How do I find out the value of these dwFlags constants?

How do I find out the value of these dwFlags constants?

I'm looking at the MSDN documentation for ChangeDisplaySettings. For the
dwFlags option, you can pass in 0 or one of the other listed flags.
However, I can't figure out how to reference those flags directly, nor
figure out what their actual long value is to use in their stead.
I'm making these calls from a C# application using this:
[DllImport("User32.dll")]
public static extern long ChangeDisplaySettings(ref DeviceMode lpDevMode,
int dwflags);
Is there a way I can reference the flags directly, or, barring that, find
out what their actual values are?