Connection State Problem

Hi to all,
 protected void Page_Load(object sender, EventArgs e)
    {
        try
        {
            Label1.Text = Convert.ToString(DateTime.Now);
            //string con = System.Configuration.ConfigurationSettings.AppSettings["AJS_CMSConnectionString2"];
            ConnectionStringSettings ConstrSettings = ConfigurationManager.ConnectionStrings["AJS_CMSConnectionString2"];
            SqlConnection cn = new SqlConnection(ConstrSettings.ConnectionString);
            if (cn.State == ConnectionState.Open || cn == null || cn.State == ConnectionState.Broken)
            {
                cn.Close();
            }
            cn.Open();
            SqlDataAdapter sda = new SqlDataAdapter("Select * from user_master", cn);
            DataSet ds = new DataSet();
            sda.Fill(ds,"table1");
            GridView1.DataSource = ds.Tables[0];
            GridView1.DataBind();
           
        }
        catch (Exception ex)
        {
            Response.Write(ex.Message);
        }
    }
    protected void Button1_Click(object sender, EventArgs e)
    {
        try
        {
            Label1.Text = Convert.ToString(DateTime.Now);
            //string con = System.Configuration.ConfigurationSettings.AppSettings["AJS_CMSConnectionString2"];
            ConnectionStringSettings ConstrSettings = ConfigurationManager.ConnectionStrings["AJS_CMSConnectionString2"];
            SqlConnection cn = new SqlConnection(ConstrSettings.ConnectionString);
            if (cn.State == ConnectionState.Open || cn == null || cn.State == ConnectionState.Broken)
            {
                cn.Close();
            }
            cn.Open();
            SqlDataAdapter sda = new SqlDataAdapter("Select * from user_master", cn);
            DataSet ds = new DataSet();
            sda.Fill(ds, "table1");
            GridView1.DataSource = ds.Tables[0];
            GridView1.DataBind();

        }
        catch (Exception ex)
        {
            Response.Write(ex.Message);
        }
    }
 
This is my code. During page load i open the connection and read some records from my database, afterwards i click the button and check the connectionstring state now it is closed, my question is why it was closed, i want to set my connectionstring will always opened how to set it ?