Configuration :: How To Call The "host"setting From The App.config File In C# Code

<configuration>
<system.net>
<mailSettings>
<smtp
from="user@user.com">
<network
host="smtp.server.com"
password="password"
userName="username" />
</smtp>
</mailSettings>
</system.net>
</configuration>

How can I call the "host"setting from the App.config file in my C# code?

I have tried this but it does not work.

SmtpClient mailClient =
new SmtpClient(ConfigurationManager.AppSettings["network"]);