C# - Get and Set 存取器

語法

……… // 宣告變數(通常是 public)
{ get { …. } // 希望變數讀取時執行的程式碼
set { …. } // 希望數值存入時執行的程式碼
}

class User
   {
       private string Username;
       private string Password;
     private int hp;
       public int HP
       {
           get { return hp; }//在讀取 HP 時會自動呼叫
           set { if (value < 0) {//在存入數值時自動呼叫
                   hp = 0;
               } else {
                   hp = value;
               } }
       }

       public void hurt(int decreaseHP)
       {
           if (hp >= decreaseHP)
           {
               hp -= decreaseHP;
           }
           else
           {
               hp = 0;
           }
       }
       public int getHP()
       {
           return hp;
       }

       public User(string Username, string Password)
       {
           this.Username = Username;
           this.Password = Password;
           this.hp = 30;
       }





       }

private void button1_Click(object sender, EventArgs e)
        {
            User user = new User("Tum","1234");
            MessageBox.Show(""+user.HP);        }

如果只留下 get 存取器，該變數就會變成「唯讀」

Get & Set 存取器可以用來即時運算一些平常大家認為是變數的數值，像是 Money

class User
    {
        
        private int count1, count5, count10;
        public int Money
        {
            get { return count1 + count5 * 5 + count10 * 10; }
        }
    
        
        public User(string Username, string Password)
        {
            this.Username = Username;
            this.Password = Password;
            this.hp = 30;
            this.count1 = 1;
            this.count5 = 1;
            this.count10 = 1;

        }
       
        
        }

private void button1_Click(object sender, EventArgs e)
      {
          User user = new User("Tum","1234");
      
          MessageBox.Show(""+user.Money);        }