Detecting Web.Config Authentication Mode

<?xml version="1.0" encoding="utf-8"?>
<configuration>
	<system.web>
		<authentication mode="Windows"></authentication>
	</system.web>
</configuration>

// Get the current Mode property.
AuthenticationMode currentMode =
    authenticationSection.Mode;

// Set the Mode property to Windows.
authenticationSection.Mode =
    AuthenticationMode.Windows;

var configuration = WebConfigurationManager.OpenWebConfiguration("/");
var authenticationSection = (AuthenticationSection)configuration.GetSection("system.web/authentication");
if (authenticationSection.Mode == AuthenticationMode.Forms)
{
  //do something
}

protected void Page_Load(object sender, EventArgs e)
{
 XmlDocument config = new XmlDocument();
 config.Load(AppDomain.CurrentDomain.SetupInformation.ConfigurationFile);
 XmlNode node = config.SelectSingleNode("//configuration/system.web/authentication");
 this.Label1.Text = node.Attributes["mode"].Value;
}