Is there a VB.net equivalent for C#'s ! operator?

Question

After two years of C#, I\'m now back to VB.net because of my current job. In C#, I can do a short hand testing for null or false value on a string variable like this:

<

Answer 1

Yes they are the same

Answer 2

They work identically until you reference C or C++ code.

For example doing NOT on the result of a Win32 API function, might lead to incorrect result, since true in C == 1, and a bitwise NOT on 1 does not equal false.

As 1 is        00000000001
Bitwise Not    11111111110
While false is 00000000000

However in VB it works just fine, as in VB true == -1

As -1 is       11111111111
Bitwise Not    00000000000

Answer 3

c# : boolean example1 = false;

 boolean example2 = !example1;

vb.net: dim example1 as boolean = False

    dim example2 as boolean = Not example1

Answer 4

Seconded. They work identically. Both reverse the logical meaning of the expression following the !/not operator.

Answer 5

Not is exactly like ! (in the context of Boolean. See RoadWarrior's remark for its semantics as one's complement in bit arithmetic). There's a special case in combination with the Is operator to test for reference equality:

If Not x Is Nothing Then ' … '
' is the same as '
If x IsNot Nothing Then ' … '

is equivalent to C#'s

if (x != null) // or, rather, to be precise:
if (object.ReferenceEquals(x, null))

Here, usage of IsNot is preferred. Unfortunately, it doesn't work for TypeOf tests.

Answer 6

In the context you show, the VB Not keyword is indeed the equivalent of the C# ! operator. But note that the VB Not keyword is actually overloaded to represent two C# equivalents:

• logical negation: !
• bitwise complement: ~

For example, the following two lines are equivalent:

• C#: useThis &= ~doNotUse;
• VB: useThis = useThis And (Not doNotUse)