如何在类中保存一个方法以便稍后执行

Question

I need to know how to pass a method into a class constructor so that it can be called later. The idea is to have a Bullet class that has two properties, a damage integer and a Method that can be called when a bullet of that type has hit an object. The code below should explain a bit better:

public class Bullet
{
    public Method OnHit;
    public int Damage;
    public Bullet(int Damage,Method OnHit)
    {
        this.Damage = Damage;
        this.OnHit = OnHit;
    }
}

This is so I can make bullets that preform different tasks upon impact by running something like Bullet.OnHit(HitGameObject).

Answer 1

You can use Action to pass a function to a function then store it in another Action . The function that is stored can be called with Action.Invoke() .

public class Bullet
{
    public int Damage;
    System.Action savedFunc;

    public Bullet(int Damage, System.Action OnHit)
    {
        if (OnHit == null)
        {
            throw new ArgumentNullException("OnHit");
        }

        this.Damage = Damage;
        savedFunc = OnHit;
    }

    //Somewhere in your Bullet script when bullet damage == Damage
    void yourLogicalCode()
    {
        int someBulletDamage = 30;
        if (someBulletDamage == Damage)
        {
            //Call the function
            savedFunc.Invoke();
        }
    }
}

Usage :

void Start()
{
    Bullet bullet = new Bullet(30, myCallBackMethod);
}

void myCallBackMethod()
{

}

Answer 2

What you need is called delegates in c#, First you should define method input/output and then you work with methods of this type just like variables.

public class Bullet
{
public delegate void OnHit(bool something);
public OnHit onHitMethod;
public int Damage;
public Bullet(int Damage, OnHit OnHit)
{
    this.Damage = Damage;
    this.onHitMethod = OnHit;
}
}

in this line public delegate void OnHit(bool something); you just defined the type of delegate and in this line public OnHit onHitMethod; you defined the method just like a variable.