N种连接SQL数据库方式

DB.CS类：

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;

/**//// <summary>
/// DB 的摘要说明
/// </summary>
public class DB
...{
    public DB()
    ...{
        //
        // TODO: 在此处添加构造函数逻辑
        //
    }
    public static SqlConnection createCon()
    ...{
        return new SqlConnection("server=(local);database=blog;UId=sa;password=123456;");
    }


}

Web.config文件:

<appSettings>
<add key="ConnectionString" value="server=(local);database=blog;UId=sa;password=123456;"/>    
</appSettings>

.CS文件

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)
    ...{
        //string strConnnection = ConfigurationManager.AppSettings["ConnectionString"];
        //SqlConnection myconn = new SqlConnection(strConnnection);
        //SqlDataAdapter mycmd1 = new SqlDataAdapter("select * from contents order by shijian desc", myconn);
        SqlConnection con = DB.createCon();//建立连接
        SqlDataAdapter sda = new SqlDataAdapter();//实例化适配器
        sda.SelectCommand = new SqlCommand("select * from contents order by shijian desc", con);
        DataSet ds = new DataSet();
        sda.Fill(ds, "contents");
        this.GridView1.DataSource = ds.Tables["contents"].DefaultView;
        this.GridView1.DataBind();
        this.bind();
           
    }