You don't need LINQ or a ternary operator. All you need is
_parentForm.CheckMenu(MenuEnabled);
[Edit]
The above comment is true and answers your question but I am concerned about the way you have written these statements - may as well learn this now before you get into bad habits :)
You don't need to use
== false
or
== true
when using Booleans. Just use (for == true)
if (MenuEnabled)
and (for == false)
if (!MenuEnabled)
Also you don't need the
if ... else if
with bools - they can only be true or false so there is no need for the second
if