利用SqlCommand和SqlDataReader对象操作数据库

  
    

   
     using
   
      System;
 2
   
     using
   
      System.Data;
 3
   
     using
   
      System.Configuration;
 4
   
     using
   
      System.Collections;
 5
   
     using
   
      System.Web;
 6
   
     using
   
      System.Web.Security;
 7
   
     using
   
      System.Web.UI;
 8
   
     using
   
      System.Web.UI.WebControls;
 9
   
     using
   
      System.Web.UI.WebControls.WebParts;
10
   
     using
   
      System.Web.UI.HtmlControls;
11
   
     using
   
      System.Data.SqlClient; 
   
     //
   
     added by zhangq
   
     

   
     12
   
     
13
   
     public
   
      
   
     partial
   
      
   
     class
   
      TestDB : System.Web.UI.Page

   
     14
   
     {

   
     15
   
      
   
     private
   
      
   
     void
   
      ReadSingleResult()

   
     16
   
      {

   
     17
   
      
   
     //
   
     创建数据连接
   
     

   
     18
   
      
   
     //
   
     从文件web.config中读取数据库链接字符串
   
     

   
     19
   
      
   
     string
   
      conString 
   
     =
   
      ConfigurationManager.ConnectionStrings[
   
     "
   
     DBTESTConnectionString
   
     "
   
     ].ConnectionString;

   
     20
   
      SqlConnection myCon 
   
     =
   
      
   
     new
   
      SqlConnection(conString);

   
     21
   
     

   
     22
   
      
   
     //
   
     创建执行命令
   
     

   
     23
   
      SqlCommand myCmd 
   
     =
   
      
   
     new
   
      SqlCommand(
   
     "
   
     SELECT TOP 3 * FROM 仓库 ORDER BY 仓库号 DESC
   
     "
   
     , myCon);

   
     24
   
     

   
     25
   
      
   
     //
   
     定义dr
   
     

   
     26
   
      SqlDataReader dr 
   
     =
   
      
   
     null
   
     ;

   
     27
   
      
   
     try
   
     

   
     28
   
      {

   
     29
   
      myCon.Open(); 
   
     //
   
     打开数据库的链接
   
     

   
     30
   
      dr 
   
     =
   
      myCmd.ExecuteReader();

   
     31
   
      ShowData(dr);

   
     32
   
      dr.Close();

   
     33
   
      }

   
     34
   
      
   
     catch
   
      (Exception ex) { Response.Write(ex.Message); }

   
     35
   
      
   
     finally
   
     

   
     36
   
      {

   
     37
   
      myCon.Close();

   
     38
   
      }

   
     39
   
      }

   
     40
   
      
   
     private
   
      
   
     void
   
      ShowData(SqlDataReader dr)

   
     41
   
      {

   
     42
   
      String str 
   
     =
   
      
   
     ""
   
     ;

   
     43
   
      
   
     for
   
      (
   
     int
   
      i 
   
     =
   
      
   
     0
   
     ; i 
   
     <
   
      dr.FieldCount; i
   
     ++
   
     )

   
     44
   
      {

   
     45
   
      str 
   
     =
   
      str 
   
     +
   
      dr.GetName(i);

   
     46
   
      }

   
     47
   
      str 
   
     =
   
      str 
   
     +
   
      
   
     "
   
     <br>
   
     "
   
     ;

   
     48
   
      
   
     while
   
      (dr.Read())

   
     49
   
      {

   
     50
   
      
   
     for
   
      (
   
     int
   
      i 
   
     =
   
      
   
     0
   
     ; i 
   
     <
   
      dr.FieldCount; i
   
     ++
   
     )

   
     51
   
      {

   
     52
   
      str 
   
     =
   
      str 
   
     +
   
      dr[i].ToString();

   
     53
   
      }

   
     54
   
      }

   
     55
   
      Response.Write(str);

   
     56
   
      }

   
     57
   
      
   
     protected
   
      
   
     void
   
      Page_Load(
   
     object
   
      sender, EventArgs e)

   
     58
   
      {

   
     59
   
      ReadSingleResult();

   
     60
   
      }

   
     61
   
     }