Gets or sets whether the current item is considered and presented as a summary node even when it doesn't have child items. When a node is set as a virtual summary its initial expansion state is set to collapsed, and the VirtualSummaryInitiallyExpanded event will occur when it will be expanded for the first time, allowing child item initialization (lazy loading). This is a dependency property.

public bool IsVirtualSummary { get; set; }

Public Property IsVirtualSummary As Boolean