树和自联表(一)-.NET教程,评论及其它

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树和自联表(一)

作者：未知

日期：2006-12-01

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以下正文：

Author：水如烟

自联表我们经常用到，它总是跟树联结在一起。
对于它们的处理，.NET没有专门的处理类。
控件类TreeNode，也没有直接跟自联表挂上钩。

所以，我也尝试一下写写这方面的代码。
如我以往所写的一样，仅提供一种方法，至于更好的方法，更好的效率，鉴于自己学识所限，不深究。

通常的，要做成泛型类才能通用。所以，若还是使用.Net FrameWork1.1的话，无法使用下面的类了。

下面是为应用自联表做的树类，只有两个文件：
Node.vb

Namespace LzmTW.uSystem.uCollection

    <Serializable()> _
    Public Class Node(Of T)

        Friend gIsRoot As Boolean = True
        Friend gParent As Node(Of T)

        ''' <summary>
        ''' 当前节点的父节点
        ''' </summary>
        Public ReadOnly Property Parent() As Node(Of T)
            Get
                If Me.IsRoot Then
                    Return Nothing
                End If
                Return gParent
            End Get
        End Property

        ''' <summary>
        ''' 树的深度
        ''' </summary>
        Public ReadOnly Property Level() As Integer
            Get
                If Me.IsRoot Then
                    Return 0
                End If
                Return Me.Parent.Level + 1
            End Get
        End Property

        ''' <summary>
        ''' 当前节点是否是根节点
        ''' </summary>
        Public ReadOnly Property IsRoot() As Boolean
            Get
                Return gIsRoot
            End Get
        End Property

        Private gUserData As Object

        ''' <summary>
        ''' 获取或设置包含树节点有关数据的对象
        ''' </summary>
        Public Property Tag() As Object
            Get
                Return gUserData
            End Get
            Set(ByVal value As Object)
                gUserData = value
            End Set
        End Property

        Private gItem As T
        Public Property Item() As T
            Get
                Return gItem
            End Get
            Set(ByVal value As T)
                gItem = value
            End Set
        End Property

        Friend gChildren As NodeCollection(Of T)

        ''' <summary>
        ''' 获取第一个子树节点
        ''' </summary>
        Public ReadOnly Property FirstNode() As Node(Of T)
            Get
                If gChildren.Count = 0 Then
                    Return Nothing
                End If
                Return gChildren(0)
            End Get
        End Property

        ''' <summary>
        ''' 获取最后一个子树节点
        ''' </summary>
        Public ReadOnly Property LastNode() As Node(Of T)
            Get
                If gChildren.Count = 0 Then
                    Return Nothing
                End If
                Return gChildren(gChildren.Count - 1)
            End Get
        End Property

        Private gNodes As NodeCollection(Of T)

        ''' <summary>
        ''' 当前节点的节点集合
        ''' </summary>
        Public ReadOnly Property Nodes() As NodeCollection(Of T)
            Get
                Return gNodes
            End Get
        End Property

        ''' <summary>
        ''' 当前节点在节点集合中的位置
        ''' </summary>
        Public ReadOnly Property Index() As Integer
            Get
                Return GetIndex()
            End Get
        End Property

        Private Function GetIndex() As Integer
            If Me.IsRoot Then
                Return 0
            End If

            Return Me.Parent.Nodes.IndexOf(Me)
        End Function

        ''' <summary>
        ''' 获取下一个同级树节点
        ''' </summary>
        Public ReadOnly Property NextNode() As Node(Of T)
            Get
                If Me.IsRoot OrElse Me.Index + 1 > Me.Parent.Nodes.Count Then
                    Return Nothing
                End If

                Return Me.Parent.Nodes.Item(Me.Index + 1)
            End Get
        End Property

        ''' <summary>
        ''' 获取上一个同级树节点
        ''' </summary>
        Public ReadOnly Property PrevNode() As Node(Of T)
            Get
                If Me.IsRoot OrElse Me.Index - 1 < 0 Then
                    Return Nothing
                End If

                Return Me.Parent.Nodes.Item(Me.Index - 1)
            End Get
        End Property

        Private Sub Initialzie()
            gNodes = New NodeCollection(Of T)(Me)
            gChildren = New NodeCollection(Of T)(Me)
            gByProperty = Not uSystem.uReflection.CommonFunction.TypeHasFields(GetType(T))
        End Sub

