NullReferenceException: Object reference not set to an instance of an object & You are trying to create a MonoBehaviour using the 'new' keyword.

I get this null reference with i click P (Adding item id 0 (Apple) to my inventory pointing to this line " if(itm.itemID == id)"

As well as in the "Item" Script i get an error "You are trying to create a MonoBehaviour using the 'new' keyword. This is not allowed. MonoBehaviours can only be added using AddComponent(). Alternatively, your script can inherit from ScriptableObject or no base class at all UnityEngine.MonoBehaviour:.ctor()"

SCRIPT "GameDB" using System.Collections; using System.Collections.Generic; using UnityEngine;

public class GameDB : MonoBehaviour {

 public List<Item> items = new List<Item>();

 private void Start()
 {
     ItemDatabaseSetup();
 }

 private void ItemDatabaseSetup()
 {
     items.Add(new Item("Apple", "Gives Hunger", "Apple_Item", 0));
     items.Add(new Item("Water", "Gives Thirst", "Water_Item", 1));
 }

 public Item GetItemByID(int id)
 {
     foreach(Item itm in items)
     {
         if(itm.itemID == id) ➜ ➜ ➜ ➜ ➜ ➜ ➜ ➜ ➜ ➜  ER1
         {
             return itm;
         }
     }

     Debug.LogError("Cant find item by ID!");
     return null;
 }

}

PART OF INVENOTRY public void AddItem(int id) {

     if (gameDB == null)
     {
         gameDB = GameObject.FindGameObjectWithTag("GameDB").GetComponent<GameDB>();
     }

     Item itemAdd = gameDB.GetItemByID(id);

     for(int i = 0; i < slots.Count; i++)
     {
         if (slots[i].transform.childCount <= 0)
         {
             GameObject itemInstance = Instantiate(itemPrefab);
             itemInstance.transform.SetParent(slots[i].transform);
             itemInstance.transform.localPosition = Vector2.zero;
             itemPrefab.GetComponent<Image>().sprite = itemAdd.itemSprite;
             break;
         }
     }
 }

}

"Item Script"

using System; using System.Collections; using UnityEngine; using UnityEngine.EventSystems; using UnityEngine.UI;

[System.Serializable] public class Item : MonoBehaviour, IDragHandler, IBeginDragHandler, IEndDragHandler {

 public string itemName;
 public string itemDescription;
 public Sprite itemSprite;
 public string spriteName;
 public int itemID;

 public Item(string name, string description, string spriteName, int id) ➜ ➜ ➜ ➜ ➜  ➜ ➜ ➜ER2
 {
     itemName = name;
     itemDescription = description;
     itemSprite = Resources.Load<Sprite>("ItemIcons/" + spriteName);
     itemID = id;
 }

 public Item()
 {

 }

 private Transform startParent;

 private CanvasGroup canvasGroup;

 private void Start()
 {
     startParent = transform.parent;

     canvasGroup = GetComponent<CanvasGroup>();
 }

 public void OnBeginDrag(IPointerEnterData eventData)
 {
     transform.position = eventData.position;

     transform.SetParent(transform.parent.parent);

     canvasGroup.blocksRaycasts = false;

 }

 public void OnDrag(PointerEventData eventData)
 {
     transform.position = eventData.position;
 }

 public void OnEndDrag(PointerEventData eventData)
 {
     transform.SetParent(startParent); // Reset Parent
     transform.localPosition = Vector2.zero; //Reset Position
     canvasGroup.blocksRaycasts = true;
 }

 void IBeginDragHandler.OnBeginDrag(PointerEventData eventData)
 {
     throw new NotImplementedException();
 }

}