Saving contents of a treeview into a textfile

[ranma_at]

Hi,

has anyone a codesnippet for storing a treeview with all its nodes and childs into a textfile, somehow sorted so the nodes dont get lost?

thanks :-)

[Eras3r]

nested for-loops......

[Shawn N]

Actually the function would have to be recursive since you have no idea how many loops you would need.

[Eras3r]

well, do you know before hand how many levels in the tree goes?

[Shawn N]

I'm not sure if you're asking me or not, but if you are: No I don't know and that's why I suggest a recursive function to save. Going this route would make the number of nests in the treeview irrelevant.

[Eras3r]

I havent used the treeview in some years... But wasn't there a property that told you how many levels were underneath a specific node?

[brucevde]

The easiest way would be to create a UDT that represents a record in your file. This udt holds the data you want to save for each node. Make sure you include the Node.Key and the Node.Parent.Key.

Then just loop through all the nodes, no recursive function is neccessary, and write out the data. Loading the tree simply becomes a matter of running through the file, creating a node for every record.

Private Type NodeType
    ParentKey As String * 20
    Key As String * 20
    Text As String * 50
    Bold As Boolean
    Color As Long
End Type
 
 
Private Sub SaveTreeToFile()
    Dim lngFile As Long
    Dim objNode As Node
    Dim udtNodeData As NodeType
    
    'just overwrite the existing file
    lngFile = FreeFile
    Open "D:\Testing\Treeview.dat" For Binary As lngFile
    
    For Each objNode In Treeview1.Nodes
        
        If Not objNode.Parent Is Nothing Then
            udtNodeData.ParentKey = objNode.Parent.Key
        Else
            udtNodeData.ParentKey = ""
        End If
        
        udtNodeData.Key = objNode.Key
        udtNodeData.Text = objNode.Text
        udtNodeData.Bold = objNode.Bold
        udtNodeData.Color = objNode.ForeColor
        
        Put lngFile, , udtNodeData
    Next
    
    Close lngFile
End Sub
 
Private Sub LoadTreeFromFile()
    Dim lngFile As Long
    Dim objNode As Node
    Dim udtNodeData As NodeType
    
    Dim strParent As String
    Dim strKey As String
    
    With Treeview1
        .Visible = False 
        .Nodes.Clear
        .Visible = True 
    End With
 
    lngFile = FreeFile
    Open "D:\Testing\TreeView.dat" For Binary As lngFile
    
    Get lngFile, , udtNodeData
    
    Do
        strParent = udtNodeData.ParentKey
        strKey = udtNodeData.Key
        
        If Len(Trim$(strParent)) > 0 Then
            Set objNode = Treeview1.Nodes.Add(Trim$(strParent), tvwChild, Trim$(strKey))
        Else
            Set objNode = Treeview1est.Nodes.Add(, , Trim$(strKey))
        End If
        
        objNode.Bold = udtNodeData.Bold
        objNode.Text = udtNodeData.Text
        objNode.ForeColor = udtNodeData.Color
        
        Get lngFile, , udtNodeData
    Loop Until EOF(lngFile)
    
    Close lngFile
 
End Sub

[ranma_at]

thanks,
i ll try these.

[Shawn N]

This isn't working for me. Nodes are saved correctly, but their relationships aren't.

[ranma_at]

this is working perfect, just be shure the nodes are unique :-)