How is check the date of a valid dateEdit ?

Question

2 assume their respective control dateEdit: dEditForm and dEditTo want to check the date of this control has the form 2: date from: "__ / __ / ____" and date to: 11/09/2016, which from day null and days to 1 day, must be valid as examples here dates are September 11 years his 2016 writing test code with the error message:

[CODE]

if (dEditFrom.DateTime == null && dEditTo.DateTime != null) // warning error here dEditTo.DateTime != null

{ do something ... }

[/CODE]

I using devexpress. can you help me ?