        Sub New()
            Initialzie()
        End Sub

        Sub New(ByVal item As T)
            gItem = item

            Initialzie()
        End Sub

        Public Function GetNodeCount(ByVal includeSubNodes As Boolean) As Integer
            Dim mCount As Integer = gChildren.Count
            If includeSubNodes Then
                Dim mIndex As Integer = 0
                Do While mIndex < gChildren.Count
                    mCount += gChildren(mIndex).GetNodeCount(True)
                    mIndex += 1
                Loop
            End If

            Return mCount
        End Function

        Public Sub Remove()
            If Me.IsRoot Then
                Throw New Exception("不能移除根节点")
            End If
            Me.Parent.Nodes.RemoveAt(Me.Index)
        End Sub

        Private gTable As DataTable
        Private gByProperty As Boolean

        ''' <summary>
        ''' 将当前节点树转换为表
        ''' </summary>
        ''' <param name="includeSubNodes">是否包括子节点的T对象</param>
        Public Function ConvertToDataTable(ByVal includeSubNodes As Boolean) As DataTable
            gTable = uSystem.uReflection.CommonFunction.CreateTableFromType(GetType(T))

            If gTable.Columns.Count = 0 Then
                If gByProperty Then
                    Throw New Exception("对象无属性列")
                Else
                    Throw New Exception("对象无字段列")
                End If
            End If

            Me.ForEach(New Action(Of T)(AddressOf GetDataTableDatasAction), includeSubNodes)

            gTable.AcceptChanges()

            Return gTable
        End Function

        Private Sub GetDataTableDatasAction(ByVal item As T)
            uSystem.uReflection.CommonFunction.ItemAppendToTable(Of T)(item, gTable)
        End Sub

        ''' <summary>
        ''' 将当前节点树转换为TreeNode
        ''' </summary>
        ''' <param name="NameOfTreeNodeText">TreeNode的Text值对应的T对象属性名或字段名</param>
        ''' <param name="includeSubNodes">是否包括子节点</param>
        ''' <remarks>TreeNode的Tag存T对象值</remarks>
        Public Function ConvertToTreeNode(ByVal nameOfTreeNodeText As String, ByVal includeSubNodes As Boolean) As Windows.Forms.TreeNode
            CheckValid(gByProperty, nameOfTreeNodeText)

            Dim mTreeNode As System.Windows.Forms.TreeNode = ConvertToTreeNode(Me, gByProperty, nameOfTreeNodeText)

            If includeSubNodes Then AppendTreeNode(mTreeNode, Me, gByProperty, nameOfTreeNodeText)

            Return mTreeNode
        End Function

        Private Shared Sub AppendTreeNode(ByVal treeNode As Windows.Forms.TreeNode, ByVal node As Node(Of T), ByVal byProperty As Boolean, ByVal nameOfTreeNodeText As String)
            For Each n As Node(Of T) In node.gChildren

                Dim mCurrentTreeNode As Windows.Forms.TreeNode = ConvertToTreeNode(n, byProperty, nameOfTreeNodeText)

                treeNode.Nodes.Add(mCurrentTreeNode)

                AppendTreeNode(mCurrentTreeNode, n, byProperty, nameOfTreeNodeText)

            Next

        End Sub

        Private Shared Function ConvertToTreeNode(ByVal node As Node(Of T), ByVal byProperty As Boolean, ByVal nameOfTreeNodeText As String) As System.Windows.Forms.TreeNode
            Dim mTextValue As Object

            If byProperty Then
                mTextValue = GetType(T).GetProperty(nameOfTreeNodeText).GetValue(node.Item, Nothing)
            Else
                mTextValue = GetType(T).GetField(nameOfTreeNodeText).GetValue(node.Item)
            End If

            If mTextValue Is Nothing Then
                mTextValue = "Root"
            End If

            Dim mTreeNode As New System.Windows.Forms.TreeNode(mTextValue.ToString)
            mTreeNode.Tag = node.Item

            Return mTreeNode
        End Function

        Private Sub CheckValid(ByVal byProperty As Boolean, ByVal nameOfTreeNodeText As String)
            If byProperty Then
                Dim mPropertyInfo As System.Reflection.PropertyInfo = GetType(T).GetProperty(nameOfTreeNodeText)
                If mPropertyInfo Is Nothing Then
                    Throw New Exception("属性名无效")
                    If Not mPropertyInfo.CanRead Then
                        Throw New Exception("属性名不可读")
                    End If
                End If
            Else
                Dim mFieldInfo As System.Reflection.FieldInfo = GetType(T).GetField(nameOfTreeNodeText)
                If mFieldInfo Is Nothing Then
                    Throw New Exception("字段名无效")
                End If
            End If
        End Sub

