How do I save/load the contents of a Treeview to a file?
I have found several good examples written i VB6, but not a single one for
VB.NET.
Please help.
The following uses a couple of strucures to represent the Treeview in
it's simplest form and then serialization to persist the data to file:
<Code>
<Serializable()> Public Structure TreeViewData
Public Nodes() As TreeNodeData
Public Sub New(ByVal treeview As TreeView)
If treeview.Nodes.Count = 0 Then Exit Sub
ReDim Nodes(treeview.Nodes.Count - 1)
For i As Integer = 0 To treeview.Nodes.Count - 1
Nodes(i) = New TreeNodeData(treeview.Nodes(i))
Next
End Sub
Public Sub PopulateTree(ByVal treeview As TreeView)
If Me.Nodes Is Nothing OrElse Me.Nodes.Length = 0 Then Exit
Sub
For i As Integer = 0 To Me.Nodes.Length - 1
treeview.Nodes.Add(Me.Nodes(i).ToTreeNode)
Next
End Sub
End Structure
<Serializable()> Public Structure TreeNodeData
Public Text As String
Public ImageIndex As Integer
Public SelectedImageIndex As Integer
Public Nodes() As TreeNodeData
Public Sub New(ByVal node As TreeNode)
Me.Text = node.Text
Me.ImageIndex = node.ImageIndex
Me.SelectedImageIndex = node.SelectedImageIndex
If node.Nodes.Count = 0 Then Exit Sub
ReDim Nodes(node.Nodes.Count - 1)
For i As Integer = 0 To node.Nodes.Count - 1
Nodes(i) = New TreeNodeData(node.Nodes(i))
Next
End Sub
Public Function ToTreeNode() As TreeNode
ToTreeNode = New TreeNode(Me.Text, Me.ImageIndex,
Me.SelectedImageIndex)
If Me.Nodes Is Nothing OrElse Me.Nodes.Length = 0 Then Exit
Function
For i As Integer = 0 To Me.Nodes.Length - 1
ToTreeNode.Nodes.Add(Me.Nodes(i).ToTreeNode)
Next
End Function
End Structure
</Code>
Then to use it:
<Code>
Private SubLoadButton_Click(ByVal sender As System.Object, ByVal e
As System.EventArgs) Handles Button3.Click
Dim ser As New
System.Xml.Serialization.XmlSerializer(GetType(TreeViewData))
Dim file As New System.IO.FileStream("C:\Temp\TreeView.xml",
IO.FileMode.OpenOrCreate)
Dim writer As New System.Xml.XmlTextWriter(file, Nothing)
ser.Serialize(writer, New TreeViewData(TreeView1))
writer.Close()
file.Close()
file = Nothing
End Sub
Private Sub Button4_Click(ByVal sender As System.Object, ByVal e
As System.EventArgs) Handles Button4.Click
Dim ser As New
System.Xml.Serialization.XmlSerializer(GetType(TreeViewData))
Dim file As New System.IO.FileStream("C:\Temp\TreeView.xml",
IO.FileMode.Open)
Dim reader As New System.Xml.XmlTextReader(file)
Dim treeData As TreeViewData = CType(ser.Deserialize(reader),
TreeViewData)
treeData.PopulateTree(TreeView1)
reader.Close()
file.Close()
file = Nothing
End Sub
</Code>
Hope this helps
Blu.
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