https://learn.microsoft.com/ja-jp/dotnet/api/system.web.ui.updatepanel.childrenastriggers?view=netframework-4.8.1&redirectedfrom=MSDN
UpdatePanel.ChildrenAsTriggers Property (System.Web.UI) | Microsoft Learn
Gets or sets a value that indicates whether postbacks from immediate child controls of an UpdatePanel control update the panel's content.
property systemweb uimicrosoftlearn