https://learn.microsoft.com/en-us/dotnet/api/system.web.ui.webcontrols.querystringparameter.querystringfield?view=netframework-4.8.1&redirectedfrom=MSDN
QueryStringParameter.QueryStringField Property (System.Web.UI.WebControls) | Microsoft Learn
Gets or sets the name of the query-string field that the parameter binds to.
property systemweb uimicrosoftlearn