Making Instances of MonoBehaviour Classes

Questions & Answers
1

Hi,
I’ve been struggling on this for quite some time and would love to get some help on this.
Here it is:
I have three scripts:
public class PlayerOneShooting: MonoBehaviour {
public static GameObject pistol;
public static GameObject pistolBullet;

    GunBehaviour GunInHand;
    GunBehaviour Pistol = new GunBehaviour(1f, new BulletBehaviour(4f, 8f, 25, pistolBullet), pistol, "PlayerHand1", "Pistol");
    void Start()
    {
        GunInHand = Instantiate
    }


    public GameObject ConstructGun()
    {
        GameObject tempGIH = (GameObject)Instantiate(Prefab, GameObject.Find(Playerhand).transform.position, GameObject.Find(Playerhand).transform.rotation);
        tempGIH.transform.parent = GameObject.Find(Playerhand).transform;
        return tempGIH;
    }

    void Update()
    {
        if (Input.GetKeyDown(KeyCode.Space))
        {
            GunInHand.Fire();
        }
    }


}

public class GunBehaviour : MonoBehaviour {
    float Reload;
    BulletBehaviour Bullet;
    GameObject Prefab;
    string Playerhand;
    string Name;

    public GunBehaviour(float reload,BulletBehaviour bullet,GameObject prefab,string playerhand,string name)
    {
        Reload = reload;
        Bullet = bullet;
        Prefab = prefab;
        Playerhand = playerhand;
        Name = name;
    }
    public GameObject Construct()
    {
        GameObject tempGIH = (GameObject)Instantiate(Prefab, GameObject.Find(Playerhand).transform.position, GameObject.Find(Playerhand).transform.rotation);
        tempGIH.transform.parent = GameObject.Find(Playerhand).transform;
        return tempGIH;
    }
    public void Fire()
    {
        BulletBehaviour COB = Instantiate(Bullet);
        COB.Construct(Prefab.transform.GetChild(0));
    }
}

public class BulletBehaviour : MonoBehaviour {
    float Lifetime;
    float Speed;
    int Power;
    GameObject Prefab;
    GameObject Obj;

    public BulletBehaviour(float lifetime,float speed, int power, GameObject prefab)
    {
        Lifetime = lifetime;
        Speed = speed;
        Power = power;
        Prefab = prefab;
    }
    void Awake()
    {
        Destroy(Obj, Lifetime);
    }
    void Update()
    {
        Obj.transform.Translate(Vector3.forward * Speed * Time.deltaTime);
    }
    public void Construct(Transform spawn)
    {
        Obj = (GameObject) Instantiate(Prefab, spawn.position, spawn.rotation);
    }
}

There is a fundamental issue here, something I believe about not being able to create new objects of Guns that use monobehaviour. How do I solve.

2

MonoBehaviours are not meant to be constructed by yourself, and thus cannot be constructed using the new keyword. You should use prefabs instead (Documentation).

3

I have a case where I want to use a MonoBehavior class without requiring that it be added to any scene. A general solution in that case is:

GameObject gameObject = new GameObject();
T instance  = gameObject.AddComponent();

where T is the MonoBehavior class you need to create an instance of.