# BindViewItem

> Raised when a HierarchyViewItem is bound to a HierarchyView. Use this event to customize the view item.

## Definition

* **Type:** Event
* **Namespace:** [Unity.Hierarchy.Editor](/engine/6000.7/script-reference/unity/hierarchy/editor.md)
* **Assembly:** UnityEditor

```csharp
public static event HierarchyWindow.BindViewItemEventHandler BindViewItem
```

### Remarks

The following example changes the icon a GameObject uses in the Hierarchy window if it has a specified tag. It uses `BindViewItem` to register a handler that customizes each item as the window binds it, and applies a custom USS icon class to GameObjects with the `Favorite` tag.

The example requires a USS file called `ChangeNodeIcon.uss` and a tag called `Favorite`.

To use this example:

1. Save the script in a folder called `Assets/Editor/ChangeNodeIcon`. 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. Copy the styles from the USS example on this page. Save them in a USS file called `ChangeNodeIcon.uss` in the same `Assets/Editor/ChangeNodeIcon` folder.
3. Create a tag called `Favorite`: select a GameObject, open the **Tag** dropdown in the **Inspector** window, and select **Add Tag**.
4. Assign the `Favorite` tag to a GameObject to change the icon it displays.

```csharp
using Unity.Hierarchy;
using Unity.Hierarchy.Editor;
using UnityEditor;
using UnityEngine;
using UnityEngine.UIElements;

namespace Unity.HierarchySamples.Editor
{
    class ChangeNodeIcon
    {
        const string k_FavoriteUssClass = "gameobject--favorite";

        [InitializeOnLoadMethod]
        static void Initialize()
        {
            HierarchyWindow.BindView += OnBindView;
            HierarchyWindow.BindViewItem += OnBindViewItem;
        }

        static void OnBindView(HierarchyWindow window, HierarchyView view)
        {
            view.styleSheets.Add(AssetDatabase.LoadAssetAtPath<StyleSheet>("Assets/Editor/ChangeNodeIcon/ChangeNodeIcon.uss"));
        }

        static void OnBindViewItem(HierarchyWindow window, HierarchyView view, HierarchyViewItem item)
        {
            if (item.Handler is not HierarchyGameObjectHandler handler)
                return;

            GameObject gameObject = handler.GetGameObject(item.Node);
            if (gameObject == null)
                return;

            // CompareTag throws an error if the 'Favorite' tag isn't defined in the project.
            // To define the 'Favorite' tag, select a GameObject, open the Tag dropdown in the Inspector window, select Add Tag, and create a new tag called 'Favorite'.
            if (System.Array.IndexOf(UnityEditorInternal.InternalEditorUtility.tags, "Favorite") < 0)
                return;

            bool isFavorite = gameObject.CompareTag("Favorite");
            item.Icon.EnableInClassList(k_FavoriteUssClass, isFavorite);
            // Inline styling needs to be cleared to show custom USS icon.
            if (isFavorite)
                item.Icon.style.backgroundImage = StyleKeyword.Null;
        }
    }
}
```

The following example shows how to style `ChangeNodeIcon.uss`.

```csharp
.hierarchy-item__icon.gameobject--favorite {
    background-image: resource("Icons/Favorite_colored.png");
}

.unity-collection-view__item--selected:hover:enabled .hierarchy-itemicon.gameobject--favorite,
.unity-collection-view:focus .unity-collection-viewitem--selected .hierarchy-itemicon.gameobject--favorite {
    background-image: resource("Icons/Favorite_colored.png");
}
```