https://learn.microsoft.com/ja-jp/dotnet/api/system.windows.controls.primitives.textboxbase.isreadonlycaretvisible?view=netframework-4.8.1
TextBoxBase.IsReadOnlyCaretVisible Property (System.Windows.Controls.Primitives) | Microsoft Learn
Gets or sets a value that indicates whether a read-only text box displays a caret.
property systemwindowscontrolsprimitivesmicrosoft