The IsProtected property will return true if the Workbook is currently protected. When a Workbook is protected certain operations related to the Worksheets displayed or their order or the properties of the windows for the Workbook may be restricted based on the values of the Protection.
Target Platforms: Android 4.4+, iOS 8+
Development Environments: Visual Studio 2015+, Visual Studio for Mac Preview, Xamarin for Visual Studio 4.2+