The Equality method defines the equality operator for Double values.
If two Double.NaN values are tested for equality by using the equality operator, the result is false; two Double.NaN values are not considered equal. If they are tested for equality by calling the Equals method, the result is true. When you want to determine whether the value of a Double is not a number (NaN), an alternative is to call the IsNaN method.
Windows Phone 8.1, Windows Phone 8, Windows 8.1, Windows Server 2012 R2, Windows 8, Windows Server 2012, Windows 7, Windows Vista SP2, Windows Server 2008 (Server Core Role not supported), Windows Server 2008 R2 (Server Core Role supported with SP1 or later; Itanium not supported)