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我有一个要与 OrderBy 一起使用的自定义比较器。这个比较器可以按照我想要的方式对嵌套列表进行排序。我在其他地方完美地工作,但我不能让它以我想要的方式与 Linq 一起工作。你能告诉我哪里错了吗?

编辑:我想让它工作的方式是首先按类(BaseDirectory > BaseSite > VideoEntity,总是)对我的实体进行分组,然后按字母顺序对它们进行排序(升序 = A-> Z,或降序 Z-> A)。无论如何,当我使用 SortDirectoriesDescending() 时,我会返回按升序排序的集合。默认情况下,集合以升序模式排序(因此转换器可以工作,我已经对其进行了降序测试,也可以)

public class VideoEntityComparer : IComparer<VideoEntity>
{

    int order = 1;

    public VideoEntityComparer(Boolean ascending)
    {
        if (!ascending)
        {
            this.order = -1; // so descending
        }
    }

    public VideoEntityComparer()
    {

    }

    public int Compare(VideoEntity x, VideoEntity y)
    {
        if ((x is BaseDirectory && y is BaseDirectory) || (x is BaseSite && y is BaseSite) || (x is VideoEncoder && y is VideoEncoder))
        {
            return string.Compare(x.Nom, y.Nom, false) * order; // only objects of the same type are sorted alphabetically
        }
        else if ((x is BaseDirectory && y is BaseSite) || (x is BaseSite && y is VideoEncoder))
        {
            return -1;
        }else
        {
            return 1;
        }
    }
}

private void SortDirectoriesDescending(object sender, RoutedEventArgs e)
    {
        ObservableCollection<BaseDirectory> tempDir  = new ObservableCollection<BaseDirectory>(
            Directories.OrderBy(directory => directory, new VideoEntityComparer(false)));
        Directories = tempDir;
    }
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1 回答 1

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尝试对您的比较方法进行以下更改:

public int Compare(VideoEntity x, VideoEntity y)
{
    if ((x is BaseDirectory && y is BaseDirectory) || (x is BaseSite && y is BaseSite) || (x is VideoEncoder && y is VideoEncoder))
    {
        return string.Compare(x.Nom, y.Nom, false) * order; // only objects of the same type are sorted alphabetically
    }
    else if ((x is BaseDirectory && y is BaseSite) || (x is BaseSite && y is VideoEncoder) || (x is BaseDirectory && y is VideoEncoder)) // Added (x is BaseDirectory && y is VideoEncoder)
    {
        return -1;
    }
    else
    {
        return 1;
    }
}

您的代码之前定义了 BaseDirectory < BaseSite 和 BaseSite < VideoEncoder,但 BaseDirectory > VideoEncoder 的顺序,这似乎很容易混淆,OrderBy因为您的顺序不是传递的。

于 2012-07-27T08:09:02.017 回答