Class constructor

[system]

Hi,

This is a newbie question, but I really don’t get how class constructors work.

I created a class, say “MyClass”, and want to create a new object in another class, say “MyGame”, and instantiate it with “MyClass”. I code in C# and used the old “new MyClass(parameters)” constructor.

However, this is not allowed in Unity. I tried removing the “MonoBehaviour” inheritance from both classes, but it did not solve anything.

Besides, after reading the documentation, I tried creating a GameObject and using its AddComponent() method. However, I can’t understand where I should pass the parameters to my constructor, and whether I should change the code inside “MyClass”.

Thanks in advance.

[Bunny83]

Custom component, aka MonoBehaviour derived objects, can’t have parameters in it’s constructor and can’t be created manually with new. Components are part of the strategy-design-pattern and can only be created with AddComponent()

For usual classes (not derived from MonoBehaviour) there’s no problem creating them the usual way with new.

class MyClass
{
    public string name;
    public MyClass(string aName)
    {
        name = aName;
    }
}

MyClass mc = new MyClass("FooBar");

[canklot]

You cant use constructors with mono behaviors but you can get something similar like this by attaching a similar script to your prefab.

public class InventoryItem : MonoBehaviour
{
    public ItemDataClass ItemData;

    void Start()
    {
        GetComponent<Image>().sprite = ItemDataParam.ItemIcon;
    }
}

And when you instantiate the object from another script change its ItemData variable after you instantiate it. That way you instantiate the prefab in the editor and also from a script.

public GameObject CreateRandomItem()
    {
       GameObject RandomItem = Instantiate(InventoryItemPrefab);
       RandomItem.ItemData = GunData;
       return RandomItem;
   }