如何把 ref 保存起来？

Question

class Change // A:正确的写法
{
    public void Update(ref int i, int newValue)
    {
        i = newValue;
    }
}
class Change // B:我想达到的目标
{
    public void SetValueRef(ref int i);
    public void Update(int newValue);
}

如上面的代码，我们知道A可以实现修改一个变量的值，但是 ref i 的传入和值的修改必定同时发生。我想要，先把 ref i 传入，未来需要的时候再修改 i 的值，这该如何实现？或者有什么变通的方法？

Answer 1

如果你想调用Update方法（手动调用）才更改i，那么可以考虑设置一个布尔值：

class Change // B:我想达到的目标
{
    public void Update(int newValue,ref int i,bool flag)
    {
       if(flag)
       {
           i = newValue;
       }
    }
}

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Answer 2

这样不解决问题哪……更改 i 值的时候，还是一定得现场把 ref 引用传进去。

Answer 3

因为ref只能在函数中用，不能用于事件啥的，要不用类封装一下，借助类的特性改变。譬如：

public class A
    {
        public int I { get; set; }
 
        public A(int i)
        {
            I = i;
        }
 
        /// <summary>
        /// 更新数据的方法
        /// </summary>
        public void Update(int newInt)
        {
            I = newInt;
        }
    }
    public class MainTest
    {
        static void Main(string[] args)
        {
            A a = new A(0);
            Console.WriteLine("源数据："+a.I);
            a.Update(2);
            Console.WriteLine("新数据："+a.I);
        }
    }

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Answer 4

嗯，我目前就是这么做的。多谢～