cannot explicit convert double.MaxValue/double.MinValue/float.MaxValue/float.MinValue to decimal

I'm try set double.MaxValue/double.MinValue/float.MaxValue/float.MinValue to NumericUpDown's Maximun/Minimum

It fail (compile error)

but variable and constant's explicit conversion is OK.

can anyone tell me why?

the screenshot is in below

http://ift.tt/18nTVWD