HierarchyId

HierarchyId class provides tools for operating with identificators of objects combined into hierarchical structure. The idea of hierarchical id becomes helpful when working of objects combined into hierarchical structures. It could be organization departments for example.

Instance of HierarchyId represents hierarchical identificator for node and contain ids of all ancestors for current node. For example it could be: "/10/38/94/", which means that current node has id=94, its parent id is 38 and grandparent id is 10.

Methods of this class allows getting ancestor of needed level, check if current node is descendant of some other node, move nodes in hierarchy etc.

All methods are described below:

Methods

Method name	Return type	Description
Constructor	HierarchyId	Initializes a new instance of the HierarchyId class that holds data about provided nodes ids.
GetNode	int	Gets last node in current branch of hierarchy
IsDescendantOf	bool	Determines whether current node is descendant of specified node.
GetAncestor	HierarchyId	Gets ancestor of current node n-levels higher than itself.
GetDescendant	HierarchyId	Gets hierarchical id for direct descendant of current node with regular id specified.
GetLevel	int	Gets level in hierarchy for current node.
Move	-	Moves current node from its current ancestor to new one.
ToString	string	Creates string representation of current HierarchyId.
Parse	HierarchyId	Creates HierarchyId instance from its string representation.

Basic usage

// Create hierarchical id from ids of items in brunch of hierarchy
var hierarchyId = new HierarchyId(new int[] { 1, 2, 3, 4, 5 });

// Get string representation
var strId = hierarchyId.ToString(); // "/1/2/3/4/5/"

// Get current node id
var currentId = hierarchyId.GetNode(); // 5

// Check hierarchical relations
var f1 = hierarchyId.IsDescendantOf(3); // true
var f2 = hierarchyId.IsDescendantOf(6); // false

// Get ancestor
var a1 = hierarchyId.GetAncestor(1); // "/1/2/3/4/"
var a2 = hierarchyId.GetAncestor(3); // "/1/2/"

// Get hierarchical id for descendant of current node
var d = hierarchyId.GetDescendant(6); // "/1/2/3/4/5/6/"

// Get level of current node
var level = hierarchyId.GetLevel(); // 5

// Move current node to another brunch
var newHierarchyId = new HierarchyId(new int[] { 11, 12, 13, 14, 15 });
var ancestor1 = new HierarchyId(new int[] { 11, 12, 13 });
var ancestor2 = new HierarchyId(new int[] { 21, 22 });
newHierarchyId.Move(ancestor1, ancestor2); // results in "/21/22/14/15/"