ASP.NET中操作SQL数据库

在webconfig中配置连接字符串，代码如下：

<connectionstrings>
        <add name="connectionstring" connectionstring="user id=用户名;password=密码;initial catalog=数据库名称;data source=服务器名称"/>
  </connectionstrings>

然后在webform_1.x.cs里面获取连接字符串，要添加如下引用；

using system.configuration;
using system.data;
using system.data.sqlclient;

代码：

sqlconnection con;

        protected void page_load(object sender, eventargs e)
        {
            connectdb();
        }

private void connectdb()
        {
            string constring = configurationmanager.connectionstrings["connectionstring"].connectionstring;
            con = new sqlconnection(constring);
            con.open();
            sqlcommand com = new sqlcommand();
            sqldatareader sdr;
            string sqlstr = "select * from item";
            com.commandtext = sqlstr;
            com.connection = con;
            sdr = com.executereader();
            while (sdr.read())
            {
                response.write(sdr["字段名"].tostring()+"</br>");
            }
            sdr.close();
            sdr = null;
           
        }