godot-------/Script/Item/BagItem.cs

using Godot;
using System;
using System.Collections.Generic;

public partial class BagItem
{
    public ItemResource itemResource;
    public int amount;

    public string ItemName
    {
        get
        {
            return itemResource?.ItemName ?? "Unknown"; // 防止空引用
        }
    }

    public string Description
    {
        get
        {
            return itemResource?.Description ?? "No description"; // 防止空引用
        }
    }

    public void AddAmount(int value)
    {
        if (value < 0)
        {
            GD.PrintErr("Cannot add negative amount to BagItem.");
            return;
        }
        amount += value;
    }

    public void RemoveAmount(int value)
    {
        if (value < 0 || value > amount)
        {
            GD.PrintErr("Invalid amount to remove from BagItem.");
            return;
        }
        amount -= value;
    }
}