C# - Connection String using Webconfig and Manual

//Conection
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Data.SqlClient;
using System.Configuration;
using System.Data;
namespace DAL
{
    public class Connection
    {
        #region Methods
        public static SqlConnection conn;

        public static void OpenConnection()
        {
            try
            {
                //SQL Connection Initialize using Manual Connection
                conn = new SqlConnection("Server=(local); Database=CRUD; Integrated Security=true");
        //SQL Connection Initialize using Web Config Connection
        conn = new SqlConnection(ConfigurationManager.ConnectionStrings["ConnectionStringName"].ToString());
                conn.Open();
            }
            catch
            {

            }
        }

        public static void CloseConnection()
        {
            try
            {
                //SQL Close Connection Initialize
                if (conn != null)
                {
                    if (conn.State == ConnectionState.Open)
                    {
                        conn.Close();
                    }
                }

            }
            catch
            {

            }
        }
        #endregion
    }
}


<connectionStrings>
<add name="conn" connectionString="Data Source=coolxpc\\SQLEXPRESS;Initial Catalog=db_deneme;uid=sa;pwd=12345";Integrated Security=False;MultipleActiveResultSets=False;Packet Size=4096;Application Name=&quot;Microsoft SQL Server Management Studio Express&quot;" providerName="System.Data.SqlClient"/>

</connectionStrings>

//Web Config Part
<add name="ConnectionStringName"  connectionString=YourServer"; Initial Catalog=YourDB; Integrated Security=True"/>