In Web.config under <configuration> Tag
<connectionStrings>
<add name="ConnStringDb1" connectionString="Data Source=localhost;Initial Catalog=YourDataBaseName;Integrated Security=True;" providerName="System.Data.SqlClient" />
</connectionStrings>
in C# code usage
SqlCommand command; public static string connectionstring = ConfigurationManager.ConnectionStrings["ConnStringDb1"].ToString(); SqlConnection conn = new SqlConnection(connectionstring);
Dont Forget to add "using System.Configuration;"
