[DXCategory("VirtualTree")]
public event VirtualTreeSetCellValueEventHandler VirtualTreeSetCellValue

<DXCategory("VirtualTree")>
Public Event VirtualTreeSetCellValue As VirtualTreeSetCellValueEventHandler

navigationTreeList.VirtualTreeGetChildNodes += OnNavigationTreeListGetChildNodes;
navigationTreeList.VirtualTreeGetCellValue += OnNavigationTreeListGetCellValue;
//...
void OnNavigationTreeListGetChildNodes(object sender, VirtualTreeGetChildNodesInfo e) {
    Cursor current = Cursor.Current;
    Cursor.Current = Cursors.WaitCursor;
    e.Children = ((Item)e.Node).GetDirectories();
    Cursor.Current = current;
}

void OnNavigationTreeListGetCellValue(object sender, VirtualTreeGetCellValueInfo e) {
    e.CellData = ((Item)e.Node).DisplayName;
}

//...
public abstract class Item : IFileImage {
    //...
    public string DisplayName {get; private set;}
    public abstract List<Item> GetDirectories();
}

AddHandler Me.navigationTreeList.VirtualTreeGetChildNodes, AddressOf Me.OnNavigationTreeListGetChildNodes
AddHandler Me.navigationTreeList.VirtualTreeGetCellValue, AddressOf Me.OnNavigationTreeListGetCellValue
'...
Private Sub OnNavigationTreeListGetChildNodes(ByVal sender As Object, ByVal e As DevExpress.XtraTreeList.VirtualTreeGetChildNodesInfo)
    Dim current As System.Windows.Forms.Cursor = System.Windows.Forms.Cursor.Current
    System.Windows.Forms.Cursor.Current = System.Windows.Forms.Cursors.WaitCursor
    e.Children = CType(e.Node, DevExpress.XtraTreeList.Demos.Item).GetDirectories()
    System.Windows.Forms.Cursor.Current = current
End Sub

Private Sub OnNavigationTreeListGetCellValue(ByVal sender As Object, ByVal e As DevExpress.XtraTreeList.VirtualTreeGetCellValueInfo)
    e.CellData = CType(e.Node, DevExpress.XtraTreeList.Demos.Item).DisplayName
End Sub

Public MustInherit Class Item
    Implements DevExpress.XtraTreeList.Demos.IFileImage
    '...
    Private _DisplayName As String, _Name As String, _FullName As String
    Public MustOverride Function GetDirectories() As List(Of DevExpress.XtraTreeList.Demos.Item)
End Class

using DevExpress.XtraTreeList;

void OnVirtualTreeSetCellValue(object sender, VirtualTreeSetCellValueInfo e) {
    ((Item)e.Node).DisplayName = e.NewCellData.ToString();
}

Imports DevExpress.XtraTreeList

Private Sub OnVirtualTreeSetCellValue(ByVal sender As Object, ByVal e As VirtualTreeSetCellValueInfo)
    CType(e.Node, Item).DisplayName = e.NewCellData.ToString()
End Sub