Question

我有一个班级Character，可存储3个CharacterAttribute班级。我想要的是，如果在Character个类之一内引发事件，CharacterAttribute会在某一点上做某事。

class Character
{
    public CharacterAttribute Physical;

    public Character Create(...) 
    {
        Physical = new CharacterAttribute();
        Physical.SkillPointGained += this.OnSkillPointGained(); 
        // ERROR: cannot convert void to System.EventHandler
    }

    public void OnSkillPointGained()
    {
        // do stuff here after the event has been fired
    }
}

class CharacterAttribute
{
    public event EventHandler SkillPointGained;

    public void GainExperience(...)
    {
        SkillPointGained(this, new EventArgs()); // would raise the event here
    }
}

我得到一个＆＃34;无法隐式地将void转换为System.EventHandler＆＃34;错误。我错过了什么？

Answer 1

需要修改两行代码。

public void OnSkillPointGained()

应为：

void OnSkillPointGained(object sender, EventArgs e)

和

Physical.SkillPointGained += this.OnSkillPointGained();

应阅读：

Physical.SkillPointGained += this.OnSkillPointGained;

（...但是我更喜欢Marc的优雅答案。）

Answer 2

EventHandler的代理签名为void EventHandler(object sender, EventArgs args)。你是：匹配错误的签名，b：你调用方法，而不是将方法作为委托。

但你可以作弊：

Physical.SkillPointGained += delegate { this.OnSkillPointGained(); };

这会创建一个匿名方法，充当立即处理程序，删除发件人/ args，并调用OnSkillPointGained方法。

为单独的类设置事件

2 个答案: