sharing_hashmaps.cs

using Unity.Entities;
using Unity.Collections;
using UnityEngine;
using Unity.Jobs;
using Unity.Burst;


// ICOMPONENTDATA
public struct MyICD : IComponentData { 
    public int id; 
}


// MONO
class LookupMapTest : MonoBehaviour
{
    NativeHashMap<int,int> myHashMap;

    void Start()
    {
        EntityManager em = World.DefaultGameObjectInjectionWorld.EntityManager;
        Entity e = em.CreateEntity();

        myHashMap = new NativeHashMap<int, int>(256, Allocator.Persistent);
        myHashMap.TryAdd(123,456);
    }

    void OnDestroy(){ myHashMap.Dispose(); }
}


// COMPONENTSYSTEM
public class MySystem : ComponentSystem
{
    protected override void OnUpdate()
    {
        Entities.ForEach((ref MyICD myICD) => { 
            // Need readonly access to hashmap
        });
    }
}


// JOB SYSTEM
public class MyJobSystem : JobComponentSystem
  {
      [BurstCompile]
      struct MyJob : IJobForEachWithEntity<MyICD>
      {
          public int myJobParam;

          public void Execute(Entity entity, int index, [ReadOnly] ref MyICD myICD)
          {
            // Need readonly access to hashmap
          }
      }
  
  
      protected override JobHandle OnUpdate(JobHandle inputDependencies)
      {
          var job = new MyJob()
          {
              myJobParam = 666
          };
          return job.Schedule(this, inputDependencies);
      }
~ }