深入.NET平台和C#编程.第五章：上机练习4

---------------------------------------------ChengFa类---------------------------------------------

 1 using System;
 2 using System.Collections.Generic;
 3 using System.Linq;
 4 using System.Text;
 5 using System.Threading.Tasks;
 6 
 7 namespace JiSji
 8 {
 9     public class ChengFa : Operation
10     {
11         /// <summary>
12         /// 乘法类
13         /// </summary>
14         /// <returns></returns>
15         public override double GetResult()
16         {
17             double result = NumberA * NumberB;
18             return result;
19         }
20     }
21 
22 
23 }

View Code

---------------------------------------------ChuFa类-----------------------------------------------

 1 using System;
 2 using System.Collections.Generic;
 3 using System.Linq;
 4 using System.Text;
 5 using System.Threading.Tasks;
 6 
 7 namespace JiSji
 8 {
 9     /// <summary>
10     /// 除法类
11     /// </summary>
12     public class ChuFa : Operation
13     {
14         public override double GetResult()
15         {
16             if (NumberB == 0)
17             {
18                 throw new Exception("除数不能为0！");
19             }
20             double result = NumberA / NumberB;
21             return result;
22         }
23     }
24 
25 
26 }

View Code

---------------------------------------------formJiSji窗口-------------------------------------------

 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 JiSji
12 {
13     public partial class formJiSji : Form
14     {
15         public formJiSji()
16         {
17             InitializeComponent();
18         }
19 
20         /// <summary>
21         /// 计算
22         /// </summary>
23         /// <param name="sender"></param>
24         /// <param name="e"></param>
25         private void button1_Click(object sender, EventArgs e)
26         {
27             if (string.IsNullOrEmpty(this.txtshu1.Text.Trim()) || string.IsNullOrEmpty(this.txtshu2.Text.Trim()))
28             {
29                 MessageBox.Show("操作数不能为空！");
30                 this.txtshu1.Focus();
31             }
32             else
33             {
34                 try
35                 {
36                     Operation opr = new Operation();
37                     switch (this.cmbfuh.SelectedItem.ToString().Trim())
38                     {
39                         case "+":
40                             {
41                                 opr = new JiaFa();
42                             }
43                             break;
44                         case "-":
45                             {
46                                 opr = new JianFa(); 
47                             }
48                             break;
49                         case "*":
50                             {
51                                 opr = new ChengFa();
52                             }
53                             break;
54                         case "/":
55                             {
56                                 opr = new ChuFa();
57                             }
58                             break;
59 
60                         default:
61                             break;
62                     }
63                     opr.NumberA = double.Parse(this.txtshu1.Text.Trim());
64                     opr.NumberB = double.Parse(this.txtshu2.Text.Trim());
65                     this.label2.Text = opr.GetResult().ToString();
66                     this.label1.Visible = true;
67                     this.label2.Visible = true;
68                 }
69                 catch (Exception ex)
70                 {
71                     MessageBox.Show("发生错误！" + ex.Message);
72                 }
73             }
74         }
75 
76 
77     }
78 }

View Code

---------------------------------------------JiaFa类-------------------------------------------------

 1 using System;
 2 using System.Collections.Generic;
 3 using System.Linq;
 4 using System.Text;
 5 using System.Threading.Tasks;
 6 
 7 namespace JiSji
 8 {
 9     /// <summary>
10     /// 加法类
11     /// </summary>
12     public class JiaFa : Operation
13     {
14         public override double GetResult()
15         {
16             double result = NumberA + NumberB;
17             return result;
18         }
19     }
20 
21 
22 }

View Code

---------------------------------------------JianFa类------------------------------------------------

 1 using System;
 2 using System.Collections.Generic;
 3 using System.Linq;
 4 using System.Text;
 5 using System.Threading.Tasks;
 6 
 7 namespace JiSji
 8 {
 9     /// <summary>
10     /// 减法类型
11     /// </summary>
12     public class JianFa : Operation
13     {
14         public override double GetResult()
15         {
16             double result = NumberA - NumberB;
17             return result;
18         }
19     }
20 
21 
22 }

View Code

---------------------------------------------Operation父类------------------------------------------

 1 using System;
 2 using System.Collections.Generic;
 3 using System.Linq;
 4 using System.Text;
 5 using System.Threading.Tasks;
 6 
 7 namespace JiSji
 8 {
 9     /// <summary>
10     /// 父类
11     /// </summary>
12     public class Operation
13     {
14         public double NumberA { get; set; }
15         public double NumberB { get; set; }
16         public virtual double GetResult()
17         {
18             double result = 0;
19             return result;
20         }
21     }
22 
23 
24 }

View Code

---------------------------------------------运行结果------------------------------------------------