Question

所以我创建了一个将存储许多方法的类。然后打电话给他们（忽略Unity 3D，因为这是一个c＃问题）

using UnityEngine;
using System.Collections;
using System;

namespace Beast.Extensions
{

public class MethodList : MonoBehaviour
{

    public MethodList (params System.Action[] _methods)
    {
        this.methods = new Action[_methods.Length];
    }

    public Action[] methods { get; set; }

    /// <summary>
    /// Calls a specific method in the list.
    /// </summary>
    /// <param name="method"></param>
    public void Call (int method)
    {
        this.methods[method]();
    }

    /// <summary>
    /// Calls all of the methods in this method group in order.
    /// </summary>
    public void CallAll()
    {
        int l = this.methods.Length;
        for (int x = 0; x < l; x++)
        {
            this.methods[x]();
        }
    }


    }
}

以下是我如何使用它并调用它。

 MethodList deathMethods = new MethodList(() =>  print("Killing"), () => print("Dead"), () => Debug.Log("Dead a while ago."), () => print("Officially dead"));


deathMethods.Call(0); //Expected output: Killing
deathMethods.CallAll(); //Expected output: "Killing Dead a while ago Officially dead"

所有这些错误：

对象引用未设置为对象的实例

Answer 1

ctor只创建数组，但不分配_methods的内容。

public MethodList(params Action [] _methods){
    this.methods = _methods;
}

Answer 2

这对我有用：

public MethodList(params Action[] methods)
{
    Methods = methods;
}
public void Call(int num) =>  Methods[num]();
public void CallAll()
{
    foreach (var method in Methods) method();
}

您必须将this.Methods设置为method。您只创建了一个大小为_method的数组，但您没有对this.Methods执行任何操作，因此它仍然是null，您也没有对_method中存储的值执行任何操作

您还可以添加索引器，如下所示：

public Action this[int index]
{
    get { return Methods[index]; }
    set { Methods[index] = value; }
}

并像这样使用它：

methodList[2] = () => Console.WriteLine("Alive again");
methodList[2]();

Action数组的问题

2 个答案: