Use CharCase to force the contents of the edit control to assume a particular case. 

When CharCase is set to ecLowerCase or ecUpperCase, the case of characters is converted as the user types them into the edit control. Changing the CharCase property to ecLowerCase or ecUpperCase changes the actual contents of the text, not just the appearance. Any case information is lost and can’t be recaptured by changing CharCase to ecNormal.

TEditEx Properties