Connection String in Web.config File

1. Open Visual Studio
2. Create a New Website
3. Add connection string in Web.config file

<connectionStrings>
<add name="conn" connectionString="Data Source=.\SQLEXPRESS;AttachDbFilename=G:\Asp.net_Controls\App_Data\Database.mdf;Integrated Security=True;User Instance=True" providerName="System.Data.SqlClient"/>
</connectionStrings>


4. Use this connection string in the whole application as below.

Add namespace
using System.Web.Configuration;

And store the connection string in the string variable

static string str = WebConfigurationManager.ConnectionStrings["conn"].ConnectionString;