This enumeration is used throughout the framework to specify which mouse buttons are currently pressed. It is decorated with the FlagsAttribute , so the values may be combined with one of the logical operators (and you should test with the & operator rather than simple equality, as more than one bit may be set). public enum MouseButtons { None = 0x00000000 , Left = 0x00100000 , Right = 0x00200000 , Middle = 0x00400000 , XButton1 = 0x00800000 , XButton2 = 0x01000000 } HierarchySystem.Object System.ValueType System.Enum(System.IComparabl, System.IFormattable , System.IConvertible) MouseButtons Returned ByControl.MouseButtons , ItemDragEventArgs.Button , MouseEventArgs.Button Passed ToItemDragEventArgs.ItemDragEventArgs() , MouseEventArgs.MouseEventArgs() , StatusBarPanelClickEventArgs.StatusBarPanelClickEventArgs() |