Method HasComponent
HasComponent<T>(Entity)
Checks whether an entity has a specific type of component.
Declaration
protected bool HasComponent<T>(Entity entity)
where T : struct, IComponentDataParameters
| Type | Name | Description |
|---|---|---|
| Entity | entity | The Entity object. |
Returns
| Type | Description |
|---|---|
| Boolean | True, if the specified entity has the component. |
Type Parameters
| Name | Description |
|---|---|
| T | The data type of the component. |
Remarks
Always returns false for an entity that has been destroyed.
Use this method to check if another entity has a given type of component using its Entity object. For example, if you have a component that contains an Entity field, you can check whether the referenced entity has a specific type of component using this method. (Entities in the set always have required components, so you don’t need to check for them.)
When iterating over a set of entities via Entities.ForEach, avoid using this method with the current entity in the set. It is generally faster to change your entity query methods to avoid optional components; this may require a different Entities.ForEach construction to handle each combination of optional and non-optional components.
When you call this method on the main thread, it invokes HasComponent<T>(Entity).
(An Entities.ForEach function invoked with Run() executes on the main thread.) When you call this method
inside a job scheduled using Entities.ForEach, this method gets replaced with component access methods
through ComponentDataFromEntity<T>.
In both cases, this lookup method results in a slower, indirect memory access. When possible, organize your data to minimize the need for indirect lookups.