A Function can return a value from itself. For example
Public Function Sum(ByVal a As Integer, _
ByVal b As Integer) As Integer
Return a + b
End Function
Then you can use this Function as follows
Dim result As Integer = Sum(2, 4)
On the other hand a Sub can not return a value from itself. It must use a
ByRef parameter to get a result. For example
Public Sub SumSub(ByVal a As Integer, _
ByVal b As Integer) As Integer)
Dim theSum As Integer = a + b
End Sub
This has no way of returning the result and using this like
Dim answer As Integer = SumSub(2, 4)
will generate a complile time error.
We can alter SumSub to take a ByRef parameter.
Public Sub SumSubByRef(ByVal a As Integer, _
ByVal b As Integer) As Integer, ByRef theSum As Integer)
theSum = a + b
End Sub
Then we can do the following
Dim answer As Integer
SumSubByRef(2, 4, answer)
This will get the sum placed into the variable answer.
As you can see, if you are going to be returning a value from your procedure
it is better to write it as a Function rather than a Sub.
Robby
