# HierarchyViewModel > A hierarchy view model is a read-only filtering view of a HierarchyFlattened. ## Definition * **Type:** Class * **Namespace:** [Unity.Hierarchy](/engine/6000.6/script-reference/unity/hierarchy.md) * **Assembly:** UnityEngine.HierarchyCoreModule * **Implements:** [IDisposable](https://learn.microsoft.com/dotnet/api/system.idisposable) ```csharp public sealed class HierarchyViewModel : IDisposable ``` ## Constructors | Constructor | Description | | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------- | ---------------------------------------------------------------------------------------------------------------------------------------- | | [HierarchyViewModel(Unity.Hierarchy.HierarchyFlattened,Unity.Hierarchy.HierarchyNodeFlags)](/engine/6000.6/script-reference/unity/hierarchy/hierarchyviewmodel/ctor.md) | Constructs a new [HierarchyViewModel](/engine/6000.6/script-reference/unity/hierarchy/hierarchyviewmodel.md) from a flattened hierarchy. | ## Properties | Property | Description | | -------------------------------------------------------------------------------------------------- | ---------------------------------------------------------------------------------------------------------------- | | [Count](/engine/6000.6/script-reference/unity/hierarchy/hierarchyviewmodel/count.md) | The total number of nodes. | | [Filtering](/engine/6000.6/script-reference/unity/hierarchy/hierarchyviewmodel/filtering.md) | Whether the hierarchy view model is currently filtering nodes. | | [IsCreated](/engine/6000.6/script-reference/unity/hierarchy/hierarchyviewmodel/iscreated.md) | Whether this object is valid and uses memory. | | [this\[\]](/engine/6000.6/script-reference/unity/hierarchy/hierarchyviewmodel/item.md) | Gets the [HierarchyNode](/engine/6000.6/script-reference/unity/hierarchy/hierarchynode.md) at a specified index. | | [UpdateNeeded](/engine/6000.6/script-reference/unity/hierarchy/hierarchyviewmodel/updateneeded.md) | Whether the hierarchy view model requires an update. | | [Updating](/engine/6000.6/script-reference/unity/hierarchy/hierarchyviewmodel/updating.md) | Whether the hierarchy view model is currently updating. | ## Methods | Method | Description | | -------------------------------------------------------------------------------------------------------------------------------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | [AsReadOnlySpan](/engine/6000.6/script-reference/unity/hierarchy/hierarchyviewmodel/asreadonlyspan.md) | Returns a read-only span of all hierarchy nodes in the view model. | | [BeginFlagsChange](/engine/6000.6/script-reference/unity/hierarchy/hierarchyviewmodel/beginflagschange.md) | Begins a batch of flags changes. | | [ClearFlags](/engine/6000.6/script-reference/unity/hierarchy/hierarchyviewmodel/clearflags.md) | Clears the specified flags on the hierarchy node indices. | | [ClearFlagsRecursive](/engine/6000.6/script-reference/unity/hierarchy/hierarchyviewmodel/clearflagsrecursive.md) | Clears the specified flags recursively on the hierarchy nodes. | | [Contains](/engine/6000.6/script-reference/unity/hierarchy/hierarchyviewmodel/contains.md) | Determines if a specified node is in the hierarchy view model. | | [DestroyHandlerState](/engine/6000.6/script-reference/unity/hierarchy/hierarchyviewmodel/destroyhandlerstate.md) | Disposes and forgets the state a node type handler keeps for this view model. | | [Dispose](/engine/6000.6/script-reference/unity/hierarchy/hierarchyviewmodel/dispose.md) | Disposes this object and releases its memory. | | [DoesNotHaveFlags](/engine/6000.6/script-reference/unity/hierarchy/hierarchyviewmodel/doesnothaveflags.md) | Gets whether or not all of the specified flags are not set on the hierarchy node. | | [DoesNotHaveFlagsCount](/engine/6000.6/script-reference/unity/hierarchy/hierarchyviewmodel/doesnothaveflagscount.md) | Gets the number of nodes