在操作数据库时，将数据方法封装为不同类，增加程序的可读性

提供数据连接对象的类

1 using System; 2 using System.Collections.Generic; 3 using System.Linq; 4 using System.Text; 5 using System.Threading.Tasks; 6 using System.Data.SqlClient; 7  8 namespace ConsoleApplication1 9 {10     //提供数据连接对象11     public class DBConnect12     {13         private static string connstring = "server=.;database=mydb;user=sa;pwd=123";14 15         public static SqlConnection Conn16         {17             get {18                 return new SqlConnection(connstring);19             }20         }21     }22 }

建立属性

1 using System; 2 using System.Collections.Generic; 3 using System.Linq; 4 using System.Text; 5 using System.Threading.Tasks; 6  7 namespace ConsoleApplication1 8 { 9     public class Nation10     {11         private string code;12 13         public string Code14         {15             get { return code; }16             set { code = value; }17         }18         private string name;19 20         public string Name21         {22             get { return name; }23             set { name = value; }24         }25     }26 }

封装运算方法

1 using System; 2 using System.Collections.Generic; 3 using System.Linq; 4 using System.Text; 5 using System.Threading.Tasks; 6 using System.Data.SqlClient; 7  8 namespace ConsoleApplication1 9 {10     //主要实现对Nation表的各种操作（增删改查）11     public class NationDA12     {13         private SqlConnection _conn; //连接对象14         private SqlCommand _cmd; //命令对象15         private SqlDataReader _dr; //读取器对象16 17         //构造方法来初始化连接对象 命令对象18         public NationDA()19         {20             _conn = DBConnect.Conn; //对连接对象进行初始化21             _cmd = _conn.CreateCommand(); //对命令对象进行初始化22         }23 24         //添加数据的方法25         public bool Add(string code,string name)26         {27             _cmd.CommandText = "insert into Nation values(@code,@name)";28             _cmd.Parameters.AddWithValue("@code",code);29             _cmd.Parameters.AddWithValue("@name",name);30 31             _conn.Open();32             int n = _cmd.ExecuteNonQuery();33             _conn.Close();34 35             if (n > 0)36             {37                 return true;38             }39             else40             {41                 return false;42             }43         }44 45         //查询所有数据的方法46         public List
     
       Select()47         {48             _cmd.CommandText = "select * from Nation";49             _conn.Open();50             _dr = _cmd.ExecuteReader();51             _conn.Close();52 53             //定义一个空的集合54             List
      
        list = new List
       
        ();55 56             if (_dr.HasRows)57             {58                 while (_dr.Read())59                 {60                     //造一个Nation对象61                     Nation data = new Nation();62                     data.Code = _dr[0].ToString();63                     data.Name = _dr[1].ToString();64 65                     //扔到集合里面66                     list.Add(data);67                 }68             }69 70             return list;71         }72     }73 }
       
      
     

主函数调用

1 using System; 2 using System.Collections.Generic; 3 using System.Linq; 4 using System.Text; 5 using System.Threading.Tasks; 6  7 namespace ConsoleApplication1 8 { 9     class Program10     {11         static void Main(string[] args)12         {13             Console.WriteLine("请输入代号：");14             string code = Console.ReadLine();15 16             Console.WriteLine("请输入名称：");17             string name = Console.ReadLine();18 19             NationDA da = new NationDA();20 21             if (da.Add(code, name))22             {23                 Console.WriteLine("添加成功！");24             }25             else26             {27                 Console.WriteLine("添加失败！");28             }29 30 31             Console.ReadLine();32         }33     }34 }