Asp.net 从查询动态生成TreeView控件（VB.NET）_Asp.net_Vb.net_Treeview_Dataset

Asp.net 从查询动态生成TreeView控件（VB.NET）

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Asp.net 从查询动态生成TreeView控件（VB.NET）,asp.net,vb.net,treeview,dataset,Asp.net,Vb.net,Treeview,Dataset,我过去从未使用过TreeView，我想显示一个层次结构（n个级别的递归关系）。数据（在数据集中可用-从数据库查询检索）具有以下结构： __ID__ | __NAME__ | __PARENT__ 1 | Patrick | 2 | Mark | 3 | Scott | 2 4 | Jason | 5 | Julian | 6 | John | 6 7

我过去从未使用过TreeView，我想显示一个层次结构（n个级别的递归关系）。数据（在数据集中可用-从数据库查询检索）具有以下结构：

__ID__  | __NAME__  | __PARENT__ 
 1      | Patrick   |       
 2      | Mark      |
 3      | Scott     | 2
 4      | Jason     | 
 5      | Julian    |
 6      | John      | 6
 7      | Steve     |
 8      | George    | 1 
 9      | Robert    | 1
 10     | Rodney    | 8

我试图产生以下输出

- Patrick [1]
  - George [8]
    - Rodney [10]
  - Robert [9]

- Mark [2]
  - Scott [3]

- Julian [5]
  - John [6]

- Jason [4]

- Steve [7]

我正在尝试生成Treeview控件，但没有使用Treeview的经验。对于如何实现这一点的任何反馈或示例，我们都将不胜感激。

这里的重点是提供一种通用且适应性强的算法，能够执行所需的排序。一旦设置好，将值写入

TreeView

非常简单，只需添加

节点

和

子节点

    Dim NAME(10) As String
    Dim PARENT(10) As Integer
    Dim curID As Integer = 0

    curID = 1
    NAME(curID) = "Patrick [" & curID.ToString() & "]"
    PARENT(curID) = 0

    curID = curID + 1
    NAME(curID) = "Mark [" & curID.ToString() & "]"
    PARENT(curID) = 0

    curID = curID + 1
    NAME(curID) = "Scott [" & curID.ToString() & "]"
    PARENT(curID) = 2

    curID = curID + 1
    NAME(curID) = "Jason [" & curID.ToString() & "]"
    PARENT(curID) = 0

    curID = curID + 1
    NAME(curID) = "Julian [" & curID.ToString() & "]"
    PARENT(curID) = 0

    curID = curID + 1
    NAME(curID) = "John [" & curID.ToString() & "]"
    PARENT(curID) = 6

    curID = curID + 1
    NAME(curID) = "Steve [" & curID.ToString() & "]"
    PARENT(curID) = 0

    curID = curID + 1
    NAME(curID) = "George [" & curID.ToString() & "]"
    PARENT(curID) = 1

    curID = curID + 1
    NAME(curID) = "Robert [" & curID.ToString() & "]"
    PARENT(curID) = 1

    curID = curID + 1
    NAME(curID) = "Rodney [" & curID.ToString() & "]"
    PARENT(curID) = 8

    Dim completed As Boolean = False
    Dim firstIteration As Boolean = True
    Dim totIDs As Integer = 10

    Do
        curID = 0
        Do
            curID = curID + 1
            If (firstIteration) Then
                If (PARENT(curID) = 0 And TreeView1.FindNode(NAME(curID)) Is Nothing) Then
                    TreeView1.Nodes.Add(New TreeNode(NAME(curID)))
                End If
            Else
                If (PARENT(curID) > 0) Then
                    Dim targetNodes As TreeNodeCollection = TreeView1.Nodes
                    Dim count As Integer = 0

                    If (TreeView1.FindNode(NAME(curID)) Is Nothing) Then
                        For Each node As TreeNode In targetNodes
                            count = count + 1
                            If (node.Text.Contains("[" & PARENT(curID).ToString() & "]")) Then
                                node.ChildNodes.Add(New TreeNode(NAME(curID)))
                                Exit For
                            End If
                        Next
                    End If
                End If
            End If

        Loop While (curID < totIDs)

        If (firstIteration) Then
            firstIteration = False
        Else
            Exit Do 'Just two iterations
        End If
    Loop While (Not completed)

