Question Calling SetComponent or GetComponent from a function in Entities.ForEach

I wrote the following function and want to be able to call it from Entities.Foreach:

Code (CSharp):

1. private void AssignTarget(Entity e, Entity target, EntityCommandBuffer ecb){
2.         TargetComponent targetComp = new TargetComponent{
3.                         target = target,
4.         };
5.         ecb.AddComponent<TargetComponent>(e, targetComp);
6.  
7.         NumAttackingComponent targetNum = GetComponent<NumAttackingComponent>(target);
8.         targetNum.numAttacking += 1;
9.         SetComponent<NumAttackingComponent>(target, targetNum);
10.     }

The issue is I get an error about non-valued 'this'. I'd like to make functions for bits of code I reuse often that mirror Entities.Foreach code, and then only use them in Entities.Foreach. Is this possible or do I need to pass in an EntityManager or something of the sort?

 

You generally can't use any instance members in Entities.ForEach, so you would have to use static methods and pass in something that would get you access to GetComponent / SetComponent, so either the EntityManager or ComponentLookup (on 1.0 exp/preview, or ComponentDataFromEntity on previous). Personally, I would say the better design would be using ComponentLookup, which would allow you to reuse these across IJobEntity and Entities.ForEach with no consequences.

 

I should have mentioned I am looking to do this exclusively with static functions. Thanks for the info! I figured that would be the case. GetComponent calls ComponentDataFromEntity, so the runtime should be similar between the two implementations, correct?

 

Yeah, they should be similar with how the codegen for Entities.ForEach works out (I believe it just injects a ComponentLookup for the SystemBase.Get/SetComponent calls).