that do not have all of the specified flags set. | | [EndFlagsChange](/engine/6000.6/script-reference/unity/hierarchy/hierarchyviewmodel/endflagschange.md) | Ends a batch of flags changes. | | [EndFlagsChangeWithoutNotify](/engine/6000.6/script-reference/unity/hierarchy/hierarchyviewmodel/endflagschangewithoutnotify.md) | Ends a batch of flags changes without notifying listeners. | | [EnumerateNodesWithFlags](/engine/6000.6/script-reference/unity/hierarchy/hierarchyviewmodel/enumeratenodeswithflags.md) | Gets an enumerable of all hierarchy nodes that have all of the specified flags set. | | [EnumerateNodesWithoutFlags](/engine/6000.6/script-reference/unity/hierarchy/hierarchyviewmodel/enumeratenodeswithoutflags.md) | Gets an enumerable of all hierarchy nodes that do not have all of the specified flags set. | | [GetChild](/engine/6000.6/script-reference/unity/hierarchy/hierarchyviewmodel/getchild.md) | Gets the child node at the specified index of a hierarchy node. | | [GetChildIndex](/engine/6000.6/script-reference/unity/hierarchy/hierarchyviewmodel/getchildindex.md) | Gets the index of a hierarchy node in its parent's children list. | | [GetChildrenCount](/engine/6000.6/script-reference/unity/hierarchy/hierarchyviewmodel/getchildrencount.md) | Gets the number of child nodes that a hierarchy node has. | | [GetChildrenCountRecursive](/engine/6000.6/script-reference/unity/hierarchy/hierarchyviewmodel/getchildrencountrecursive.md) | Gets the number of child nodes that a hierarchy node has, including children of children. | | [GetDepth](/engine/6000.6/script-reference/unity/hierarchy/hierarchyviewmodel/getdepth.md) | Determines the depth of a node. | | [GetEnumerator](/engine/6000.6/script-reference/unity/hierarchy/hierarchyviewmodel/getenumerator.md) | Gets the [HierarchyNode](/engine/6000.6/script-reference/unity/hierarchy/hierarchynode.md) enumerator. | | [GetFlags](/engine/6000.6/script-reference/unity/hierarchy/hierarchyviewmodel/getflags.md) | Gets all the flags set on a given hierarchy node. | | [GetIndicesWithFlags](/engine/6000.6/script-reference/unity/hierarchy/hierarchyviewmodel/getindiceswithflags.md) | Gets the indices for all hierarchy nodes that have all of the specified flags set. | | [GetIndicesWithoutFlags](/engine/6000.6/script-reference/unity/hierarchy/hierarchyviewmodel/getindiceswithoutflags.md) | Gets the indices of all hierarchy nodes that do not have all of the specified flags set. | | [GetNextSibling](/engine/6000.6/script-reference/unity/hierarchy/hierarchyviewmodel/getnextsibling.md) | Gets the next sibling of a node. | | [GetNodesWithFlags](/engine/6000.6/script-reference/unity/hierarchy/hierarchyviewmodel/getnodeswithflags.md) | Gets all hierarchy nodes that have all of the specified flags set. | | [GetNodesWithoutFlags](/engine/6000.6/script-reference/unity/hierarchy/hierarchyviewmodel/getnodeswithoutflags.md) | Gets all hierarchy nodes that do not have all of the specified flags set. | | [GetNodeType](/engine/6000.6/script-reference/unity/hierarchy/hierarchyviewmodel/getnodetype.md) | Retrieve the hierarchy node type for the specified node. | | [GetNodeTypeHandlerBase](/engine/6000.6/script-reference/unity/hierarchy/hierarchyviewmodel/getnodetypehandlerbase.md) | Gets the node type handler instance for the specified node from this hierarchy view model. | | [GetOrCreateHandlerState](/engine/6000.6/script-reference/unity/hierarchy/hierarchyviewmodel/getorcreatehandlerstate.md) | Gets the state a node type handler keeps for this view model, creating it when there is none. | | [GetParent](/engine/6000.6/script-reference/unity/hierarchy/hierarchyviewmodel/getparent.md) | Gets the parent of a hierarchy node. | | [GetRoot](/engine/6000.6/script-reference/unity/hierarchy/hierarchyviewmodel/getroot.md) | Gets the root node of the hierarchy view model. | | [HasFlags](/engine/6000.6/script-reference/unity/hierarchy/hierarchyviewmodel/hasflags.md) | Gets