# GetNodeTypeHandler

> Gets a HierarchyNodeTypeHandler instance from this hierarchy.

## Definition

* **Type:** Method
* **Namespace:** [Unity.Hierarchy](/engine/6000.7/script-reference/unity/hierarchy.md)
* **Assembly:** UnityEngine.HierarchyModule

## GetNodeTypeHandler\<T>(Hierarchy)

Gets a [HierarchyNodeTypeHandler](/engine/6000.7/script-reference/unity/hierarchy/hierarchynodetypehandler.md) instance from this hierarchy.

```csharp
public static T GetNodeTypeHandler<T>(this Hierarchy hierarchy) where T : HierarchyNodeTypeHandler
```

### Parameters

**** (\[Hierarchy]\(/engine/6000.7/script-reference/unity/hierarchy/hierarchy)):&#x20;

### Returns

| Type | Description                                                                                                  |
| ---- | ------------------------------------------------------------------------------------------------------------ |
| T    | The [HierarchyNodeTypeHandler](/engine/6000.7/script-reference/unity/hierarchy/hierarchynodetypehandler.md). |

### Remarks

Use this method to retrieve a specific [HierarchyNodeTypeHandler](/engine/6000.7/script-reference/unity/hierarchy/hierarchynodetypehandler.md) when you know the exact type at compile time.

## GetNodeTypeHandler(Hierarchy, HierarchyNode)

Gets the [HierarchyNodeTypeHandler](/engine/6000.7/script-reference/unity/hierarchy/hierarchynodetypehandler.md) instance for the specified node from this hierarchy.

```csharp
public static HierarchyNodeTypeHandler GetNodeTypeHandler(this Hierarchy hierarchy, in HierarchyNode node)
```

### Parameters

**** (\[Hierarchy]\(/engine/6000.7/script-reference/unity/hierarchy/hierarchy)): The [Hierarchy](/engine/6000.7/script-reference/unity/hierarchy/hierarchy.md) to get the [HierarchyNodeTypeHandler](/engine/6000.7/script-reference/unity/hierarchy/hierarchynodetypehandler.md) from.**** (\[HierarchyNode]\(/engine/6000.7/script-reference/unity/hierarchy/hierarchynode)): The [HierarchyNode](/engine/6000.7/script-reference/unity/hierarchy/hierarchynode.md) to get the [HierarchyNodeTypeHandler](/engine/6000.7/script-reference/unity/hierarchy/hierarchynodetypehandler.md) for.

### Returns

| Type                                                                                                    | Description                                                                                                  |
| ------------------------------------------------------------------------------------------------------- | ------------------------------------------------------------------------------------------------------------ |
| [HierarchyNodeTypeHandler](/engine/6000.7/script-reference/unity/hierarchy/hierarchynodetypehandler.md) | The [HierarchyNodeTypeHandler](/engine/6000.7/script-reference/unity/hierarchy/hierarchynodetypehandler.md). |

### Remarks

Use this method to retrieve a specific [HierarchyNodeTypeHandler](/engine/6000.7/script-reference/unity/hierarchy/hierarchynodetypehandler.md) instance from a specific [HierarchyNode](/engine/6000.7/script-reference/unity/hierarchy/hierarchynode.md).

## GetNodeTypeHandler(HierarchyViewModel, HierarchyNode)

Get the node type handler instance for the specified node from this hierarchy.

```csharp
public static HierarchyNodeTypeHandler GetNodeTypeHandler(this HierarchyViewModel hierarchyViewModel, in HierarchyNode node)
```

### Parameters

**** (\[HierarchyViewModel]\(/engine/6000.7/script-reference/unity/hierarchy/hierarchyviewmodel)): The hierarchy view model.**** (\[HierarchyNode]\(/engine/6000.7/script-reference/unity/hierarchy/hierarchynode)): The hierarchy node.

### Returns

| Type                                                                                                    | Description                      |
| ------------------------------------------------------------------------------------------------------- | -------------------------------- |
| [HierarchyNodeTypeHandler](/engine/6000.7/script-reference/unity/hierarchy/hierarchynodetypehandler.md) | The hierarchy node type handler. |

### Remarks

The following example adds context menu actions to the Hierarchy window to add or remove a specific component from a GameObject. The actions appear in the **Hierarchy Samples** submenu of the context menu. The example uses `GetNodeTypeHandler` to check whether each selected node is handled by a `HierarchyGameObjectHandler` and filters out nodes of other types.

The example requires a custom MonoBehaviour script called `Enemy.cs`.

