C# 建立 EventHandler & 移除 EventHandler

 
C# 建立 EventHandler & 移除 EventHandler
 

   Form1.cs
 
   public Form1()
   {
      InitializeComponent();
 
      button3.Text = "Remove Button 5 EventHandler";
      button4.Text = "Add Button 5 EventHandler";
   }
 
   private void button3_Click(object sender, EventArgs e)
   {
      button5.Click -= new System.EventHandler(this.button5_Click);
      label1.Text = "";
   }
 
   private void button4_Click(object sender, EventArgs e)
   {
      button5.Click += new System.EventHandler(this.button5_Click);
      label1.Text = "";
   }
 
   private void button5_Click(object sender, EventArgs e)
   {
      label1.Text = "Event Active";
   }