void Refresh()
{
var itemList = inventory.GetItemList();
for (int i = 0; i < gridList.Count; i++)
{
ItemSlot slot = gridList.GetElement <ItemSlot>(i);
if (i >= itemList.Count)
{
slot.Item = null;
}
else
{
slot.Item = (itemList[i] == Item.NullItem ? null : itemList[i]);
}
}
}