Dim名称（10）作为字符串
将父项（10）设置为整数
Dim curID为整数=0
库里=1
名称（curID）=“Patrick[”&curID.ToString（）&“]”
父（curID）=0
居里=居里+1
名称（curID）=“标记[”&curID.ToString（）&“]
父（curID）=0
居里=居里+1
名称（curID）=“Scott[”&curID.ToString（）&“”
父（curID）=2
居里=居里+1
名称（curID）=“Jason[”&curID.ToString（）&“]”
父（curID）=0
居里=居里+1
名称（curID）=“Julian[”&curID.ToString（）&“]”
父（curID）=0
居里=居里+1
NAME（curID）=“John[”&curID.ToString（）&“]”
父（curID）=6
居里=居里+1
NAME（curID）=“Steve[”&curID.ToString（）&“]”
父（curID）=0
居里=居里+1
名称（curID）=“George[”&curID.ToString（）&“]”
父（curID）=1
居里=居里+1
名称（curID）=“Robert[”&curID.ToString（）&“]”
父（curID）=1
居里=居里+1
名称（curID）=“Rodney[”&curID.ToString（）&“]
父（curID）=8
Dim已完成，布尔值=False
Dim firstIteration作为布尔值=真
Dim totIDs为整数=10
做
库里=0
做
居里=居里+1
如果（第一次迭代）那么
如果（PARENT（curID）=0且TreeView1.FindNode（NAME（curID））为空，则
添加（新树节点（名称（curID）））
如果结束
其他的
如果（父项（curID）>0），则
将targetNodes调暗为TreeNodeCollection=TreeView.Nodes
Dim计数为整数=0
如果（TreeView1.FindNode（NAME（curID））为空），那么
对于每个节点，作为targetNodes中的TreeNode
计数=计数+1
如果（node.Text.Contains（“[”&PARENT（curID.ToString（）&“]）），则
node.ChildNodes.Add（新树节点（名称（curID）））
退出
如果结束
下一个
如果结束
如果结束
如果结束
循环时间（curID


此代码依赖于两个数组（NAME
（字符串），其中还包括[original position]和PARENT
（整数）），并执行包含，直到“第二级”，即主节点和第一个子节点
我想您将有足够的信息来理解如何处理TreeView
，并构建能够执行所需排序的算法。
要从数据表填充TreeView，请尝试以下代码
Dim DataTable1 As New DataTable

Private Sub FillTestTable()
    DataTable1.Columns.Add("ID", GetType(Integer))
    DataTable1.Columns.Add("NAME", GetType(String))
    DataTable1.Columns.Add("PARENT", GetType(Integer))
    DataTable1.Columns.Add("LEVEL", GetType(Integer))

    DataTable1.Rows.Add(1, "Patrick")
    DataTable1.Rows.Add(2, "Mark")
    DataTable1.Rows.Add(3, "Scott", 2)
    DataTable1.Rows.Add(4, "Jason")
    DataTable1.Rows.Add(5, "Julian")
    DataTable1.Rows.Add(6, "John", 5)
    DataTable1.Rows.Add(7, "Steve")
    DataTable1.Rows.Add(8, "George", 1)
    DataTable1.Rows.Add(9, "Robert", 1)
    DataTable1.Rows.Add(10, "Rodney", 8)

    Dim i As Integer

    For i = 0 To DataTable1.Rows.Count - 1
        Dim ID1 As String = DataTable1.Rows(i).Item("ID").ToString
        DataTable1.Rows(i).Item("LEVEL") = FindLevel(ID1, 0)
    Next
End Sub

Private Function FindLevel(ByVal ID As String, ByRef Level As Integer) As Integer
    Dim i As Integer

    For i = 0 To DataTable1.Rows.Count - 1
        Dim ID1 As String = DataTable1.Rows(i).Item("ID").ToString
        Dim Parent1 As String = DataTable1.Rows(i).Item("PARENT").ToString

        If ID = ID1 Then
            If Parent1 = "" Then
                Return Level
            Else
                Level += 1
                FindLevel(Parent1, Level)
            End If
        End If
    Next

    Return Level
End Function

VB.NET WindowsForms应用程序的代码
Private Sub CreateTree()
    Dim MaxLevel1 As Integer = CInt(DataTable1.Compute("MAX(LEVEL)", ""))

    Dim i, j As Integer

    For i = 0 To MaxLevel1
        Dim Rows1() As DataRow = DataTable1.Select("LEVEL = " & i)

        For j = 0 To Rows1.Count - 1
            Dim ID1 As String = Rows1(j).Item("ID").ToString
            Dim Name1 As String = Rows1(j).Item("NAME").ToString
            Dim Parent1 As String = Rows1(j).Item("PARENT").ToString

            If Parent1 = "" Then
                TreeView1.Nodes.Add(ID1, Name1)
            Else
                Dim TreeNodes1() As TreeNode = TreeView1.Nodes.Find(Parent1, True)

                If TreeNodes1.Length > 0 Then
                    TreeNodes1(0).Nodes.Add(ID1, Name1)
                End If
            End If
        Next
    Next
End Sub

Private Sub Button1_Click(sender As System.Object, e As System.EventArgs) Handles Button1.Click
    FillTestTable()
    CreateTree()
    TreeView1.ExpandAll()
End Sub

Private Sub CreateTree()
    Dim MaxLevel1 As Integer = CInt(DataTable1.Compute("MAX(LEVEL)", ""))

