dbhelper

using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Threading.Tasks; using System.Data; using System.Data.SqlClient;

namespace 第五章的实例

{  class DBHelp    

{         private SqlConnection con;         public SqlConnection Con        

{             get           

  {                 string sql = "Data Source=.;

Initial Catalog=MySchool;

User ID=sa;Password=131479";                

if (con == null)                

{                     con = new SqlConnection(sql);

                }                

return con;            

}         }         public void Open()        

{             if (con.State == ConnectionState.Closed)            

{                 con.Open();           

  }             else if (con.State == ConnectionState.Broken)          

   {                 con.Close();                 con.Open();          

   }         }         public void Close()       

  {             if (con.State == ConnectionState.Open || con.State == ConnectionState.Broken)        

     {                 con.Close();           

  }       

  }    

} }