编辑目录树之一

本节内容可以参考CaseStudy目录下的文件：目录树管理.Table

假定并不想用表来存储目录结构，而是希望通过一个文本文件存储，并希望能够让修改并保存目录树结构。
实现这样的任务并不复杂，我们假定存储目录树结构的文件名“product.foxtr”,位于项目文件目录下。

设计的步骤为：

1、首先设计一个下图所示的窗口：

2、窗口的AfterLoad事件设置为：

Dim tr As WinForm.TreeView = e.Form.Controls("TreeView1")
Dim fn As String = ProjectPath & "Product.foxtr"
If Filesys.FileExists(fn) Then
    tr.Load(fn)
End If

3、按下表所示设置各按钮的Click事件代码：

名称 代码
重命名 Dim tr As WinForm.TreeView
tr = e.Form.Controls("TreeView1")
tr.Select()
tr.BeginEdit()
增加根节点 Dim tr As WinForm.TreeView
Dim nd As WinForm.TreeNode
tr = e.Form.Controls("TreeView1")
nd = tr.Nodes.Add("新节点")
tr.SelectedNode = nd
tr.Select()
tr.BeginEdit()
增加子节点 Dim tr As WinForm.TreeView
Dim nd As WinForm.TreeNode
tr = e.Form.Controls("TreeView1")
nd = tr.SelectedNode
If nd IsNot Nothing Then
    nd = nd.Nodes.Add("新节点")
    tr.SelectedNode = nd
    tr.Select
    tr.BeginEdit
End If
插入节点 Dim tr As WinForm.TreeView = e.Form.Controls("TreeView1")
Dim nd As WinForm.TreeNode = tr.SelectedNode
Dim id As Integer = nd.index
If nd.ParentNode Is Nothing Then
    nd = tr.Nodes.Insert("新节点",id)
Else
    nd = nd.ParentNode.Nodes.Insert("新节点",id)
End If
tr.SelectedNode = nd
tr.Select
tr.BeginEdit
上移 Dim tr As WinForm.TreeView = e.Form.Controls("TreeView1")
Dim nd As WinForm.TreeNode = tr.SelectedNode
If nd IsNot Nothing Then
    nd.MoveUp()
End If
tr.Select
下移 Dim tr As WinForm.TreeView = e.Form.Controls("TreeView1")
Dim nd As WinForm.TreeNode = tr.SelectedNode
If nd IsNot Nothing Then
    nd.MoveDown()
End If
tr.Select
左移 Dim tr As WinForm.TreeView = e.Form.Controls("TreeView1")
Dim nd As WinForm.TreeNode = tr.SelectedNode
If nd IsNot Nothing Then
    nd.MoveLeft()
End If
tr.Select
右移 Dim tr As WinForm.TreeView = e.Form.Controls("TreeView1")
Dim nd As WinForm.TreeNode = tr.SelectedNode
If nd IsNot Nothing Then
    nd.MoveRight()
End If
tr.Select
删除 Dim tr As WinForm.TreeView = e.Form.Controls("TreeView1")
Dim nd As WinForm.TreeNode = tr.SelectedNode
If nd IsNot Nothing Then
    nd.Delete
End If
tr.Select
保存 Dim tr As WinForm.TreeView = e.Form.Controls("TreeView1")
Dim fn As String = ProjectPath & "Product.foxtr"
tr.Save(fn)

4、实际上，重命名节点修改的只是节点标题，而不是节点名称，所以我们还需要在AfterEditNode事件中设置代码，使得节点名称和标题保持一致：

e.Node.Name = e.NewText

5、下图是设计效果，用户可以并保存修改目录树结构：

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