    Dim i, j As Integer

    For i = 0 To MaxLevel1
        Dim Rows1() As DataRow = DataTable1.Select("LEVEL = " & i)

        For j = 0 To Rows1.Count - 1
            Dim ID1 As String = Rows1(j).Item("ID").ToString
            Dim Name1 As String = Rows1(j).Item("NAME").ToString
            Dim Parent1 As String = Rows1(j).Item("PARENT").ToString

            If Parent1 = "" Then
                TreeView1.Nodes.Add(New TreeNode(Name1, ID1))
            Else
                Dim Node1 As TreeNode = GetChildByValue(Parent1, TreeView1.Nodes)

                If Not Node1 Is Nothing Then
                    Node1.ChildNodes.Add(New TreeNode(Name1, ID1))
                End If
            End If
        Next
    Next
End Sub

Private Function GetChildByValue(ByVal ID1 As String, ByVal NodeCollection1 As TreeNodeCollection) As TreeNode
    For Each TreeNode1 As TreeNode In NodeCollection1
        If TreeNode1.Value = ID1 Then
            Return TreeNode1
        Else
            Dim TreeNode2 As TreeNode = GetChildByValue(ID1, TreeNode1.ChildNodes)

            If Not TreeNode2 Is Nothing Then
                Return TreeNode2
            End If
        End If
    Next

    Return Nothing
End Function

Protected Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
    FillTestTable()
    CreateTree()
    TreeView1.ExpandAll()
End Sub

ASP.NET应用程序的代码
Private Sub CreateTree()
    Dim MaxLevel1 As Integer = CInt(DataTable1.Compute("MAX(LEVEL)", ""))

    Dim i, j As Integer

    For i = 0 To MaxLevel1
        Dim Rows1() As DataRow = DataTable1.Select("LEVEL = " & i)

        For j = 0 To Rows1.Count - 1
            Dim ID1 As String = Rows1(j).Item("ID").ToString
            Dim Name1 As String = Rows1(j).Item("NAME").ToString
            Dim Parent1 As String = Rows1(j).Item("PARENT").ToString

            If Parent1 = "" Then
                TreeView1.Nodes.Add(ID1, Name1)
            Else
                Dim TreeNodes1() As TreeNode = TreeView1.Nodes.Find(Parent1, True)

                If TreeNodes1.Length > 0 Then
                    TreeNodes1(0).Nodes.Add(ID1, Name1)
                End If
            End If
        Next
    Next
End Sub

Private Sub Button1_Click(sender As System.Object, e As System.EventArgs) Handles Button1.Click
    FillTestTable()
    CreateTree()
    TreeView1.ExpandAll()
End Sub

Private Sub CreateTree()
    Dim MaxLevel1 As Integer = CInt(DataTable1.Compute("MAX(LEVEL)", ""))

    Dim i, j As Integer

    For i = 0 To MaxLevel1
        Dim Rows1() As DataRow = DataTable1.Select("LEVEL = " & i)

        For j = 0 To Rows1.Count - 1
            Dim ID1 As String = Rows1(j).Item("ID").ToString
            Dim Name1 As String = Rows1(j).Item("NAME").ToString
            Dim Parent1 As String = Rows1(j).Item("PARENT").ToString

            If Parent1 = "" Then
                TreeView1.Nodes.Add(New TreeNode(Name1, ID1))
            Else
                Dim Node1 As TreeNode = GetChildByValue(Parent1, TreeView1.Nodes)

                If Not Node1 Is Nothing Then
                    Node1.ChildNodes.Add(New TreeNode(Name1, ID1))
                End If
            End If
        Next
    Next
End Sub

Private Function GetChildByValue(ByVal ID1 As String, ByVal NodeCollection1 As TreeNodeCollection) As TreeNode
    For Each TreeNode1 As TreeNode In NodeCollection1
        If TreeNode1.Value = ID1 Then
            Return TreeNode1
        Else
            Dim TreeNode2 As TreeNode = GetChildByValue(ID1, TreeNode1.ChildNodes)

            If Not TreeNode2 Is Nothing Then
                Return TreeNode2
            End If
        End If
    Next

    Return Nothing
End Function

Protected Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
    FillTestTable()
    CreateTree()
    TreeView1.ExpandAll()
End Sub

谢谢你，大卫！我不得不将“TreeView1.Nodes.Add（ID1，Name1）”替换为“TreeView1.Nodes.Add（New TreeNode（ID1，Name1））”以下行“TreeView1.Nodes.Find（Parent1，True）（0）.Nodes.Add（ID1，Name1）”生成以下错误：“Find”不是“System.Web.UI.WebControls.TreeNodeCollection”的成员我的初始代码是针对Windows窗体应用程序的，请参阅ASP.NET版本的编辑代码。我还对代码做了一些改进。