意外行为:列表

我今天遇到了一个很奇怪的问题:

基本上,我想使用以下行将一种类型的数组转换为另一种类型的数组:

DirectoryInfo Source = new DirectoryInfo(@"C:\Orpheus_Music");
FileInfo[] Files = Source.GetFiles("*.mp3");

List FileList = new List();
MusicFileModel temp = new MusicFileModel();

foreach (FileInfo file in Files)
{
    temp.Name = file.Name.ToString();
    temp.Pfad = file.DirectoryName.ToString();

    FileList.Add(temp);

    Debug.WriteLine(temp.Name + ", " + temp.Pfad);
}

Debug.WriteLine("_______________");

foreach (MusicFileModel file in FileList)
{
    Debug.WriteLine(file.Name + ", " + file.Pfad);
}

但是,这不是获取Name和Pfad值的精确副本,而是输出:

01 Rolling in the Deep.mp3, C:\Orpheus_Music
02 Rumour has it.mp3, C:\Orpheus_Music
03 Turning Tables.mp3, C:\Orpheus_Music
04 Don't you remember.mp3, C:\Orpheus_Music
05 Set Fire to the Rain.mp3, C:\Orpheus_Music
06 He won't go.mp3, C:\Orpheus_Music
07 Take it all.mp3, C:\Orpheus_Music
08 I'll be waiting.mp3, C:\Orpheus_Music
09 One and only.mp3, C:\Orpheus_Music
10 Lovesong.mp3, C:\Orpheus_Music
11 Someone like you.mp3, C:\Orpheus_Music
_______________
11 Someone like you.mp3, C:\Orpheus_Music
11 Someone like you.mp3, C:\Orpheus_Music
11 Someone like you.mp3, C:\Orpheus_Music
11 Someone like you.mp3, C:\Orpheus_Music
11 Someone like you.mp3, C:\Orpheus_Music
11 Someone like you.mp3, C:\Orpheus_Music
11 Someone like you.mp3, C:\Orpheus_Music
11 Someone like you.mp3, C:\Orpheus_Music
11 Someone like you.mp3, C:\Orpheus_Music
11 Someone like you.mp3, C:\Orpheus_Music
11 Someone like you.mp3, C:\Orpheus_Music

这里出了什么问题？坦率地说这似乎是一个初学者的问题,但是,我无法找出究竟是什么导致了这一问题.

谢谢您的帮助!迈克尔赫伯特

你每次都在循环中更新同一个对象,所以你最终得到了你的对象的相同副本,List最后它只包含在最后一次迭代中设置的值,你必须在循环中实例化新对象然后将其添加到List:

foreach (FileInfo file in Files)
{
    MusicFileModel temp = new MusicFileModel(); // note this

    temp.Name = file.Name.ToString();
    temp.Pfad = file.DirectoryName.ToString();

    FileList.Add(temp);

    Debug.WriteLine(temp.Name + ", " + temp.Pfad);
}

你也可以使用Linq Select()使它更简单,但它需要更多的操作,所以对于性能来说,每个循环的简单性更好,但你也可以通过以下方式实现:

FileList = Source.GetFiles("*.mp3")
                 .Select(file => new MusicFileModel()
                     {
                        Name = file.Name.ToString(),
                        Pfad = file.DirectoryName.ToString()
                     }).ToList();