Save and Load XML in Windows Forms TreeView

8 Jul 20268 minutes to read

TreeViewAdv does not have a direct option to load or save from an XML file. The section below demonstrates how to load and save a TreeViewAdv from XML.

C#

/// <summary>

/// To load TreeViewAdv from XML File

/// </summary>

private void LoadTreeViewAdvXML()
{
    XmlDocument xDoc = new XmlDocument();
    xDoc.Load("TreeView.xml");
    treeViewAdv1.Nodes.Clear();
    treeViewAdv1.Nodes.Add(new TreeNodeAdv(xDoc.DocumentElement.Name));
    TreeNodeAdv tNode = new TreeNodeAdv();
    tNode = (TreeNodeAdv)treeViewAdv1.Nodes[0];
    LoadFromXML(xDoc.DocumentElement, tNode);
    treeViewAdv1.ExpandAll();
}

/// <summary>
/// Helper that returns the value of the "name" attribute on the supplied XML node, or null if the attribute is missing.
/// </summary>
private string GetAttributeText(XmlNode xmlNode, string attributeName)
{
    if (xmlNode.Attributes != null && xmlNode.Attributes[attributeName] != null)
    {
        return xmlNode.Attributes[attributeName].Value;
    }
    return null;
}
private void LoadFromXML(XmlNode xmlNode, TreeNodeAdv treeNode)
{
    XmlNode xNode;
    TreeNodeAdv tNode;
    XmlNodeList xNodeList;
    if (xmlNode.HasChildNodes) 
    {
        xNodeList = xmlNode.ChildNodes;
        for (int x = 0; x <= xNodeList.Count - 1; x++)
        {
            xNode = xmlNode.ChildNodes[x];
            treeNode.Nodes.Add(new TreeNodeAdv(xNode.Name));
            tNode = treeNode.Nodes[x];
            LoadFromXML(xNode, tNode);
        }
    }
    else
    {
        //Retrieve child nodes of root node
        string text = GetAttributeText(xmlNode, "name");
        if (string.IsNullOrEmpty(text))
                    text = (xmlNode.OuterXml).Trim();
        if (treeNode.Text != text)
                    treeNode.Text = text;
        treeNode.Nodes.Clear();
    }
}
       
/// <summary>
        /// To write details in XML Elements
        /// </summary>
        private XmlTextWriter XmlTextWriter;

        /// <summary>
        /// To save TreeViewAdv node information to XML File
public void ExportToXML(TreeViewAdv tree, string filename)
{
    XmlTextWriter = new XmlTextWriter(filename, System.Text.Encoding.UTF8);
    XmlTextWriter.WriteStartDocument();
    XmlTextWriter.WriteStartElement(treeViewAdv1.Nodes[0].Text);
    foreach (TreeNodeAdv node in tree.Nodes)
    {
        SaveToXML(node.Nodes);
    }
    XmlTextWriter.WriteEndElement();
    XmlTextWriter.Close();
}

/// <summary>

/// Iterate function helps to save TreeNodeAdv information to XML

/// </summary>
private void SaveToXML(TreeNodeAdvCollection menu)
{
    foreach (TreeNodeAdv node in menu)
    {
        if (node.Nodes.Count > 0)
        {
            XmlTextWriter.WriteStartElement(node.Text);
            SaveToXML(node.Nodes);
            XmlTextWriter.WriteEndElement();
        }
        else
        {
            XmlTextWriter.WriteString(node.Text);
        }
    }
}

VB.NET

''' <summary>

''' To load TreeViewAdv from XML File

''' </summary>
Private Sub LoadTreeViewAdvXML()
    Dim xDoc As New XmlDocument()
    xDoc.Load("TreeView.xml")
    treeViewAdv1.Nodes.Clear()
    treeViewAdv1.Nodes.Add(New TreeNodeAdv(xDoc.DocumentElement.Name))
    Dim tNode As New TreeNodeAdv()
    tNode = CType(treeViewAdv1.Nodes(0), TreeNodeAdv)
    LoadFromXML(xDoc.DocumentElement, tNode)
    treeViewAdv1.ExpandAll()
End Sub

''' <summary>
''' Helper that returns the value of the named attribute on the supplied XML node, or Nothing if the attribute is missing.
''' </summary>
Private Function GetAttributeText(ByVal xmlNode As XmlNode, ByVal attributeName As String) As String
    If xmlNode.Attributes IsNot Nothing AndAlso xmlNode.Attributes(attributeName) IsNot Nothing Then
        Return xmlNode.Attributes(attributeName).Value
    End If
    Return Nothing
End Function
Private Sub LoadFromXML(ByVal xmlNode As XmlNode, ByVal treeNode As TreeNodeAdv)
Dim xNode As XmlNode
Dim tNode As TreeNodeAdv
Dim xNodeList As XmlNodeList
If xmlNode.HasChildNodes Then
xNodeList = xmlNode.ChildNodes
For x As Integer = 0 To xNodeList.Count - 1
xNode = xmlNode.ChildNodes(x)
treeNode.Nodes.Add(New TreeNodeAdv(xNode.Name))
tNode = treeNode.Nodes(x)
LoadFromXML(xNode, tNode)
Next x
Else
Dim text As String = GetAttributeText(xmlNode, "name")
If String.IsNullOrEmpty(text) Then text = (xmlNode.OuterXml).Trim()
If treeNode.Text IsNot text Then treeNode.Text = text
treeNode.Nodes.Clear()
End If End Sub

''' <summary>

''' To write details in XML Elements

''' </summary>
Private XmlTextWriter As XmlTextWriter

''' <summary>

''' To save TreeViewAdv node information to XML File

''' </summary>
Public Sub ExportToXML(ByVal tree As TreeViewAdv, ByVal filename As String)
XmlTextWriter = New XmlTextWriter(filename, System.Text.Encoding.UTF8)
XmlTextWriter.WriteStartDocument()
XmlTextWriter.WriteStartElement(treeViewAdv1.Nodes(0).Text)
For Each node As TreeNodeAdv In tree.Nodes
SaveToXML(node.Nodes)
Next node
XmlTextWriter.WriteEndElement()
XmlTextWriter.Close()
End Sub

''' <summary>

''' Iterate function helps to save TreeNodeAdv information to XML

''' </summary>

Private Sub SaveToXML(ByVal menu As TreeNodeAdvCollection)
For Each node As TreeNodeAdv In menu
If node.Nodes.Count > 0 Then
XmlTextWriter.WriteStartElement(node.Text)
SaveToXML(node.Nodes)
XmlTextWriter.WriteEndElement()
Else
XmlTextWriter.WriteString(node.Text)
End If
Next node
End Sub

You can download the sample here.