public class TreeListColumnDisplayTextEventArgs :
    EventArgs

Public Class TreeListColumnDisplayTextEventArgs
    Inherits EventArgs

protected void Page_Load(object sender, EventArgs e)
{
    TreeList.SettingsBehavior.SortMode = cbSortByDisplayText.Checked ? ColumnSortMode.DisplayText : ColumnSortMode.Value;
    TreeList.DataSource = GetItems();
    TreeList.DataBind();
}

public List<NodeItem> GetItems()
{
    return new List<NodeItem>() {
        new NodeItem(1, 0, 2),
            new NodeItem(2, 1, 3),
            new NodeItem(3, 1, 1),
            new NodeItem(4, 1, 4),
            new NodeItem(5, 1, 2),
            new NodeItem(6, 1, 3),
                new NodeItem(7, 3, 3),
                new NodeItem(8, 3, 6),
                new NodeItem(9, 3, 5),
        new NodeItem(10, 0, 4),
        new NodeItem(11, 0, 3)
    };
}
public class NodeItem
{
    public NodeItem(int id, int parentID, int categoryID) {
        ID = id;
        ParentID = parentID;
        CategoryID = categoryID;
    }
    public int ID { get; set; }
    public int ParentID { get; set; }
    public int CategoryID { get; set; }
}

Dictionary<int, Color> colors = new Dictionary<int, Color>() {
    { 0, Color.LightCoral },
    { 1, Color.LightCyan },
    { 3, Color.LightGreen },
};

protected void TreeList_HtmlRowPrepared(object sender, DevExpress.Web.ASPxTreeList.TreeListHtmlRowEventArgs e)
{
    e.Row.BackColor = colors[Convert.ToInt32(e.GetValue(TreeList.ParentFieldName))];
}
protected void TreeList_CustomColumnDisplayText(object sender, DevExpress.Web.ASPxTreeList.TreeListColumnDisplayTextEventArgs e)
{
    if (e.Column.FieldName == "ID")
        e.DisplayText = Convert.ToInt32(e.Value) % 2 == 0 ? "DisplayText=Text1; value=" + e.Value : "DisplayText=Text2; value=" + e.Value;        
}

<dx:ASPxCheckBox runat="server" ID="cbSortByDisplayText" AutoPostBack="true" Text="Sort by Display text" />
<dx:ASPxTreeList runat="server" ID="TreeList" KeyFieldName="ID" ParentFieldName="ParentID" Width="500" OnCustomColumnDisplayText="TreeList_CustomColumnDisplayText" OnHtmlRowPrepared="TreeList_HtmlRowPrepared">
    <Columns>
        <dx:TreeListDataColumn FieldName="ID" />
        <dx:TreeListComboBoxColumn FieldName="CategoryID">
        </dx:TreeListComboBoxColumn>
    </Columns>
    <SettingsBehavior AutoExpandAllNodes="true" />
</dx:ASPxTreeList>