'宣言 Public Class C1UndoTool Inherits C1ButtonTool Implements IUpdateableTool, Windows.UI.Xaml.Controls.ICommandBarElement, Windows.UI.Xaml.Controls.ICommandBarElement2
public class C1UndoTool : C1ButtonTool, IUpdateableTool, Windows.UI.Xaml.Controls.ICommandBarElement, Windows.UI.Xaml.Controls.ICommandBarElement2