I define the connection string in either the application config file
(app.config) or the registry and then use a class which exposes a static
method that returns the connection string.

For e.g.

public class Settings
{
    public static ConnectionString
    {
        get
        {
            //Get the connection string either by using registry or by
using ConfigurationSettings.AppSettings class
        }
    }
}

Now in all the classes where i need a connection i simply use

SqlConnection conn = new SqlConnection(Settings.ConnectionString);

Sijin Joseph
http://www.indiangeek.net
http://weblogs.asp.net/sjoseph