In VB6, you could call this sub in one of two ways:

foo “Hello ”

Call foo(“Hello ”)

In VB.NET, you also could call this sub in one of two ways:

Foo(“Hello ”)

Call foo(“Hello ”)

The difference, of course, is that the parentheses are always required in the VB.NET

calls, even though you aren’t returning anything. The Call statement is still sup-ported,

but it is not really necessary.

Changes to Boolean Operators

The And , Not , and Or operators were to have undergone some changes. Microsoft

originally said that the operators would short-circuit, but now they are staying the

way they worked in VB6. This means that in VB.NET, as in VB6, if you had two

parts of an And statement and the first failed, VB6 still examined the second part.

Examine the following code:

Dim x As Integer

Dim y As Integer

x =1

y =0

If x =2 And y =5/y Then

...

As a human, you know that the variable x is equal to 1 . Therefore, when you look at

the first part of the If statement, you know that x is not equal to 2 , so you would log-ically

think it should quit evaluating the expression. However, VB.NET examines the

second part of the expression, so this code would cause a divide-by-zero error.

If you want short-circuiting, VB.NET has introduced a couple of new operators:

AndAlso and OrElse . In this case, the following code would not generate an error in

VB.NET:

Dim x As Integer

Dim y As Integer

x =1

y =0

If x =2 AndAlso y =5/y Then

...

This code does not cause an error; instead, because x is not equal to 2 , VB.NET does

not even examine the second condition.