https://learn.microsoft.com/zh-cn/dotnet/api/system.windows.iinputelement.previewstylusdown?view=netframework-4.8.1&viewFallbackFrom=windowsdesktop-10.0
IInputElement.PreviewStylusDown Event (System.Windows) | Microsoft Learn
Occurs when the stylus touches the digitizer while over this element.
event systemwindowsmicrosoftlearn