如何在Visual Basic中对List(Of Class)类型的对象列表进行冒泡排序？

需求说明 #

需要基于冒泡排序逻辑，实现对List(Of Exercises)对象列表的排序，支持按指定字段升序（ASC）或降序（DESC）排列。已定义Exercises类并声明对象列表，现有排序代码未完成，需补充完整实现。

现有代码 #

对象列表声明 #

Dim Exercises As New List(Of Exercises)

Exercises类定义 #

Public Class Exercises
    'properties
    Private _Name As String
    Private _Position As String
    Private _Equipment As String
    Private _bodyPart As String
    Private _beginnerStandard As Integer
    Private _noviceStandard As Integer
    Private _intermediateStandard As Integer
    Private _advancedStandard As Integer
    Private _eliteStandard As Integer

    Public Sub New() 'default constructor
        Name = ""
        Position = ""
        Equipment = ""
        bodyPart = ""
        beginnerStandard = 0
        noviceStandard = 0
        intermediateStandard = 0
        advancedStandard = 0
        eliteStandard = 0 '修正原代码重复赋值advancedStandard的错误
    End Sub
    Public Sub New(ByVal Name As String, ByVal Position As String, ByVal Equipment As String, ByVal bodypart As String, ByVal beginnerStandard As Integer,
                         ByVal noviceStandard As Integer, ByVal intermediateStandard As Integer, ByVal advancedStandard As Integer, ByVal eliteStandard As Integer)
        'overloaded constructor
        _Name = Name
        _Position = Position
        _Equipment = Equipment
        _bodyPart = bodypart
        _beginnerStandard = beginnerStandard
        _noviceStandard = noviceStandard
        _intermediateStandard = intermediateStandard
        _advancedStandard = advancedStandard
        _eliteStandard = eliteStandard
    End Sub
    'getters and setters for the properties
    Public Property Name As String
        Get
            Return _Name
        End Get
        Set(ByVal value As String)
            _Name = value
        End Set
    End Property
    Public Property Position As String
        Get
            Return _Position
        End Get
        Set(ByVal value As String)
            _Position = value
        End Set
    End Property
    Public Property Equipment As String
        Get
            Return _Equipment
        End Get
        Set(ByVal value As String)
            _Equipment = value
        End Set
    End Property
    Public Property bodyPart As String
        Get
            Return _bodyPart
        End Get
        Set(ByVal value As String)
            _bodyPart = value
        End Set
    End Property
    Public Property beginnerStandard As Integer
        Get
            Return _beginnerStandard
        End Get
        Set(ByVal value As Integer)
            _beginnerStandard = value
        End Set
    End Property
    Public Property noviceStandard As Integer
        Get
            Return _noviceStandard
        End Get
        Set(ByVal value As Integer)
            _noviceStandard = value
        End Set
    End Property
    Public Property intermediateStandard As Integer
        Get
            Return _intermediateStandard
        End Get
        Set(ByVal value As Integer)
            _intermediateStandard = value
        End Set
    End Property
    Public Property advancedStandard As Integer
        Get
            Return _advancedStandard
        End Get
        Set(ByVal value As Integer)
            _advancedStandard = value
        End Set
    End Property
    Public Property eliteStandard As Integer
        Get
            Return _eliteStandard
        End Get
        Set(ByVal value As Integer)
            _eliteStandard = value
        End Set
    End Property
End Class

未完成的排序代码 #

Sub bubbleSort(ByVal OrderAscDesc, ByVal orderColumn)
        Dim tempHolder As Exercises
        Dim outer As Integer = getArrayOfObjectsLength()
        Dim noSwap As Boolean = True

        If OrderAscDesc = "ASC" Then
            While Not (outer = -1) Or noSwap = False
                noSwap = True
                For Each obj In Exercises
                    If obj.

                    End If
            Next
            End While
        ElseIf OrderAscDesc = "DESC" Then

        End If
    End Sub
'原函数存在逻辑错误，无法正确获取列表长度
    Function getArrayOfObjectsLength()
        Dim elements = 0
        For Each obj In Exercises
            elements += Exercises.Name.Length
        Next
        Dim newArray(elements - 1) As Integer
        Dim index = 0
        For Each obj In Exercises
            Dim n = Exercises.Result.Length
            Array.Copy(Exercises.Result, 0, newArray, index, n)
            index += n
        Next
        Console.WriteLine($"The new array has {newArray.Length} elements.")
    End Function

完整实现方案 #

修正后的排序代码 #

'按指定字段和顺序冒泡排序List(Of Exercises)
Sub bubbleSort(ByVal OrderAscDesc As String, ByVal orderColumn As String)
    Dim tempHolder As Exercises
    Dim listCount As Integer = Exercises.Count
    Dim noSwap As Boolean

    '冒泡排序核心逻辑
    For outer As Integer = listCount - 1 To 1 Step -1
        noSwap = True
        For inner As Integer = 0 To outer - 1
            '根据排序字段和顺序判断是否需要交换
            If NeedSwap(Exercises(inner), Exercises(inner + 1), orderColumn, OrderAscDesc) Then
                '交换两个对象
                tempHolder = Exercises(inner)
                Exercises(inner) = Exercises(inner + 1)
                Exercises(inner + 1) = tempHolder
                noSwap = False
            End If
        Next
        '如果本轮无交换，说明列表已排序，提前退出
        If noSwap Then Exit For
    Next
End Sub

'判断两个Exercises对象是否需要交换的辅助函数
Private Function NeedSwap(ByVal obj1 As Exercises, ByVal obj2 As Exercises, ByVal column As String, ByVal sortOrder As String) As Boolean
    Select Case column.ToLower()
        Case "name", "position", "equipment", "bodypart"
            '字符串类型字段比较，使用文本比较（忽略大小写）
            Dim compareResult As Integer = String.Compare(obj1.GetType().GetProperty(column).GetValue(obj1).ToString(), 
                                                          obj2.GetType().GetProperty(column).GetValue(obj2).ToString(), 
                                                          StringComparison.OrdinalIgnoreCase)
            Return If(sortOrder = "ASC", compareResult > 0, compareResult < 0)
        Case "beginnerstandard", "novicestandard", "intermediatestandard", "advancedstandard", "elitestandard"
            '数值类型字段比较
            Dim val1 As Integer = CInt(obj1.GetType().GetProperty(column).GetValue(obj1))
            Dim val2 As Integer = CInt(obj2.GetType().GetProperty(column).GetValue(obj2))
            Return If(sortOrder = "ASC", val1 > val2, val1 < val2)
        Case Else
            '无效字段，默认不交换
            Return False
    End Select
End Function

关键说明 #

1. 修正原代码错误：移除了无效的getArrayOfObjectsLength函数，直接使用List(Of T).Count获取列表长度，更高效准确。
2. 通用字段支持：通过反射获取指定字段的值，支持所有Exercises类的属性作为排序依据，无需为每个字段单独写判断逻辑。
3. 类型区分比较：针对字符串类型（如Name、Position）使用不区分大小写的文本比较，数值类型（如各等级标准）直接进行数值比较。
4. 提前终止优化：如果某一轮冒泡没有发生任何交换，说明列表已经有序，直接退出循环，减少不必要的遍历。
5. 参数类型明确：为bubbleSort方法的参数指定了类型（String），符合VB的类型安全要求。

使用示例 #

'示例：按Name字段升序排序
bubbleSort("ASC", "Name")

'示例：按beginnerStandard字段降序排序
bubbleSort("DESC", "beginnerStandard")

内容的提问来源于stack exchange，提问作者Manik Khadiya