Iterate Through Nodes

  • 7 minutes to read

The Node Iterator allows you to traverse through the nodes without writing recursive code. Nodes are visited one by one starting from a specified node down to the last node contained within a tree.

The image below illustrates the sequence in which nodes are processed.

treelistNodeIteration

To iterate through the nodes, do the following.

Example: How to Iterate Through All Visible Nodes

This example shows how to traverse through all visible nodes to expand those nodes that have more than four child nodes. Nodes that have less than four child nodes are collapsed.

<Window xmlns:dxg="clr-namespace:DevExpress.Xpf.Grid;assembly=DevExpress.Xpf.Grid.v11.1"  x:Class="WpfApplication1.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:dx="http://schemas.devexpress.com/winfx/2008/xaml/core"
        dx:ThemeManager.ThemeName="Office2007Black"
        Title="MainWindow" Height="350" Width="525">
    <Grid>
        <dxg:GridControl Name="grid" Loaded="grid_Loaded">
            <dxg:GridControl.Columns>
                <dxg:GridColumn FieldName="Name"/>
                <dxg:GridColumn FieldName="Department"/>
                <dxg:GridColumn FieldName="Position"/>
            </dxg:GridControl.Columns>
            <dxg:GridControl.View>
                <dxg:TreeListView Name="treeListView" AutoWidth="True"
                                  KeyFieldName="ID" ParentFieldName="ParentID"/>
            </dxg:GridControl.View>
        </dxg:GridControl>
    </Grid>
</Window>
using System;
using System.Collections.Generic;

public class Employee {
    public int ID { get; set; }
    public int ParentID { get; set; }
    public string Name { get; set; }
    public string Position { get; set; }
    public string Department { get; set; }
}

public static class Stuff {
    public static List<Employee> GetStuff() {
        List<Employee> stuff = new List<Employee>();
        stuff.Add(new Employee() { ID = 1, ParentID = 0, Name = "Gregory S. Price", Department = "", Position = "President" });
        stuff.Add(new Employee() { ID = 2, ParentID = 1, Name = "Irma R. Marshall", Department = "Marketing", Position = "Vice President" });
        stuff.Add(new Employee() { ID = 3, ParentID = 1, Name = "John C. Powell", Department = "Operations", Position = "Vice President" });
        stuff.Add(new Employee() { ID = 4, ParentID = 1, Name = "Christian P. Laclair", Department = "Production", Position = "Vice President" });
        stuff.Add(new Employee() { ID = 5, ParentID = 1, Name = "Karen J. Kelly", Department = "Finance", Position = "Vice President" });

        stuff.Add(new Employee() { ID = 6, ParentID = 2, Name = "Brian C. Cowling", Department = "Marketing", Position = "Manager" });
        stuff.Add(new Employee() { ID = 7, ParentID = 2, Name = "Thomas C. Dawson", Department = "Marketing", Position = "Manager" });
        stuff.Add(new Employee() { ID = 8, ParentID = 2, Name = "Angel M. Wilson", Department = "Marketing", Position = "Manager" });
        stuff.Add(new Employee() { ID = 9, ParentID = 2, Name = "Bryan R. Henderson", Department = "Marketing", Position = "Manager" });

        stuff.Add(new Employee() { ID = 10, ParentID = 3, Name = "Harold S. Brandes", Department = "Operations", Position = "Manager" });
        stuff.Add(new Employee() { ID = 11, ParentID = 3, Name = "Michael S. Blevins", Department = "Operations", Position = "Manager" });
        stuff.Add(new Employee() { ID = 12, ParentID = 3, Name = "Jan K. Sisk", Department = "Operations", Position = "Manager" });
        stuff.Add(new Employee() { ID = 13, ParentID = 3, Name = "Sidney L. Holder", Department = "Operations", Position = "Manager" });

        stuff.Add(new Employee() { ID = 14, ParentID = 4, Name = "James L. Kelsey", Department = "Production", Position = "Manager" });
        stuff.Add(new Employee() { ID = 15, ParentID = 4, Name = "Howard M. Carpenter", Department = "Production", Position = "Manager" });
        stuff.Add(new Employee() { ID = 16, ParentID = 4, Name = "Jennifer T. Tapia", Department = "Production", Position = "Manager" });

        stuff.Add(new Employee() { ID = 17, ParentID = 5, Name = "Judith P. Underhill", Department = "Finance", Position = "Manager" });
        stuff.Add(new Employee() { ID = 18, ParentID = 5, Name = "Russell E. Belton", Department = "Finance", Position = "Manager" });
        return stuff;
    }
}
using System.Windows;
using DevExpress.Xpf.Grid;

namespace WpfApplication1 {
    /// <summary>
    /// Interaction logic for MainWindow.xaml
    /// </summary>
    public partial class MainWindow : Window {
        public MainWindow() {
            InitializeComponent();
            grid.ItemsSource = Stuff.GetStuff();
        }

        private void SmartExpandNodes(int minChildCount) {
            TreeListNodeIterator nodeIterator = new TreeListNodeIterator(treeListView.Nodes, true);
            while (nodeIterator.MoveNext())
                nodeIterator.Current.IsExpanded = nodeIterator.Current.Nodes.Count >= minChildCount;
        }

        private void grid_Loaded(object sender, RoutedEventArgs e) {
            SmartExpandNodes(4);
        }
    }
}