        ''' <summary>
        ''' 对每个节点执行指定操作
        ''' </summary>
        ''' <param name="action">对指定的对象执行操作的方法</param>
        ''' <param name="includeSubNodes">是否包括子节点</param>
        Public Sub ForEach(ByVal action As Action(Of Node(Of T)), ByVal includeSubNodes As Boolean)
            Node(Of T).ForEach(Me, action, includeSubNodes)
        End Sub

        Public Shared Sub ForEach(ByVal node As Node(Of T), ByVal action As Action(Of Node(Of T)), ByVal includeSubNodes As Boolean)
            For Each n As Node(Of T) In node.gChildren
                action.Invoke(n)

                If includeSubNodes Then ForEach(n, action, True)
            Next
        End Sub

        ''' <summary>
        ''' 对每个T对象执行指定操作
        ''' </summary>
        ''' <param name="action">对指定的对象执行操作的方法</param>
        ''' <param name="includeSubNodes">是否包括子节点的T对象</param>
        Public Sub ForEach(ByVal action As Action(Of T), ByVal includeSubNodes As Boolean)
            Node(Of T).ForEach(Me, action, includeSubNodes)
        End Sub

        Public Shared Sub ForEach(ByVal node As Node(Of T), ByVal action As Action(Of T), ByVal includeSubNodes As Boolean)
            For Each n As Node(Of T) In node.gChildren
                action.Invoke(n.Item)

                If includeSubNodes Then ForEach(n, action, True)
            Next
        End Sub

        Public Function Clone() As Node(Of T)
            Return uSystem.uRuntime.uSerialization.SerializeHelper.Clone(Of Node(Of T))(Me)
        End Function

    End Class

End Namespace

NodeCollection.vb

Namespace LzmTW.uSystem.uCollection

    <Serializable()> _
    Public Class NodeCollection(Of T)
        Inherits System.Collections.ObjectModel.Collection(Of Node(Of T))

        Private gOwner As Node(Of T)

        Friend Sub New(ByVal node As Node(Of T))
            gOwner = node
        End Sub

        Public Shadows Function Add(ByVal Value As T) As Node(Of T)
            Dim mNode As New Node(Of T)(Value)

            Add(mNode)
            gOwner.gChildren.Add(mNode)

            Return mNode
        End Function

        Private Shadows Sub Add(ByVal item As Node(Of T))
            With item
                .gParent = gOwner
                .gIsRoot = False
            End With

            MyBase.Add(item)
        End Sub

        Public Shadows Sub RemoveAt(ByVal index As Integer)
            If Not IsValidIndex(index) Then
                Throw New Exception("索引无效")
            End If

            Dim mNode As Node(Of T) = Me.Item(index)
            Remove(mNode)

            gOwner.gChildren.Remove(mNode)
        End Sub

        Public Shadows Sub Remove(ByVal index As Integer)
            Me.RemoveAt(index)
        End Sub

        Private Shadows Function Remove(ByVal item As Node(Of T)) As Boolean
            Return MyBase.Remove(item)
        End Function

        Public Shadows Sub Insert(ByVal index As Integer, ByVal Value As T)
            If Not IsValidIndex(index) Then
                Throw New Exception("索引无效")
            End If

            Dim mNode As New Node(Of T)(Value)

            Insert(index, mNode)
            gOwner.gChildren.Insert(index, mNode)
        End Sub

        Private Shadows Sub Insert(ByVal index As Integer, ByVal item As Node(Of T))
            With item
                .gParent = gOwner
                .gIsRoot = False
            End With

            MyBase.Insert(index, item)
        End Sub

        Public Overloads Sub Clear()
            MyBase.Clear()
            If gOwner.gChildren.Count > 0 Then gOwner.gChildren.Clear()
        End Sub

        Private Function IsValidIndex(ByVal index As Integer) As Boolean
            If index >= 0 Then
                Return index < Me.Count
            End If

            Return False
        End Function

    End Class
End Namespace

两个辅助的类，专用于序列化、反射取值赋值用的。
SerializeHelper.vb

Namespace LzmTW.uSystem.uRuntime.uSerialization

    Public Class SerializeHelper

        Private Sub New()
        End Sub

        <System.ComponentModel.EditorBrowsable(System.ComponentModel.EditorBrowsableState.Advanced)> _
        Public Shared Function ItemToXml(Of T)(ByVal obj As T) As String
            Dim mResult As String = ""
            Dim mSerializer As New System.Xml.Serialization.XmlSerializer(GetType(T))
            Dim mStringWriter As New System.IO.StringWriter
            Using mStringWriter
                mSerializer.Serialize(mStringWriter, obj)
                mResult = mStringWriter.ToString
                mStringWriter.Close()
            End Using
            Return mResult
        End Function

