public struct ComponentLookup<T> where T : unmanaged, IComponentData

ComponentLookup is a native container that provides array-like access to components of a specific type. You can use ComponentLookup to look up data associated with one entity while iterating over a different set of entities. For example, Unity.Transforms stores the Entity object of parent entities in a Parent component and looks up the parent's LocalToWorld matrix using ComponentLookup\<LocalToWorld\> when calculating the world positions of child entities.

To get a ComponentLookup, call ComponentSystemBase.GetComponentLookup.

Pass a ComponentLookup container to a job by defining a public field of the appropriate type in your IJob implementation. You can safely read from ComponentLookup in any job, but by default, you cannot write to components in the container in parallel jobs (including IJobEntity, Entities.Foreach and IJobChunk). If you know that two instances of a parallel job can never write to the same index in the container, you can disable the restriction on parallel writing by adding NativeDisableParallelForRestrictionAttribute to the ComponentLookup field definition in the job struct.

If you would like to access an entity's components outside of a job, consider using the EntityManager methods EntityManager.GetComponentData and EntityManager.SetComponentData instead, to avoid the overhead of creating a ComponentLookup object.