Writing Connection string in web.config file

In Web.config file

<appsettings><add key="sqlconstrusingappset" value="server=FOCALPOI-392A7D\SQLEXPRESS;user id=raji;password=chekuri;database=raji"> </add></appsettings> <connectionstrings> <add connectionstring="server=FOCALPOI-392A7D\SQLEXPRESS;user id=raji;password=chekuri;database=raji" name="sqlconstr"> </add></connectionstrings>

In .CS file

string str = ConfigurationManager.ConnectionStrings["sqlconstr"].ToString();

string str1 = ConfigurationManager.AppSettings[0].ToString();

or

string str1 = ConfigurationManager.AppSettings["sqlconstrusingappset"].ToString();

//connection string using ConnectionString

con = new SqlConnection(str);

or

//connection string using AppSettings

con = new SqlConnection(str1);

con.Open();