System.Web 2.0.0.0 System.Attribute System.AttributeUsage(System.AttributeTargets.Property) The class is used by developers to add design time Cascading Style Sheet (CSS) editing capabilities to a property in a property grid. is introduced in the .NET Framework version 3.5. For more information, see The .NET Framework 3.5 Architecture. Adds Cascading Style Sheet (CSS) editing capabilities to a property at design time. Constructor 2.0.0.0 To be added. Initializes a new instance of the class.