單件(Singleton創建型模式)c#簡單例子
需要生成一個實例時，可采用單件模式
例子中只可生成一個玩家，並對玩家進行測試。單線程例子如下：
namespace singletonpattern
{
public partial class SingletonForm : Form
{
public SingletonForm()
{
InitializeComponent();
}
private void btnDisplay_Click(object sender, EventArgs e)
{
player player1 = player.GetPlayer;
player1.jump = "跳一跳";
player1.move = "走一走";//對player1賦值
listBox1.Items.Add("------play1.jump,player1.move-------");
listBox1.Items.AddRange(new string[] { player1.jump, player1.move });
player player2 = player.GetPlayer;//未對player2賦值，但值與player1相同
listBox1.Items.Add("------play2.jump,player2.move-------");
listBox1.Items.AddRange(new string[] { player2.jump, player2.move });
player1.jump = "跳一跳,跑一跑";
player1.move = "走一走，看--看";//修改的player1，player2也被修改，說明是同一個類
listBox1.Items.Add("------play2.jump,player2.move-------");
listBox1.Items.AddRange(new string[] { player2.jump, player2.move });
listBox1.Items.Add(object.ReferenceEquals(player1, player2));//顯示為true,說明兩個為同一個類
}
}
class player
{
private player()//單例第一步，設構造函數為私有的。
{ }
private static player getplayer;
public static player GetPlayer//第二步獲取單例
{
get
{
if (getplayer == null)//判斷是否實例唯一
{
getplayer = new player();
}
return getplayer;
}
}
public string jump { get; set; }//單例中的屬性
public string move { get; set; }
}
}其中 private static player getplayer;
public static player GetPlayer//第二步獲取單例
{
get
{
if (getplayer == null)//判斷是否實例唯一
{
getplayer = new player();
}
return getplayer;
}
}可簡化為一句
public static readonly player GetPlayer = new player();//簡化單例模式
