CODE EXAMPLE FOR CSHARP

item switch unity

using UnityEngine;

public class WeaponSwitching : MonoBehaviour
{
    public int selectedWeapon = 0;

    // Start is called before the first frame update
    void Start()
    {
        selectWeapon();
    }

    // Update is called once per frame
    void Update()
    {
        int previousSelectedWeapon = selectedWeapon;

        if(Input.GetAxis("Mouse ScrollWheel") > 0f)
        {
            if(selectedWeapon >= transform.childCount - 1)
                selectedWeapon = 0;
            else
                selectedWeapon++;
        }
        if(Input.GetAxis("Mouse ScrollWheel") < 0f)
        {
            if(selectedWeapon <= 0)
                selectedWeapon = transform.childCount - 1;
            else
                selectedWeapon--;
        }

        if(Input.GetKeyDown(KeyCode.Alpha1))
        {
            selectedWeapon = 0;
        }

        if(Input.GetKeyDown(KeyCode.Alpha2) && transform.childCount >= 2)
        {
            selectedWeapon = 1;
        }
        if(Input.GetKeyDown(KeyCode.Alpha3) && transform.childCount >= 3)
        {
            selectedWeapon = 2;
        }

        if(previousSelectedWeapon != selectedWeapon)
        {
            selectWeapon();
        }
    }

    void selectWeapon()
    {
        int i =  0;
        foreach(Transform weapon in transform)
        {
            if(i == selectedWeapon)
                weapon.gameObject.SetActive(true);
            else
                weapon.gameObject.SetActive(false);
            i++;
        }
    }
}