Sock.GetData (Data)
Quote:
Originally Posted by
List1.AddItem (Data)
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You already have your answer to the question you asked; however, I wanted to
point something out about the above two lines of code from your posting. Get
out of the habit you apparently have of encasing arguments for methods and,
I will guess by extension, subroutine calls in parentheses. Unlike other
languages which **require** parentheses around all arguments, VB doesn't. In
the above statements, it won't cause any problem; but there are cases where
surrounding your arguments in parentheses will cause an error to occur or,
worse yet, no error will be generated but incorrect results will be
generated. You should only use parentheses around arguments where they are
required **by syntax**. For arguments to methods (such as above),
parentheses are never required; for subroutines, they are required only when
the CALL keyword is used to call the subroutine.
The reason for my caution is that VB treats things in parentheses as
expressions to be evaluated (even if that thing is not really considered an
expression, such as a variable name). If your method or subroutine call
require two arguments, encasing both of them in one set of parentheses will
force an error to be generated as a comma separated list is not a proper
expression that VB can evaluate. The real problem comes with arguments that
are supposed to be passed ByRef (by reference)... a parentheses-encased
argument will force VB to pass the memory address of the temporary memory
location used to evaluate the expression and that is what the subroutine
will use to write back its ByRef argument to... which means the original
variable which was supposed to be updated by the subroutine will not be (no
error will be generated, but your results will be incorrect). Here is a
short example to show you what I mean. Paste the following into new
project's Form's code window...
Private Sub Form_Load()
Dim MyNumber As Double
' Set the value of MyNumber to a value, say 4
MyNumber = 4
' This next statement will generate the correct value
' of 16 (note that no parentheses are used).
SquareMe myNumber
MsgBox MyNumber)
' Reset the value of variable back to its original value
MyNumber = 4
' This next statement will generate the wrong value
' because it is surrounded in parentheses.
SquareMe (myNumber)
MsgBox MyNumber
End Sub
Sub SquareMe(ByRef X As Double)
X = X * X
End Sub
The SquareMe subroutine takes its passed value, multiplies it by itself and
then uses the fact that it was passed ByRef to send the updated value back
to the calling code by assigning the new value directly to the passed
argument. When no parentheses surround the argument, the variable is updated
correctly; but when the argument is surrounded by parentheses, the variable
does not get updated (the calculated variable was returned to the temporary
memory location where the "expression" was evaluated at before being passed
to the subroutine instead of the actual memory address of the variable
itself.
You will be doing yourself a big favor if you break the habit you have of
placing parentheses around arguments, now, before it becomes too ingrained a
habit to break later on.
Rick
