ADO.NET中的ExecuteNonQuery()方法、ExecuteReader()方法、ExecuteScalar()方法使用小实例

EcecuteNonQuery()方法

using System;using System.Data;using System.Configuration;using System.Web;using System.Web.Security;using System.Web.UI;using System.Web.UI.WebControls;using System.Web.UI.WebControls.WebParts;using System.Web.UI.HtmlControls;using System.Data.SqlClient;public partial class _Default : System.Web.UI.Page{    protected void Page_Load(object sender, EventArgs e)    {    }    protected void Button1_Click(object sender, EventArgs e)    {        SqlConnection conn = new SqlConnection("server=JMENG//TING;database=db_LQ;uid=sa;pwd=1");        SqlCommand cmd = new SqlCommand();        string sqlText = "update tb_admin set adminName = 'xx' where adminName = 'admin'";        cmd.CommandText = sqlText;        cmd.Connection = conn;        try        {            //打开数据库            conn.Open();            //ExecuteNonQuery()方法的使用(用于执行无返回值的数据库操作，            //即对Connection执行T-SQL语句（如UPDATA、INSERT、DELETE）)            int num;            num = cmd.ExecuteNonQuery();            //输出            Response.Write("你修改" + num + "条数据");        }        catch        {            Response.Write("数据库连接失败");        }        finally        {            conn.Close();        }    }}

ExecuteReader()方法

using System;using System.Data;using System.Configuration;using System.Web;using System.Web.Security;using System.Web.UI;using System.Web.UI.WebControls;using System.Web.UI.WebControls.WebParts;using System.Web.UI.HtmlControls;using System.Data.SqlClient;public partial class _Default : System.Web.UI.Page {    protected void Page_Load(object sender, EventArgs e)    {    }    protected void Button1_Click(object sender, EventArgs e)    {        SqlConnection conn = new SqlConnection("server=JMENG//TING;database=db_LQ;uid=sa;pwd=1");        SqlCommand cmd = new SqlCommand();        cmd.CommandText = "select * from tb_admin";        cmd.Connection = conn;        try        {            conn.Open();            //数据集对象            SqlDataReader r = cmd.ExecuteReader();            //数据集遍历            while (r.Read() == true)            {                this.ListBox1.Items.Add("adminName = " + r[0].ToString() + "adminPwd = " +r[1].ToString());            }            r.Close();        }        catch        {            Response.Write("失败");        }        finally        {            conn.Close();        }    }}

ExecuteScalar()方法

using System;using System.Data;using System.Configuration;using System.Web;using System.Web.Security;using System.Web.UI;using System.Web.UI.WebControls;using System.Web.UI.WebControls.WebParts;using System.Web.UI.HtmlControls;using System.Data.SqlClient;public partial class _Default : System.Web.UI.Page {    protected void Page_Load(object sender, EventArgs e)    {    }    protected void Button1_Click(object sender, EventArgs e)    {        SqlConnection cn = new SqlConnection("server=JMENG//TING;database=db_LQ;uid=sa;pwd=1");        SqlCommand cmd = new SqlCommand();        cmd.CommandText = "select count(*) from tb_admin where adminPassword = 'zhang'";        cmd.Connection = cn;        try        {            cn.Open();            int count = Convert.ToInt32(cmd.ExecuteScalar());            Response.Write("有zhang的个数为" + count + ".");        }        catch        {            Response.Write("没有！");        }        finally        {            cn.Close();        }    }}