Add scroll wheel.

I have it so keys can be set by any keycode but i cant use scroll wheel with my current code and i cant think of a way set it up so it can read mousewheel up/down as input.

keycontroller

 using System.Collections;
 using System.Collections.Generic;
 using UnityEngine;
 using UnityEngine.Serialization;
 
 
 public class KeyController : MonoBehaviour {
 
     [HideInInspector]
     public bool save;
     [HideInInspector]
     public KeybindV2[] KeyCS;
 
     // Use this for initialization
     void Awake () {
         
     }
 
     // Update is called once per frame
     void Update()
     {
         KeyCS = this.gameObject.GetComponents<KeybindV2>();
     }
 
     public void SaveKeys()
     {
         for (int i = 0; i < KeyCS.Length; i++)
         {
             PlayerPrefs.SetString(KeyCS[i].keyname, KeyCS[i].AllKeys.key.ToString());
         }
     }
 }

key

 using System.Collections.Generic;
 using UnityEngine;
 using UnityEngine.UI;
 using UnityEngine.Serialization;
 using UnityEngine.EventSystems;
 
 public class KeybindV2 : MonoBehaviour {
 
     public string keyname;
     public MyKeys AllKeys;
     public Text Disc;
     [System.Serializable]
     public class MyKeys
     {
         //public GameObject KeyOBJ;
         public string keyname;
         public KeyCode key;
         public bool changekey;
         public Button KeyButton;
         public Text KeyTxt;
     }
 
 
 
     // Use this for initialization
     void Start()
     {
         AllKeys.keyname = Disc.gameObject.name;
         Disc.text = AllKeys.keyname;
         AllKeys.key = (KeyCode)System.Enum.Parse(typeof(KeyCode), PlayerPrefs.GetString(AllKeys.keyname, AllKeys.key.ToString()));
         AllKeys.KeyButton = Disc.gameObject.transform.GetChild(0).GetComponent<Button>();
         AllKeys.KeyTxt = AllKeys.KeyButton.gameObject.transform.GetChild(0).GetComponent<Text>();
     }
 
     // Update is called once per frame
     void Update()
     {
         AllKeys.KeyTxt.text = AllKeys.key.ToString();
         AllKeys.KeyButton.onClick.AddListener(delegate () { this.ChangeKey(); });       
         if (AllKeys.changekey)
         {
             AllKeys.KeyTxt.text = "Unassigned";
             foreach (KeyCode kcode in System.Enum.GetValues(typeof(KeyCode)))
             {
                 if (Input.GetKeyDown(kcode))
                 { 
                     AllKeys.key = (KeyCode)System.Enum.Parse(typeof(KeyCode), kcode.ToString());
                     AllKeys.changekey = false;
                 }
             }
         }
 
         keyname = AllKeys.keyname;
     }
 
     public void ChangeKey()
     {
         AllKeys.changekey = true;
     }
 
     public void SaveKey()
     {
         PlayerPrefs.SetString(AllKeys.keyname, AllKeys.key.ToString());
     }
 }