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. :confused: 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.