To use this example:

1. Save the script in a folder called `Assets/Editor/CustomContextMenuAction`. Scripts in an `Editor` folder can use the Hierarchy module API without additional setup. If you save the script outside of an `Editor` folder, you must enable the Hierarchy built-in module in the **Package Manager** window, which also adds the module to your Player builds.
2. Save the `Enemy.cs` script outside of an `Editor` folder, because MonoBehaviour scripts in an `Editor` folder can't be attached to GameObjects.
3. In the Hierarchy window, right-click one or more GameObjects and open the **Hierarchy Samples** submenu. Select **Turn into Enemy** to add the `Enemy` component, or **Remove Enemy component** to remove it.

```csharp
using System.Collections.Generic;
using Unity.Hierarchy;
using Unity.Hierarchy.Editor;
using UnityEditor;
using UnityEngine;
using UnityEngine.UIElements;

namespace Unity.HierarchySamples.Editor
{
    class CustomContextMenuAction
    {
        [InitializeOnLoadMethod]
        static void Initialize()
        {
            HierarchyWindow.PopulateContextMenu += OnPopulateContextMenu;
        }

        static void OnPopulateContextMenu(HierarchyWindow window, HierarchyView view, HierarchyViewItem item, DropdownMenu menu)
        {
            if (item == null)
                return;

            if (view.Source.GetNodeTypeHandler<HierarchyGameObjectHandler>() == null)
                return;

            List<GameObject> withEnemy = new List<GameObject>();
            List<GameObject> withoutEnemy = new List<GameObject>();

            foreach (HierarchyNode node in view.ViewModel.EnumerateNodesWithFlags(HierarchyNodeFlags.Selected))
            {
                if (view.ViewModel.GetNodeTypeHandler(node) is not HierarchyGameObjectHandler handler)
                    continue;

                GameObject gameObject = handler.GetGameObject(node);
                if (gameObject.TryGetComponent<Enemy>(out _))
                    withEnemy.Add(gameObject);
                else
                    withoutEnemy.Add(gameObject);
            }

            if (withoutEnemy.Count > 0)
            {
                menu.AppendAction("Hierarchy Samples/Turn into Enemy", _ =>
                {
                    foreach (GameObject gameObject in withoutEnemy)
                        Undo.AddComponent<Enemy>(gameObject);
                });
            }

            if (withEnemy.Count > 0)
            {
                menu.AppendAction("Hierarchy Samples/Remove Enemy component", _ =>
                {
                    foreach (GameObject gameObject in withEnemy)
                        Undo.DestroyObjectImmediate(gameObject.GetComponent<Enemy>());
                });
            }
        }
    }
}
```

The following example shows the `Enemy` component that the CustomContextMenuAction example uses.

```csharp
using UnityEngine;

namespace Unity.HierarchySamples
{
    public class Enemy : MonoBehaviour
    {
        // Marker component used by ChangeRowColor and CustomContextMenuAction samples.
    }
}
```

## GetNodeTypeHandler(Hierarchy, string)

Gets the [HierarchyNodeTypeHandler](/engine/6000.7/script-reference/unity/hierarchy/hierarchynodetypehandler.md) instance for the specified node type name from this hierarchy.

```csharp
public static HierarchyNodeTypeHandler GetNodeTypeHandler(this Hierarchy hierarchy, string nodeTypeName)
```

### Parameters

**** (\[Hierarchy]\(/engine/6000.7/script-reference/unity/hierarchy/hierarchy)): The [Hierarchy](/engine/6000.7/script-reference/unity/hierarchy/hierarchy.md) to get the [HierarchyNodeTypeHandler](/engine/6000.7/script-reference/unity/hierarchy/hierarchynodetypehandler.md) from.**** (\[string]\(https\://learn.microsoft.com/dotnet/api/system.string)): The node type name to get the [HierarchyNodeTypeHandler](/engine/6000.7/script-reference/unity/hierarchy/hierarchynodetypehandler.md) for.

### Returns

| Type                                                                                                    | Description                                                                                                  |
| ------------------------------------------------------------------------------------------------------- | ------------------------------------------------------------------------------------------------------------ |
| [HierarchyNodeTypeHandler](/engine/6000.7/script-reference/unity/hierarchy/hierarchynodetypehandler.md) | The [HierarchyNodeTypeHandler](/engine/6000.7/script-reference/unity/hierarchy/hierarchynodetypehandler.md). |

### Remarks

Use this method to retrieve a specific [HierarchyNodeTypeHandler](/engine/6000.7/script-reference/unity/hierarchy/hierarchynodetypehandler.md) instance from a node type name.