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Game.Common.Event

Assembly: Assembly-CSharp
Namespace: Game.Common

Type: struct

Base: System.ValueType, implements Unity.Entities.IComponentData, Unity.Entities.IQueryTypeParameter

Summary: A zero-data "tag" or marker component used to represent a transient event in ECS. The struct is explicitly laid out with Size = 1 byte so it can be used as a minimal footprint component for signaling. Because it implements IQueryTypeParameter it can be used directly in query construction (e.g., WithAll()). {{ This component is intended as a lightweight, transient marker — add it to entities to signal that an event has occurred, then remove it after processing (typically within the same frame). For multithreaded systems, use an EntityCommandBuffer to add/remove this tag. }}

Fields

  • None. {{ This struct declares no fields; the StructLayout attribute sets its size to 1 byte even though it contains no managed fields. That is an intentional optimization for tag components. }}

Properties

  • None. {{ There are no properties on this type. It is an empty tag component. }}

Constructors

  • Implicit default constructor (value-type default) {{ As a struct, Event has the implicit default constructor that initializes it to its default value. You can construct it with "new Event()" when adding component data, but no state is stored. }}

Methods

  • None. {{ No instance or static methods are defined. Interaction is via ECS APIs (add/remove/query) rather than methods on the type. }}

Usage Example

using Unity.Entities;

// Add the tag to an entity (EntityManager)
entityManager.AddComponentData(entity, new Game.Common.Event());
// or
entityManager.AddComponent(entity, typeof(Game.Common.Event));

// Query entities that have the Event tag in a SystemBase
public partial class EventProcessingSystem : SystemBase
{
    protected override void OnUpdate()
    {
        // Example: process all entities with the Event tag, then remove the tag
        var ecb = new EntityCommandBuffer(Unity.Collections.Allocator.Temp);
        Entities
            .WithAll<Game.Common.Event>()
            .ForEach((Entity entity) =>
            {
                // Handle the event for 'entity' here

                // Remove the tag so the event is one-frame only
                ecb.RemoveComponent<Game.Common.Event>(entity);
            }).Run();
        ecb.Playback(EntityManager);
        ecb.Dispose();
    }
}

{{ Best practices: treat this as a one-frame event marker. For thread-safe adds/removes, use an EntityCommandBuffer or the parallel ECB variant. Avoid storing state in tag components; use separate components for persistent data. }}