0

我有一个简单的 (ASP.NET) 网页，它列出了文件夹中特定类型的文件并将它们呈现在 ListView 中。

我尝试按 LastWriteTime 降序对它们进行排序，也就是说，以相反的日期顺序。然而，虽然排序过程确实改变了数组的顺序，但它并没有正确排序。例如，LastWriteTime 为的一项#6/3/2011 12:00:00位于列表顶部，但 LastWriteTime 为的另一项#12/16/2011 12:00:00在排序后位于列表的中间。

任何想法为什么？

代码：

        Dim dirInfo As New DirectoryInfo(Server.MapPath(AppSettings.Item("ContentDir")))
        Dim FileArrayList As New ArrayList(dirInfo.GetFiles("*.msg", SearchOption.TopDirectoryOnly))

        Dim SortDirections As New Dictionary(Of String, SqlClient.SortOrder)

        With FileArrayList
            .TrimToSize()
            .Sort(New FileInfoComparer(SqlClient.SortOrder.Descending, "LastWriteTime"))
        End With

FileInforComparer 类：

Imports System.IO
Imports System.Reflection


Public Class FileInfoComparer
    Implements IComparer

    Private _sortOrder As System.Data.SqlClient.SortOrder
    Private _sortColumn As String

    ''' <summary>
    ''' Constructs new Comparer object, using the supplied SortOrder and SortColumn parameters
    ''' </summary>
    ''' <param name="sortOrder">Defines the SortOrder for the comparison</param>
    ''' <param name="sortColumn">Defines which column is sorted</param>
    ''' <remarks></remarks>
    Public Sub New(ByVal sortOrder As System.Data.SqlClient.SortOrder, ByVal sortColumn As String)
        _sortOrder = sortOrder
        _sortColumn = sortColumn
    End Sub


    ''' <summary>
    ''' Defines the Sorting mechanism for FileInfo objects
    ''' </summary>
    ''' <param name="x">First FileInfo object to compare</param>
    ''' <param name="y">Second FileInfo object to compare</param>
    ''' <returns></returns>
    ''' <remarks></remarks>
    Public Overridable Overloads Function Compare(ByVal x As Object, ByVal y As Object) As Integer Implements System.Collections.IComparer.Compare

        Dim oX_PI As PropertyInfo = CType(x, FileInfo).GetType.GetProperty(_sortColumn)
        Dim oY_PI As PropertyInfo = CType(y, FileInfo).GetType.GetProperty(_sortColumn)
        Dim Result As Int16 = oX_PI.GetValue(x, Nothing).CompareTo(oY_PI.GetValue(x, Nothing))

        'If DESC then reverse the result
        If _sortOrder = SqlClient.SortOrder.Descending Then Result = Result * -1

        Return Result

    End Function
End Class
4

2 回答 2

3

LastWriteTime 可以作为字符串返回，它解释了排序顺序。这些值被排序为字符串，而不是 DateTime 对象。将字符串解析为日期时间，排序顺序应该是正确的。

于 2011-12-22T14:48:52.870 回答
1

这是一个使用 LINQ 的解决方案。这是用 C# 编写并转换为 VB 的，所以希望这可行。

Dim dirInfo = New DirectoryInfo(Server.MapPath(AppSettings.Item("ContentDir")))
Dim fileList = dirInfo.GetFiles("*.msg", SearchOption.TopDirectoryOnly).OrderByDescending(Function(f) f.LastWriteTime)

的类型fileList将是IEnumerable<FileInfo>。如果您需要它是一个可变列表，而不是使用 an ArrayList，我建议使用 a List<FileInfo>，这可以通过添加.ToList()到然后结束来完成，就像这样

Dim fileList = dirInfo.GetFiles("*.msg", SearchOption.TopDirectoryOnly).OrderByDescending(Function(f) f.LastWriteTime).ToList()
于 2011-12-23T13:46:19.933 回答