递归过程在VB中的应用实例

Dim nodx As Node

Private Sub Form_Load()

'在 ImageList 控件中添加一个图象。

Dim imgX As ListImage

' TreeView1.ImageList = ImageList1 '初始化ImageList。

Set imgX = ImageList1.ListImages.Add(, , _

LoadPicture("c:\my documents\072.bmp"))

TreeView1.ImageList = ImageList1 '初始化ImageList。

TreeView1.LineStyle = tvwRootLines

TreeView1.Style = tvwTreelinesPlusMinusPictureText

Dim DriverCount As Integer

Dim GivePath As String

On Error Resume Next

'创建根节点

Set nodx = TreeView1.Nodes.Add(, , "本人电脑", "本人电脑", 1)

For DriverCount = 0 To Drive1.ListCount - 1

Set nodx = TreeView1.Nodes.Add("本人电脑", tvwChild, _

Drive1.List(DriverCount) + "\", _

Drive1.List(DriverCount), 1)

GivePath = Drive1.List(DriverCount) + "\"

Call SSplitNode(GivePath)

Next DriverCount

End Sub

Sub SSplitNode(GivePath As String) ‘子过程

'把给定目录下的子目录全部加入Node对象中

Dim SDI As Integer

Dim SDCount As Integer

Dim DString(1000) As String

‘以下为展开给定目录的下级子目录

Dir1.Path = GivePath ‘给定目录

SDCount = Dir1.ListCount ‘利用Dir1控件判断是否有下级目录

If SDCount = 0 Then Exit Sub

‘如无同退出子程序,即为递归出口。否则会形成死循环。

For SDI = 0 To SDCount - 1

DString(SDI) = Dir1.List(SDI)

Set nodx = TreeView1.Nodes.Add(GivePath, tvwChild, _

DString(SDI), FOnlyPath(DString(SDI)), 1)

Next SDI

‘调用递归(子程序自己调用自己)

For SDI = 0 To SDCount - 1

Call SSplitNode(DString(SDI))

Next SDI

End Sub

Function FOnlyPath(DString As String) As String

'功能是去掉上级目录，只留下当前目录名

'DString为给定的全路径目录名

If DString = "" Then Exit Function

Dim DLength As Integer

DLength = Len(DString)

Dim DD As Integer

For DD = DLength To 1 Step -1

If Mid(DString, DD, 1) = "\" Then Exit For

Next DD

FOnlyPath = Mid(DString, DD + 1)

End Function