBox.Items.Add(new Song(item.sId, item.album, item.artist, item.title, item.genre, item.length));
                songResultBox.DisplayMember = "FullName";
                songResultBox.ValueMember = "songID";
        }
    }
}

问题是：我如何创建一个按钮（或实际上是4个）来获取ListBox的'songResultBox'的内容，并按照标题，专辑，艺术家，流派等对其内容进行排序。

Answer 1

创建按钮，根据要排序的属性对其进行标记，向按钮添加单击事件，对项目进行排序（希望您保留了它们的列表），然后重新填充列表框：

private bool descendingSongTitleSort = false;
private bool descendingArtistSort = false;

// Artist button clicked event
private void artistButtonClicked(object sender, EventArgs args)
{
    Func<Song, IComparable> sortProp = (song => song.Artist);
    sortListBox(songResultBox, descendingArtistSort, sortProp);
    descendingSongTitleSort = false;
    descendingArtistSort = !descendingArtistSort;
}

// Title button clicked event
private void titleButtonClicked(object sender, EventArgs args)
{
    Func<Song, IComparable> sortProp = (song => song.Title);
    sortListBox(songResultBox, descendingSongTitleSort, sortProp);
    descendingSongTitleSort = !descendingSongTitleSort;
    descendingArtistSort = false;
}

// Sorting function
private void sortListBox(
    ListBox box, 
    bool descending, 
    Func<Song, IComparable> sortProperty)
{
    List<Song> items = new List<Song>();
    foreach (Object o in box.Items)
    {
        Song s = o as Song;
        items.Add(s);
    }
    box.Items.Clear();
    if(descending)
    {
        items = items.OrderByDescending(sortProperty).ToList(); 
    } 
    else 
    {
        items = items.OrderBy(sortProperty).ToList();
    }
    foreach(Song s in items)
    {
        box.Items.Add(s); 
    }
}

如果您不想担心向相反方向求助，则不需要降序布尔。

按属性对对象的ListBox进行排序

1 个答案: