How To Sort All Nodes in a .NET TreeView Control?

By default, nodes in the TreeView control are not sorted. To sort all nodes in a .NET TreeView control, you have to set TreeView.TreeViewNodeSorter property to perform a custom sort of the TreeView nodes.

The following code example demonstrates how to use the TreeViewNodeSorter property to sort nodes from smallest to largest. To run this example, paste the following code into a Windows Form and call InitializeTreeView1 from the form's constructor or Load event handler.

// Declare the TreeView.
private TreeView treeView1;
private TextBox textBox1;
private Button button1;

private void InitializeTreeView1()
{
    // Create the TreeView
    treeView1 = new TreeView();
    treeView1.Size = new Size(200, 200);

    // Create the button and set some basic properties.
    button1 = new Button();
    button1.Location = new Point(205, 138);
    button1.Text = "Set Sorter";

    // Handle the click event for the button.
    button1.Click += new EventHandler(button1_Click);

    // Create the root nodes.
    TreeNode docNode = new TreeNode("Documents");
    TreeNode spreadSheetNode = new TreeNode("Spreadsheets");

    // Add some additional nodes.
    spreadSheetNode.Nodes.Add("payroll.xls");
    spreadSheetNode.Nodes.Add("checking.xls");
    spreadSheetNode.Nodes.Add("tracking.xls");
    docNode.Nodes.Add("phoneList.doc");
    docNode.Nodes.Add("resume.doc");

    // Add the root nodes to the TreeView.
    treeView1.Nodes.Add(spreadSheetNode);
    treeView1.Nodes.Add(docNode);

    // Add the TreeView to the form.
    Controls.Add(treeView1);
    Controls.Add(button1);
}

// Set the TreeViewNodeSorter property to a new instance
// of the custom sorter.
private void button1_Click(object sender, EventArgs e)
{
    treeView1.TreeViewNodeSorter = new NodeSorter();
}

// Create a node sorter that implements the IComparer interface.
public class NodeSorter : IComparer
{
    public int Compare(object x, object y)
    {
        TreeNode tx = x as TreeNode;
        TreeNode ty = y as TreeNode;

        return string.Compare(tx.Text, ty.Text);
    }
}