C# If not (this) Or (this) or (this) - Multiple condition IF/OR

c# if-statement multiple-conditions
bairdmar picture bairdmar · Sep 19, 2016 · Viewed 14.7k times · Source

I have a condition like:

 if (!(InRange1 || InRange2 || InRange3))
{
//Do Something
}

Each of the InRange Variables are boolean.

The desired behavior is if anyone of those values is False I want to do something, but it is not working that way. All of the values have to be false before the event is triggered.

Does it need to be written as 

if (!InRange1 || !InRange2 || !InRange3)
{
//do something
}

And, in either case I'm curious why the original statement doesn't work.

Answer

EJoshuaS - Reinstate Monica picture EJoshuaS - Reinstate Monica · Sep 19, 2016

You can use DeMorgan's Law for this.

What you have is equivalent to NOR. !(A | B | C) is equivalent to !A & !B & !C by DeMorgan's Law.

What you want is NAND, so !(A && B && C). This is exactly equivalent to what you're looking for - !A | !B | !C.

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