第六章，上机4

 1 using System;
 2 using System.Collections.Generic;
 3 using System.Linq;
 4 using System.Text;
 5 using System.Threading.Tasks;
 6
 7 namespace Shangji_4
 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 }

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 Shangji_4
 8 {
 9     class Additive:Operation
10     {
11         public override double GetResult()
12         {
13             double result = NumberA + NumberB;
14             return result;
15         }
16     }
17 }

加法类

 1 using System;
 2 using System.Collections.Generic;
 3 using System.Linq;
 4 using System.Text;
 5 using System.Threading.Tasks;
 6
 7 namespace Shangji_4
 8 {
 9     class Subtraction:Operation
10     {
11         public override double GetResult()
12         {
13             double result = NumberA - NumberB;
14             return result;
15         }
16     }
17 }

减法类

 1 using System;
 2 using System.Collections.Generic;
 3 using System.Linq;
 4 using System.Text;
 5 using System.Threading.Tasks;
 6
 7 namespace Shangji_4
 8 {
 9     class Multiplication:Operation
10     {
11         public override double GetResult()
12         {
13             double result = NumberA * NumberB;
14             return result;
15         }
16     }
17 }

乘法类

 1 using System;
 2 using System.Collections.Generic;
 3 using System.Linq;
 4 using System.Text;
 5 using System.Threading.Tasks;
 6
 7 namespace Shangji_4
 8 {
 9     class Division:Operation
10     {
11         public override double GetResult()
12         {
13             if (NumberB == 0)
14             {
15                 throw new Exception("除数不能为0");
16             }
17             double result = NumberA / NumberB;
18             return result;
19         }
20     }
21 }

除法类

 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 Shangji_4
12 {
13     public partial class MainFrm : Form
14     {
15         public MainFrm()
16         {
17             InitializeComponent();
18             this.cmbOperator.SelectedIndex = 0;
19         }
20
21         private void btnArithmetic_Click(object sender, EventArgs e)
22         {
23             //验证
24             //txtNo使是用户输入的操作数
25             if (string.IsNullOrEmpty(this.txtNo1.Text.Trim()) || string.IsNullOrEmpty(this.txtNo2.Text.Trim()) || string.IsNullOrEmpty(this.cmbOperator.Text.Trim()))
26             {
27                 MessageBox.Show("操作数不能为空！");
28                 return;
29             }
30             //设置符号
31             try
32             {
33                 Operation opr = new Operation();
34                 switch (this.cmbOperator.SelectedItem.ToString())
35                 {
36                     case "+":
37                         opr = new Additive();
38                         break;
39                     case "-":
40                         opr = new Subtraction();
41                         break;
42                     case "*":
43                         opr = new Multiplication();
44                         break;
45                     case "/":
46                         opr = new Division();
47                         break;
48                 }
49                 //设置参与计算的数据
50                 opr.NumberA = double.Parse(this.txtNo1.Text.Trim());
51                 opr.NumberB = double.Parse(this.txtNo2.Text.Trim());
52                 //计算
53                 this.lblResult.Text = opr.GetResult().ToString();
54                 this.label1.Visible = true;
55                 this.lblResult.Visible = true;
56             }
57             catch (Exception)
58             {
59
60                 throw;
61             }
62         }
63
64     }
65 }

Main