/// <summary>
/// Returns last sibling of given item, or default value if there are no siblings.
/// </summary>
/// <param name="collection">Sequence to filter. </param>
/// <param name="item">Item to find siblings for. </param>
/// <typeparam name="TResult">Type of sequence containing item siblings. Should implement <see cref="IHasTreeEntry"/>. </typeparam>
/// <typeparam name="TFilter">Type of referenced item to use in query. Should implement <see cref="IHasTreeEntry"/>. </typeparam>
/// <returns>last sibling of given item or default value if there are no siblings. </returns>
public static TResult LastSiblingOrDefault <TResult, TFilter>(this IQueryable <TResult> collection, TFilter item)
where TResult : IHasTreeEntry
where TFilter : IHasTreeEntry
{
return(collection.Where(i => i.TreeEntry, NestedIntervalsSpec.SiblingsAfter(item.TreeEntry, true))
.OrderBy(i => i.TreeEntry.Nv).LastOrDefault());
}
/// <summary>
/// Filter a sequence of values to return sibling elements of given item, positioned after it.
/// Item considered as sibling if it's children of same parent item.
/// </summary>
/// <param name="collection">Sequence to filter. </param>
/// <param name="item">Item to find siblings for. </param>
/// <param name="includeSelf">Whether or not to include referenced item itself in list of siblings. false by default. </param>
/// <typeparam name="TResult">Type of sequence containing item siblings. Should implement <see cref="IHasTreeEntry"/>. </typeparam>
/// <typeparam name="TFilter">Type of referenced item to use in query. Should implement <see cref="IHasTreeEntry"/>. </typeparam>
/// <returns>Sequence of sibling items of given item, positioned after it. </returns>
public static IQueryable <TResult> SiblingsAfter <TResult, TFilter>(
this IQueryable <TResult> collection,
TFilter item,
bool includeSelf = false)
where TResult : IHasTreeEntry
where TFilter : IHasTreeEntry
{
return(collection.Where(i => i.TreeEntry, NestedIntervalsSpec.SiblingsAfter(item.TreeEntry, includeSelf)));
}