whether or not all of the specified flags are set on the hierarchy node. | | [HasFlagsCount](/engine/6000.6/script-reference/unity/hierarchy/hierarchyviewmodel/hasflagscount.md) | Gets the number of nodes that have all of the specified flags set. | | [HasVisibleChildren](/engine/6000.6/script-reference/unity/hierarchy/hierarchyviewmodel/hasvisiblechildren.md) | Determines whether a hierarchy node has any visible direct children (children without the Hidden flag). | | [IndexOf](/engine/6000.6/script-reference/unity/hierarchy/hierarchyviewmodel/indexof.md) | Gets the zero-based index of a specified node. | | [SetFlags](/engine/6000.6/script-reference/unity/hierarchy/hierarchyviewmodel/setflags.md) | Sets the specified flags on the hierarchy node indices. | | [SetFlagsRecursive](/engine/6000.6/script-reference/unity/hierarchy/hierarchyviewmodel/setflagsrecursive.md) | Sets the specified flags recursively on the hierarchy nodes. | | [SetQuery](/engine/6000.6/script-reference/unity/hierarchy/hierarchyviewmodel/setquery.md) | Sets the search query. | | [SetRoot](/engine/6000.6/script-reference/unity/hierarchy/hierarchyviewmodel/setroot.md) | Sets the root of the hierarchy view model. | | [ToggleFlags](/engine/6000.6/script-reference/unity/hierarchy/hierarchyviewmodel/toggleflags.md) | Toggles the specified flags on the hierarchy node indices. | | [ToggleFlagsRecursive](/engine/6000.6/script-reference/unity/hierarchy/hierarchyviewmodel/toggleflagsrecursive.md) | Toggles the specified flags recursively on the hierarchy nodes. | | [TryGetHandlerState](/engine/6000.6/script-reference/unity/hierarchy/hierarchyviewmodel/trygethandlerstate.md) | Gets the state a node type handler keeps for this view model. | | [Update](/engine/6000.6/script-reference/unity/hierarchy/hierarchyviewmodel/update.md) | Updates the hierarchy view model and requests a rebuild of the list of [HierarchyNode](/engine/6000.6/script-reference/unity/hierarchy/hierarchynode.md) that filters the [HierarchyFlattened](/engine/6000.6/script-reference/unity/hierarchy/hierarchyflattened.md). | | [UpdateIncremental](/engine/6000.6/script-reference/unity/hierarchy/hierarchyviewmodel/updateincremental.md) | Updates the hierarchy view model incrementally. | | [UpdateIncrementalTimed](/engine/6000.6/script-reference/unity/hierarchy/hierarchyviewmodel/updateincrementaltimed.md) | Updates the hierarchy view model incrementally until a time limit is reached. | ## Events | Member | Description | | -------------------------------------------------------------------------------------------------- | ---------------------------------------------------------------- | | [FlagsChanged](/engine/6000.6/script-reference/unity/hierarchy/hierarchyviewmodel/flagschanged.md) | Event that is invoked when flags on hierarchy nodes are changed. | ## Structs | Struct | Description | | ----------------------------------------------------------------------------------------------------------------- | -------------------------------------------------------------------------------------------------------------------------------------------------- | | [HierarchyViewModel.Enumerator](/engine/6000.6/script-reference/unity/hierarchy/hierarchyviewmodel/enumerator.md) | An enumerator of [HierarchyNode](/engine/6000.6/script-reference/unity/hierarchy/hierarchynode.md). Enumerates and filters items at the same time. | ## Delegates | Delegate | Description | | --------------------------------------------------------------------------------------------------------------------------------------------- | ------------------------------------------------------------------- | | [HierarchyViewModel.FlagsChangedEventHandler](/engine/6000.6/script-reference/unity/hierarchy/hierarchyviewmodel/flagschangedeventhandler.md) | Delegate that is invoked when flags on hierarchy nodes are changed. |