//连接字符串_直接写
string conStr = "Data Source=computer;Initial Catalog=AdoTest;Integrated Security=True; Persist Security Info=True;";

//连接字符串_写在Web.Config里
string conStr = System.Configuration.ConfigurationManager.ConnectionStrings["constring"].ToString();
//Web.Config里设置
<connectionStrings>
    <add name="constring" connectionString="Data Source=visingcomputer;Initial Catalog=AdoTest;Integrated Security=True; Persist Security Info=True;"/>
  </connectionStrings>

//连接数据库
        string conStr =System.Configuration.ConfigurationManager.ConnectionStrings[1].ToString();
        SqlConnection sqlCon = new SqlConnection(conStr);
        sqlCon.Open();
        this.Label1.Text = sqlCon.State.ToString();

        //插入数据
        string sqlIntoCmd="insert into info values('123','地理学','g')";
        SqlCommand sqlInto = new SqlCommand(sqlIntoCmd, sqlCon); 
        sqlInto.ExecuteNonQuery();  //这句执行后,数据才真正插入数据库中.

        ////使用SqlDataReader显示数据
        //string sqlSelectCmd = "select * from info";
        //SqlCommand sqlSelect = new SqlCommand(sqlSelectCmd, sqlCon);
        //SqlDataReader sqlDr=sqlSelect.ExecuteReader();
        //while (sqlDr.Read())
        //{
        //    Response.Write(sqlDr[0]);
        //    Response.Write(sqlDr[1]);
        //    Response.Write(sqlDr[2]);
        //    Response.Write("<br />");
        //}
        //sqlDr.Close();


        //使用SqlDataAdapter,DataSet显示数据
        string sqlSelectCmd = "select * from info";
        SqlDataAdapter da = new SqlDataAdapter(sqlSelectCmd, sqlCon);        
        DataSet ds = new DataSet();
        da.Fill(ds, "info");
        if (ds.Tables[0].Rows.Count == 0)
        {
            Response.Write("NOdata");
        }
        else
        {
            for (int i = 0; i < ds.Tables[0].Rows.Count; i++)
            {
                Response.Write(ds.Tables[0].Rows[i][0]);
                Response.Write(ds.Tables[0].Rows[i][1]);
                Response.Write(ds.Tables[0].Rows[i][2]);
                Response.Write("<br />");
            }            
        }
       

        ////使用SqlDataAdapter,SqlCommandBuilder,DataSet插入数据
        //string sqlSelectCmd = "select * from info";        
        //SqlDataAdapter da = new SqlDataAdapter(sqlSelectCmd, sqlCon);
        //SqlCommandBuilder cb = new SqlCommandBuilder(da);
        //DataSet ds = new DataSet();
        //da.Fill(ds, "info");
        //DataRow newrow = ds.Tables[0].NewRow();
        //newrow[0] = "text";
        //newrow[1] = "text";
        //newrow[2] = "text";
        //ds.Tables[0].Rows.Add(newrow);
        //da.Update(ds, "info");

        sqlCon.Close();