# applyToCollection

> Makes attribute affect collections instead of their items.

## Definition

* **Type:** Property
* **Namespace:** [UnityEngine](/engine/6000.5/script-reference/unityengine.md)
* **Assembly:** UnityEngine.CoreModule

```csharp
public bool applyToCollection { get; }
```

### Remarks

When you apply a `PropertyAttribute` to a collection, by default Unity applies it to each element of the collection. When `applyToCollection` is `true`, the attribute is applied to the collection itself instead.

You can use this in scenarios where the attribute functionality needs to apply to the collection as a whole rather than per element. Some typical scenarios include:

* A reorderable list header or collection-level label. For example, when creating a drawer that adds a summary line stating the total number of items in the list, or a custom add or remove toolbar.
* An attribute that makes a list non-reorderable, or locks its size.
* Validation across the collection. For example, an attribute that checks that a list contains unique entries or that it has at least three items.

### Examples

```csharp
using UnityEditor;
using UnityEditor.UIElements;
using UnityEngine;
using UnityEngine.UIElements;

public class Collection : MonoBehaviour
{
    public int before;
    [GreenCollectionDrawer] public int[] collection;
    public int after;
}

public class GreenCollectionDrawerAttribute : PropertyAttribute
{
    public GreenCollectionDrawerAttribute() : base(true) { }
}

[CustomPropertyDrawer(typeof(GreenCollectionDrawerAttribute))]
public class GreenCollectionDrawer : PropertyDrawer
{
    public override VisualElement CreatePropertyGUI(SerializedProperty property)
    {
        return new PropertyField(property)
        {
            style =
            {
                backgroundColor = Color.green
            }
        };
    }
}
```