在類別裡判斷物件的屬性以過濾事件是否觸發

2013-10-18

傳統上，物件裡以+=來使用事件，不使用時用-=，
但有些情況必須頻繁的 += 與 -= ，若判斷很多就會加深複雜度，
如果物件裡的某個屬性可以做為判斷，就可以只用+=，再由類別取出物件的屬性來判斷是否執行事件處理的方法。


using System;
using System.Windows.Forms;

namespace WindowsFormsApplication1
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        public delegate void buttonClickEventHandle();
        public event buttonClickEventHandle buttonClick;
        MyClass fa,fb;

        private void Form1_Load(object sender, EventArgs eee)
        {
            fa = new MyClass(this, "fa");
            fb = new MyClass(this, "fb");
        }

        private void checkBox1_CheckedChanged(object sender, EventArgs e)
        {
            fa.Active = checkBox1.Checked;
        }

        private void checkBox2_CheckedChanged(object sender, EventArgs e)
        {
            fb.Active = checkBox2.Checked;
        }

        private void button1_Click(object sender, EventArgs e)
        {
            foreach (Delegate d in  buttonClick.GetInvocationList())
            {
                MyClass m = (MyClass)d.Target;
                if (m.Active)
                    d.Method.Invoke(m, null);
            }
        }

        internal class MyClass
        {
            internal Form1 form1;
            internal string Name { set; get; }
            internal bool Active { set; get; }

            internal MyClass(Form1 form1, string name)
            {
                this.form1 = form1;
                this.Name = name;
                form1.buttonClick += form1_buttonClick;
            }

            void form1_buttonClick()
            {
                MessageBox.Show(this.Name);
            }
        }
    }
}

事件.rar

回首頁