是否有一种方法在所有构造函数运行后立即自动调用特定方法？ [英] Is there a way to automatically call a particular method immediately after all constructors have run?

问题描述

我希望能够在构造派生对象时自动调用特定的方法，但是我不知道该怎么做。以下代码进行了说明。另一个答案是推荐的OnLoad，但是我在Mac上为Unity使用，而我的平台似乎不支持OnLoad。有什么建议吗？

I want to be able to call a particular method automatically upon construction of a derived object, however I can't think how to do it. The following code illustrates. Another answer recommended OnLoad, but I am doing this for Unity on Mac and OnLoad doesn't appear to be supported by my platform. Any suggestions?

public class Parent {

    public Parent ()
    {
        // A. Stuff to do before child constructor code runs
        DoThisAutomaticallyAfterConstruction();
    }

    public void DoThisAutomaticallyAfterConstruction()
    {
        // C. In this example, this will run after A, before B. I want it to run ABC
    }
}

public class Child : Parent {

    public Child () : base()
    {
        // B. Stuff to do here after parent constructor code runs
    }
}

推荐答案

不幸的是，没有内置的方法可以执行您想要的操作（这是一项经常需要的功能）。

Unfortunately there's no built-in way to do what you want (it's a fairly-often-requested feature).

一个解决方法是实现工厂模式，在这种模式下，您无需直接调用构造函数来创建对象，而是实现静态方法来为您创建对象。例如：

One workaround is to implement a factory pattern, where you don't create objects by calling the constructor directly, but instead implement a static method to create them for you. For example:

public class MyClass
{
  public MyClass()
  {
    // Don't call virtual methods here!
  }

  public virtual void Initialize()
  {
    // Do stuff -- but may be overridden by derived classes!
  }
}

然后添加：

public static MyClass Create()
{
  var result = new MyClass();

  // Safe to call a virtual method here
  result.Initialize();

  // Now you can do any other post-constructor stuff

  return result;
}

而不是

var test = new MyClass();

您可以做

var test = MyClass.Create();

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