https://learn.microsoft.com/en-us/dotnet/api/system.web.ui.webcontrols.loginname?view=netframework-4.8.1&redirectedfrom=MSDN
LoginName Class (System.Web.UI.WebControls) | Microsoft Learn
Displays the value of the System.Web.UI.Page.User.Identity.Name property.
class systemweb uimicrosoftlearn