Inconsistent accessibility error for event handler

Hi,
I am creating my own Input Handler script based on Tactics RPG input controller, but i get an error:

Here is my code:

using System.Collections;

using System.Collections.Generic;

using UnityEngine;

using System;

using UnityEngine.EventSystems;



public class InputController : MonoBehaviour {



//This line get the error

public static event EventHandler<InfoEventArgs<ButtonList>> tombol;





public void OnArrowDown(){

tombol(this, new InfoEventArgs <ButtonList> (ButtonList.ArrowDown));

Debug.Log ("Tombol Arah Bawah Pressed");

}

public void OnArrowUp(){

tombol(this, new InfoEventArgs <ButtonList> (ButtonList.ArrowUp));

Debug.Log ("Tombol Arah Atas Pressed");

}

public void OnArrowRight(){

tombol(this, new InfoEventArgs <ButtonList> (ButtonList.ArrowRight));

Debug.Log ("Tombol Arah Kanan Pressed");

}

public void OnArrowLeft(){

tombol(this, new InfoEventArgs <ButtonList> (ButtonList.ArrowLeft));

Debug.Log ("Tombol Arah Kiri Pressed");

}

public void OnAction1(){

tombol(this, new InfoEventArgs <ButtonList> (ButtonList.Action1));

Debug.Log ("Tombol Next Pressed");

}

public void OnAction2(){

tombol(this, new InfoEventArgs <ButtonList> (ButtonList.Action2));

Debug.Log ("Tombol Next Pressed");

}

}



I have googled here and there, and all the answer i got is that i have to make my class public. yet my InputController class has already public.

Instead if I make either the class or the EventHandler not public, the error is gone, but of course, the code also not work.

I use the similar EventHandler for different project (includeng Tatics RPG), yet they work perfectly fine. I wonder if i miss something.

Btw, ButtonList in code above is an Enum listing name of some button.

For InfoEventArgs, its the raw copy from Tactics Rpg:

public class InfoEventArgs<T> : EventArgs {



public T info;



public InfoEventArgs(){

info = default(T);

}



public InfoEventArgs(T info){

this.info = info;

}

}