c# - 有没有办法批量注册事件？

Question

我有许多母类，每个类都有不同数量的相同类型的子对象。并且母类需要向所有这些子对象注册一个事件。

想知道有没有什么好办法自动注册？

比如：遍历母类中的所有属性，找到子类的属性，然后注册事件。

Answer 1

您可以使用反射来订阅事件。

定义子类：

    class Child {
        public Child() { }            

        // Define event
        public event EventHandler DidSomethingNaughty;

        // Proeprty used to trigger event
        public bool IsNaughty {
            get { return this.isNaughty; }
            set {
                this.isNaughty = value;
                if (this.IsNaughty) {
                    if (this.DidSomethingNaughty != null) {
                        this.DidSomethingNaughty(this, new EventArgs());
                    }
                }
            }
        }

        // Private data member for property
        private bool isNaughty = false;
    }

定义母类：

    class Mother {

        public Mother() {
            this.subscribeToChildEvent();
        }

        // Properties
        public Child Child1 {
            get { return this.child1; }
            set { this.child1 = value; }
        }

        public Child Child2 {
            get { return this.child1; }
            set { this.child2 = value; }
        }

        public Child Child3 {
            get { return this.child3; }
            set { this.child3 = value; }
        }

        public Child Child4 {
            get { return this.child4; }
            set { this.child4 = value; }
        }

        // Private data members for the properties
        private Child child1 = new Child();
        private Child child2 = new Child();
        private Child child3 = new Child();
        private Child child4 = new Child();

        // This uses reflection to get the properties find those of type child
        // and subscribe to the DidSomethingNaughty event for each
        private void subscribeToChildEvent() {
            System.Reflection.PropertyInfo[] properties = 
                typeof(Mother).GetProperties();
            foreach (System.Reflection.PropertyInfo pi in properties) {
                if (pi.ToString().StartsWith("Child")) {
                    Child child = pi.GetValue(this, null) as Child;
                    child.DidSomethingNaughty +=
                        new EventHandler(child_DidSomethingNaughty);
                }
            }
        }

        private void  child_DidSomethingNaughty(object sender, EventArgs e){
            Child child = (Child)sender;
            if (child.IsNaughty) {
                this.discipline(child);
            }
        }

        private void discipline(Child child) {                
            MessageBox.Show("Someone was naughty");
            // reset the flag so the next time the childe is
            //naughty the event will raise
            child.IsNaughty = false;
        }
    }

然后初始化一个 Mother 对象，它将为事件下标：

    Mother m = new Mother();

然后将 Child1 的 IsNaughty 属性设置为 true：

    m.Child1.IsNaughty = true;

你应该得到一个消息框：

资源：

https://stackoverflow.com/a/737156/1967692

https://stackoverflow.com/a/3179869/1967692