SqlConnection数据库连接类问题

Question

using System;
using System.Collections;
using System.Configuration;
using System.Data;
using System.Linq;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.HtmlControls;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Xml.Linq;
using System.Data.SqlClient;
using System.Data.Sql;
using System.Data.SqlTypes;public partial class shujuku : System.Web.UI.Page
{
    protected void Page_Load(object sender, EventArgs e)
    {    }
    protected void Button1_Click(object sender, EventArgs e)
    {
        string ConnectionString = "data source=.;inital catalog=northwind;user id=sa";
        sqlConnection conn = new sqlConnection(ConnectionString);
        if(conn.state==ConnectionState.Open)
        {
            lblinfo.text = "当前数据库已链接！<br>";
            lblinfo.text += "连接字符串为：" + conn.ConnectionString;
        }
    }
}哪里有错？

Answer 1

sqlConnection conn = new sqlConnection(ConnectionString);
conn.open()
  if(conn.state==ConnectionState.Open)

Answer 2

sqlConnection conn = new sqlConnection(ConnectionString);
conn.open()
  if(conn.state==ConnectionState.Open)

Answer 3

SqlConnection conn = new SqlConnection(""); 
try
{  
conn.Open(); 
}
catch{}
finally  
        {   
            if (conn.State == ConnectionState.Open)   
            {   
                conn.Close();   
            }   
        }