ISystemStateComponentData Sample

Component.cs

using Unity.Entities;
using System;

public struct Life : IComponentData{}

[Serializable]
public struct LifeState : ISystemStateComponentData
{
    public Place lastPlace;
}

public enum Place
{
    Office,
    Home
}

LifeSpawner.cs

using UnityEngine;
using Unity.Entities;

public class LifeSpawner : MonoBehaviour
{
    void Start()
    {
        Debug.Log("Entity生成");
        World.Active.EntityManager.CreateEntity(
            ComponentType.ReadWrite<Life>(), 
            ComponentType.ReadWrite<LifeState>());
    }
}

System.cs

using UnityEngine;
using Unity.Entities;
using Unity.Jobs;

/// <summary>
/// Lifeの居る場所を切り替えるだけ
/// 
/// Zキー:家に移動
/// Xキー：オフィスに移動
/// </summary>
public class LifeSystem : ComponentSystem
{
    protected override void OnUpdate()
    {
        if (Input.GetKeyDown(KeyCode.Z))
        {
            Entities.ForEach((ref LifeState state) => state.lastPlace = Place.Home);
            Debug.Log($"今は{ Place.Home }に居ます");
        }
        if (Input.GetKeyDown(KeyCode.X))
        {
            Entities.ForEach((ref LifeState state) => state.lastPlace = Place.Office);
            Debug.Log($"今は{ Place.Office }に居ます");
        }
    }
}

/// <summary>
/// Lifeを全て殺す
/// 
/// Aキー：殺す
/// </summary>
public class MurderSystem : ComponentSystem
{
    protected override void OnUpdate()
    {
        if (Input.GetKeyDown(KeyCode.A))
        {
            Debug.Log("死ね！ Entity!!!");
            Entities.WithAll<Life>().ForEach((Entity entity) => PostUpdateCommands.DestroyEntity(entity));
        }
    }
}

/// <summary>
/// 遺言を表示
/// Lifeが最後に居た場所を表示する
/// </summary>
public class EndLifeSystem : ComponentSystem
{
    protected override void OnUpdate()
    {
        Entities.WithNone<Life>().ForEach((Entity entity, ref LifeState state) => 
        {
            Debug.Log($"死ぬ前に居た場所は{state.lastPlace}です");
            PostUpdateCommands.RemoveComponent<LifeState>(entity);
        });
    }
}