/// <summary>
/// Get the direct children of a <see cref="Hierarchy"/> filtered by type and an optional filter delegate. It stores them in a List parameter
/// to avoid garbage allocations.
/// </summary>
/// <typeparam name="TElement">The type of the child elements</typeparam>
/// <param name="hierarchy">The parent hierarchy</param>
/// <param name="results">A List to store the results</param>
/// <param name="filter">An optional filter callback</param>
public static void GetChildren <TElement>(this Hierarchy hierarchy, List <TElement> results, Func <TElement, bool> filter = null)
where TElement : VisualElement
{
for (int i = 0; i < hierarchy.childCount; i++)
{
if (hierarchy[i] is TElement element && (filter == null || filter(element)))
{
results.Add(element);
}
}
}
/// <summary>
/// Execute an action on all direct children with a certain type.
/// </summary>
/// <typeparam name="TElement">The type of the child elements.</typeparam>
/// <param name="hierarchy">The parent hierarchy.</param>
/// <param name="action">The action to execute.</param>
public static void ForEachChild <TElement>(this Hierarchy hierarchy, Action <TElement> action)
where TElement : VisualElement
{
for (int i = 0; i < hierarchy.childCount; i++)
{
if (hierarchy[i] is TElement element)
{
action(element);
}
}
}
/// <summary>
/// Get the first direct child with a certain type that passes an optional filter delegate.
/// </summary>
/// <typeparam name="TElement">The type of the child</typeparam>
/// <param name="hierarchy">The parent element</param>
/// <param name="filter">An optional filter callback</param>
/// <returns>A child that satisfies conditions or null.</returns>
public static TElement GetFirstChild <TElement>(this Hierarchy hierarchy, Func <TElement, bool> filter = null)
where TElement : VisualElement
{
for (int i = 0; i < hierarchy.childCount; i++)
{
if (hierarchy[i] is TElement element && (filter == null || filter(element)))
{
return(element);
}
}
return(null);
}
