简单工厂设计模式

 1 using System;
 2 using System.Collections.Generic;
 3 using System.ComponentModel;
 4 using System.Data;
 5 using System.Drawing;
 6 using System.Linq;
 7 using System.Text;
 8 using System.Windows.Forms;
 9 
10 namespace _04单例设计模式
11 {
12     public partial class Form2 : Form
13     {
14         //第一步：构造函数私有化
15         private Form2()
16         {
17             InitializeComponent();
18         }
19 
20         //第二部：声明一个静态的字段用来存储全局唯一的窗体对象
21         private static Form2 _single = null;
22         //第三步：通过一个静态函数返回一个全局唯一的对象
23 
24         public static Form2 GetSingle()
25         {
26             if (_single == null)
27             {
28                 _single = new Form2();
29             }
30             return _single;
31         }
32 
33         private void Form2_FormClosing(object sender, FormClosingEventArgs e)
34         {
35             //当你关闭窗体的时候 让窗体2的资源不被释放
36             _single = new Form2();
37         }
38     }
39 }

 1 using System;
 2 using System.Collections.Generic;
 3 using System.ComponentModel;
 4 using System.Data;
 5 using System.Drawing;
 6 using System.Linq;
 7 using System.Text;
 8 using System.Threading.Tasks;
 9 using System.Windows.Forms;
10 
11 namespace WindowsFormsApplication3
12 {
13     public partial class Form1 : Form
14     {
15         public Form1()
16         {
17             InitializeComponent();
18         }
19 
20         private void button1_Click(object sender, EventArgs e)
21         {
22             //没有form2,就先实例化，否则出现原先的form2
23             if (SingleObject.GetSingle().F2 == null)
24             {
25                 SingleObject.GetSingle().F2 = new Form2();
26             }
27             SingleObject.GetSingle().F2.Show();
28 
29         }
30 
31         private void button2_Click(object sender, EventArgs e)
32         {
33             if (SingleObject.GetSingle().F3 == null)
34             {
35                 SingleObject.GetSingle().F3 = new Form3();
36             }
37             SingleObject.GetSingle().F3.Show();
38         }
39     }
40 }