Define and use a generic Tree data structure : Generic Tree « Generics « VB.Net





Define and use a generic Tree data structure

Define and use a generic Tree data structure
Imports System
Imports System.Windows.Forms
Imports System.Collections.Generic
Imports System.ComponentModel

Public Class MainClass

   Shared Sub Main()
        Dim family_tree As New Tree(Of Person)
        Dim root As TreeNode(Of Person) = _
            family_tree.MakeRoot(New Person("Root"))

        Dim child1 As TreeNode(Of Person) = _
            root.AddChild(New Person("First Level Node 1"))
        Dim child2 As TreeNode(Of Person) = _
            root.AddChild(New Person("First Level Node 2"))

        child1.AddChild(New Person("Leap 1"))
        child1.AddChild(New Person("Leap 2"))
        child2.AddChild(New Person("Leap 3"))
        child2.AddChild(New Person("Leap 4"))

        ' Display the result.
        Console.WriteLine(family_tree.ToString())
   End Sub 

End Class



Public Class Person
    Public Name As String
    Public Sub New(ByVal new_name As String)
        Name = new_name
    End Sub
    Public Overrides Function ToString() As String
        Return Name
    End Function
End Class


Public Class Tree(Of data_type)
    Private m_Root As TreeNode(Of data_type) = Nothing
    <Description("The tree's root node."), _
     Category("Data")> _
    Public Property Root() As TreeNode(Of data_type)
        Get
            Return m_Root
        End Get
        Set(ByVal value As TreeNode(Of data_type))
            m_Root = value
        End Set
    End Property

    Public Sub Clear()
        m_Root = Nothing
    End Sub

    Public Function MakeRoot(ByVal node_item As data_type) As TreeNode(Of data_type)
        m_Root = New TreeNode(Of data_type)(node_item)
        Return m_Root
    End Function

    Public Overrides Function ToString() As String
        Return m_Root.ToString()
    End Function
End Class

Public Class TreeNode(Of data_type)
    Public NodeObject As data_type
    Public Children As New List(Of TreeNode(Of data_type))

    Public Sub New(ByVal node_object As data_type)
        NodeObject = node_object
    End Sub

    Public Function AddChild(ByVal node_item As data_type) As TreeNode(Of data_type)
        Dim child_node As New TreeNode(Of data_type)(node_item)
        Children.Add(child_node)
        Return child_node
    End Function

    Public Shadows Function ToString(Optional ByVal indent As Integer = 0) As String
        Dim txt As String
        txt = New String(" "c, indent) & NodeObject.ToString & vbCrLf

        For Each child As TreeNode(Of data_type) In Children
            txt &= child.ToString(indent + 2)
        Next child

        Return txt
    End Function
End Class

           
       










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