        <System.ComponentModel.EditorBrowsable(System.ComponentModel.EditorBrowsableState.Advanced)> _
        Public Shared Function XmlToItem(Of T)(ByVal xml As String) As T
            Dim mSerializer As New System.Xml.Serialization.XmlSerializer(GetType(T))
            Dim mStringReader As New System.IO.StringReader(xml)
            Return CType(mSerializer.Deserialize(mStringReader), T)
        End Function

        <System.ComponentModel.EditorBrowsable(System.ComponentModel.EditorBrowsableState.Advanced)> _
        Public Shared Sub ItemToXmlFile(Of T)(ByVal filename As String, ByVal obj As T)
            Dim XmlWriter As New System.IO.StreamWriter(filename, False, System.Text.Encoding.Default)
            Using XmlWriter
                XmlWriter.Write(ItemToXml(obj))
                XmlWriter.Close()
            End Using
        End Sub

        <System.ComponentModel.EditorBrowsable(System.ComponentModel.EditorBrowsableState.Advanced)> _
        Public Shared Function XmlFileToItem(Of T)(ByVal filename As String) As T
            Dim XmlReader As New System.IO.StreamReader(filename, System.Text.Encoding.Default)
            Dim mObj As T
            Using XmlReader
                mObj = XmlToItem(Of T)(XmlReader.ReadToEnd)
                XmlReader.Close()
            End Using
            Return mObj
        End Function

        <System.ComponentModel.EditorBrowsable(System.ComponentModel.EditorBrowsableState.Advanced)> _
        Public Shared Sub ItemToFormatterFile(Of T)(ByVal filename As String, ByVal formatter As System.Runtime.Serialization.IFormatter, ByVal obj As T)
            Dim mFileStream As System.IO.Stream = System.IO.File.Open(filename, System.IO.FileMode.Create)
            Using mFileStream
                formatter.Serialize(mFileStream, obj)
                mFileStream.Close()
            End Using
        End Sub

        <System.ComponentModel.EditorBrowsable(System.ComponentModel.EditorBrowsableState.Advanced)> _
        Public Shared Function FormatterFileToItem(Of T)(ByVal FileName As String, ByVal formatter As System.Runtime.Serialization.IFormatter) As T
            Dim mFileStream As System.IO.Stream = System.IO.File.Open(FileName, System.IO.FileMode.Open)
            Dim mObj As T
            Using mFileStream
                mObj = CType(formatter.Deserialize(mFileStream), T)
                mFileStream.Close()
            End Using
            Return mObj
        End Function

        Public Shared Function Clone(Of T)(ByVal obj As T) As T
            Dim tmpT As T
            Dim mFormatter As New System.Runtime.Serialization.Formatters.Binary.BinaryFormatter
            Dim mMemoryStream As New System.IO.MemoryStream
            Using mMemoryStream
                mFormatter.Serialize(mMemoryStream, obj)
                mMemoryStream.Position = 0
                tmpT = CType(mFormatter.Deserialize(mMemoryStream), T)
                mMemoryStream.Close()
            End Using
            Return tmpT
        End Function

        Public Shared Sub Save(Of T)(ByVal filename As String, ByVal formattype As FormatType, ByVal obj As T)
            Select Case formattype
                Case formattype.Binary
                    ItemToFormatterFile(filename, New System.Runtime.Serialization.Formatters.Binary.BinaryFormatter, obj)
                Case formattype.Soap
                    ItemToFormatterFile(filename, New System.Runtime.Serialization.Formatters.Soap.SoapFormatter, obj)
                Case formattype.Xml
                    ItemToXmlFile(filename, obj)
            End Select
        End Sub

        Public Shared Function Load(Of T)(ByVal filename As String, ByVal formattype As FormatType) As T
            Select Case formattype
                Case formattype.Binary
                    Return FormatterFileToItem(Of T)(filename, New System.Runtime.Serialization.Formatters.Binary.BinaryFormatter)
                Case formattype.Soap
                    Return FormatterFileToItem(Of T)(filename, New System.Runtime.Serialization.Formatters.Soap.SoapFormatter)
                Case formattype.Xml
                    Return XmlFileToItem(Of T)(filename)
            End Select
            Return Nothing
        End Function

    End Class

    Public Enum FormatType
        Xml
        Binary
        Soap
    End Enum

End Namespace

ReflectionCommonFunction.vb

Namespace LzmTW.uSystem.uReflection
    Public Class CommonFunction
        Private Sub New()
        End Sub

        Public Shared Function TypeHasFields(ByVal t As Type) As Boolean
            Return t.GetFields.Length >