Kako izvesti da snimate sadržaj kontrole TreeView-a i kako da „napunite“ TreeView podacima? Ovo ćemo izvesti pomoću „Contents“ osobine, objekta „PropertyBag“ (VB6). Kod sadrži dve javne rutine (Sub) zvane „SaveTree“ i „LoadTree„. „SaveTree“ procedura ima 3 argumenta:
- file name – naziv fajla sa putem gde će biti snimljen fajl sa sadržajem TreeView-a
- root node – naziv čvora, drveta od koje želite da počnete snimanje
- SaveTree procedura poziva „private Sub“ nazvan „FillPropBag“ koji ima zadatak da popuni „PropertyBag“ (i to radi rekurzivno).
Private Sub FillPropBag(pb As PropertyBag, _
tvw As MSComctlLib.TreeView, Root As MSComctlLib.Node)
Static nCount As Long
Dim nde As MSComctlLib.Node
Dim nIndex As Long
If pb Is Nothing Then
Set pb = New PropertyBag
nCount = 0
pb.WriteProperty „NumberOfNodes“, tvw.Nodes.Count, 0
End If
On Error Resume Next
pb.WriteProperty „Text“ & nCount, Root.Text
nIndex = Root.Parent.Index
If nCount = 0 Then
nIndex = 0
End If
pb.WriteProperty „Parent“ & nCount, nIndex, 0
pb.WriteProperty „Key“ & nCount, Root.Key, „“
pb.WriteProperty „Index“ & nCount, Root.Index, 0
pb.WriteProperty „Image“ & nCount, Root.Image, vbEmpty
pb.WriteProperty „SelectedImage“ & nCount, _
Root.SelectedImage, vbEmpty
Set nde = Root.Child
If nde Is Nothing Then
Set nde = Root.Next
If nde Is Nothing Then
Exit Sub
End If
End If
nCount = nCount + 1
FillPropBag pb, tvw, nde
End Sub
Public Sub SaveTree(sFilename As String, _
tvw As MSComctlLib.TreeView, Root As MSComctlLib.Node)
Dim pb As PropertyBag
Dim bArr() As Byte
Dim iFile As Integer
FillPropBag pb, tvw, Root
iFile = FreeFile
Open sFilename For Binary Access Write As #iFile
bArr = pb.Contents
Put #iFile, , bArr
Close #iFile
End Sub
Public Sub LoadTree(sFilename As String, _
tvw As MSComctlLib.TreeView)
Dim pb As PropertyBag
Dim bArr() As Byte
Dim iFile As Integer
Dim nde As MSComctlLib.Node
Dim nCount As Long
Dim nNumOfNodes As Long
Dim nIndex As Long
Dim sText$, sKey$
Dim nParent As Long
Dim vImage, vSelectedImage
iFile = FreeFile
Open sFilename For Binary Access Read As #iFile
ReDim bArr(LOF(iFile)) As Byte
Get #iFile, , bArr
Close #iFile
Set pb = New PropertyBag
pb.Contents = bArr
tvw.Nodes.Clear
nNumOfNodes = pb.ReadProperty(„NumberOfNodes“, 0)
If nNumOfNodes = 0 Then
Exit Sub
nd If
Do While nCount <nNumOfNodes
nParent = pb.ReadProperty(„Parent“ & nCount, 0)
nIndex = pb.ReadProperty(„Index“ & nCount, 0)
sKey = pb.ReadProperty(„Key“ & nCount, „“)
sText = pb.ReadProperty(„Text“ & nCount, „“)
vImage = pb.ReadProperty(„Image“ & nCount, vbEmpty)
vSelectedImage = pb.ReadProperty(„SelectedImage“ _
& nCount, vbEmpty)
If nParent Then
tvw.Nodes.Add tvw.Nodes(nParent), tvwChild, sKey, _
sText, vImage, vSelectedImage
Else
tvw.Nodes.Add , , sKey, sText, vImage, vSelectedImage
End If
nCount = nCount + 1
Loop
End Sub
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