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

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/**//// <summary>
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/// 描述一个销售报表
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/// </summary>
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public class SaleReport : Table
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{
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public SaleReport(string reportName)
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: base(reportName, new ColumnCollection())
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{
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this.Columns.Add("序号", typeof(int), 0);
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this.Columns.Add("姓名", typeof(string), null);
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this.Columns.Add("商品名称", typeof(string), null);
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this.Columns.Add("日期", typeof(DateTime), null);
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this.Columns.Add("数量", typeof(double), null);
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}
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/**//// <summary>
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/// 报表的名称
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/// </summary>
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public string Name
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{
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get
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{
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return this.Name;
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}
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}
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/**//// <summary>
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/// 加入数据
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/// </summary>
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/// <param name="staff"></param>
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/// <param name="commodity"></param>
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/// <param name="cash"></param>
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public void AddRecord(string staff, string commodity, double cash)
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{
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Row row = this.NewRow();
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row["序号"] = this.Rows.Count + 1;
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row["姓名"] = staff;
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row["商品名称"] = commodity;
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row["日期"] = DateTime.Now;
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row["数量"] = cash;
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this.Rows.Add(row);
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}
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/**//// <summary>
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/// 移除数据
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/// </summary>
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/// <param name="index"></param>
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public void RemoveAt(int index)
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{
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this.Rows.RemoveAt(index);
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}
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/**//// <summary>
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/// 返回销售报表的销售金额
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/// </summary>
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/// <returns></returns>
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public double GetTotal()
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{
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double cash = 0;
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foreach (Row row in this.Rows)
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{
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cash += (double)row["数量"];
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}
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return cash;
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}
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/**//// <summary>
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/// 返回销售报表的销售金额
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/// </summary>
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/// <param name="staff">销售员</param>
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/// <returns></returns>
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public double GetTotal(string staff)
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{
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double cash = 0;
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foreach (Row row in this.Rows)
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{
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if ((string)row["姓名"] == staff)
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{
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cash += (double)row["数量"];
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}
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}
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return cash;
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}
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}

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

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SaleReport report = new SaleReport("销售台帐");
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report.AddRecord("Alex", "Phone", 2600);
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report.AddRecord("Alex", "PC", 4560);
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report.AddRecord("Alex", "Table", 234);
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report.AddRecord("Sidney", "Phone", 2100);
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report.AddRecord("Sidney", "TV", 4500);
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report.AddRecord("Tom", "oven", 300);
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report.AddRecord("Leo", "oven", 240);
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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