Saving/Opening Tree Views

[mntlnstituteflr]

Hello,

I am making an application again and I have come to a problem. I can not figure out how to make a Tree View open and save their data as a custom file format. What I have tried is...

    Private Sub SaveAsToolStripMenuItem_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles SaveAsToolStripMenuItem.Click
        If SaveFileDialog1.ShowDialog() = Windows.Forms.DialogResult.OK Then
               TreeView1.SaveFile(SaveFileDialog1.FileName)
        End If
    End Sub

That doesn't work and I have tried other codings such as converting it to plain text, which obviously didn't work either...

Can you help me?

Patrick

 

[snarfblam]

You will have to iterate through the tree nodes and save them yourself. Intellisense or MSDN will make it adequately clear that there is no built-in method to save the contents of a treeview, as you will find with the majority of controls.

Sub SaveTree
    'You may need to add/change parameters
    Dim MyFileStream As New FileStream("C:\MyFile.extension") 
    Dim MyWriter As New BinaryWriter(MyFileStream)
    
    MyWriter.Write(MyTree.Nodes.Count)
    For I As Integer = 0 To MyTree.Nodes.Count - 1
        SaveNode(MyWriter, MyTree.Nodes(i))
    Next I
End Sub
 
Sub SaveNode(BinaryWriter b, TreeNode t)
    b.Write(t.Text)
    b.Write(t.Nodes.Count)
    For I As Integer = 0 To t.Nodes.Count - 1
        SaveNode(b, t.Nodes(i))
    Next
End Sub
    
Sub LoadTree
    'You may need to add/change parameters
    Dim MyFileStream As New FileStream("C:\MyFile.extension") 
    Dim MyReader As New BinaryReader(MyFileStream)
    
    Dim NodeCount As Integer = MyReader.ReadInt32()
    For I As Integer = 0 To NodeCount - 1
        MyTree.Nodes.Add(LoadNode(MyReader))
    Next I
End Sub
 
Function LoadNode(BinaryReader b, TreeNode t) As TreeNode
    Dim Text As String = b.ReadString()
    Dim NodeCount As Intger = b.ReadInt32()
 
    Dim ResultNode As New TreeNode(Text)

    For I As Integer = 0 To NodeCount
        ResultNode.Nodes.Add(LoadNode(b))
    Next
    
    Return ResultNode
End Sub

That code most likely won't compile or run, but it demonstrates the basic process of saving the contents of a hierarchal structure using recursion.