Table是怎样炼成的：SaleReport Table的继承者

有了Table，我们对其继承，实现更符合业务要求的类

1 /**//// <summary>
2 /// 描述一个销售报表
3 /// </summary>
4 public class SaleReport : Table
5 {
6
7 public SaleReport(string reportName)
8 : base(reportName, new ColumnCollection())
9 {
10
11 this.Columns.Add("序号", typeof(int), 0);
12 this.Columns.Add("姓名", typeof(string), null);
13 this.Columns.Add("商品名称", typeof(string), null);
14 this.Columns.Add("日期", typeof(DateTime), null);
15 this.Columns.Add("数量", typeof(double), null);
16 }
17
18 /**//// <summary>
19 /// 报表的名称
20 /// </summary>
21 public string Name
22 {
23 get
24 {
25 return this.Name;
26 }
27 }
28
29 /**//// <summary>
30 /// 加入数据
31 /// </summary>
32 /// <param name="staff"></param>
33 /// <param name="commodity"></param>
34 /// <param name="cash"></param>
35 public void AddRecord(string staff, string commodity, double cash)
36 {
37 Row row = this.NewRow();
38 row["序号"] = this.Rows.Count + 1;
39 row["姓名"] = staff;
40 row["商品名称"] = commodity;
41 row["日期"] = DateTime.Now;
42 row["数量"] = cash;
43
44 this.Rows.Add(row);
45 }
46
47 /**//// <summary>
48 /// 移除数据
49 /// </summary>
50 /// <param name="index"></param>
51 public void RemoveAt(int index)
52 {
53 this.Rows.RemoveAt(index);
54 }
55
56 /**//// <summary>
57 /// 返回销售报表的销售金额
58 /// </summary>
59 /// <returns></returns>
60 public double GetTotal()
61 {
62 double cash = 0;
63 foreach (Row row in this.Rows)
64 {
65 cash += (double)row["数量"];
66 }
67 return cash;
68 }
69
70 /**//// <summary>
71 /// 返回销售报表的销售金额
72 /// </summary>
73 /// <param name="staff">销售员</param>
74 /// <returns></returns>
75 public double GetTotal(string staff)
76 {
77 double cash = 0;
78 foreach (Row row in this.Rows)
79 {
80 if ((string)row["姓名"] == staff)
81 {
82 cash += (double)row["数量"];
83 }
84 }
85 return cash;
86 }
87
88 }

SaleReport对外封装了对Table的处理细节，使用SaleReport的用户不会感觉到在使用Table类

1 SaleReport report = new SaleReport("销售台帐");
2 report.AddRecord("Alex", "Phone", 2600);
3 report.AddRecord("Alex", "PC", 4560);
4 report.AddRecord("Alex", "Table", 234);
5 report.AddRecord("Sidney", "Phone", 2100);
6 report.AddRecord("Sidney", "TV", 4500);
7 report.AddRecord("Tom", "oven", 300);
8 report.AddRecord("Leo", "oven", 240);
9
10 report.Print();

运行的结果是
序号 姓名 商品名称 日期 数量

1 Alex Phone 2007-2-13 23:19:27 2600
2 Alex PC 2007-2-13 23:19:27 4560
3 Alex Table 2007-2-13 23:19:27 234
4 Sidney Phone 2007-2-13 23:19:27 2100
5 Sidney TV 2007-2-13 23:19:27 4500
6 Tom oven 2007-2-13 23:19:27 300
7 Leo oven 2007-2-13 23:19:27 240