https://learn.microsoft.com/en-us/dotnet/api/system.windows.forms.form.autovalidate?view=netframework-4.8.1&redirectedfrom=MSDN
Form.AutoValidate Property (System.Windows.Forms) | Microsoft Learn
Gets or sets a value that indicates whether controls in this container will be automatically validated when the focus changes.
property systemwindows formsmicrosoftlearn
https://learn.microsoft.com/en-us/dotnet/api/system.windows.forms.usercontrol.autovalidate?view=netframework-4.8.1&tree=cete.dynamicpdf.viewer.pdfnavigationpanel.autovalidate
UserControl.AutoValidate Property (System.Windows.Forms) | Microsoft Learn
Gets or sets how the control performs validation when the user changes focus to another control.
property systemwindows formsmicrosoftlearn