When to use variables, objects and CTYPE?   

Hello
Under what conditions "must" you use "CTYPE" when working with variables and 
objects?

date: Thu, 30 Aug 2007 19:56:02 -0700   author:   winlin

Re: When to use variables, objects and CTYPE?   

"winlin"  wrote in message 
news:20A3E762-5DC3-409E-ACBB-192BD3864046@microsoft.com...
> Hello
> Under what conditions "must" you use "CTYPE" when working with variables 
> and
> objects?

Can you provide some sort of contextual information on what you want to do 
that you believe needs ctype?
Normally, if I need to make a specific conversion that requires "forcing, I 
use explicit_cast<type>(argument).

date: Fri, 31 Aug 2007 18:55:12 -0500   author:   PvdG42

Re: When to use variables, objects and CTYPE?   

You must use CType when your code has the OPTION STRICT ON either in the 
project properties or in the VB Code itself and when the conversion is a 
narrowing one.

For instance, you can always write:  Dim i as Integer
                                                       Dim d as Double = i
But if you have set "Option strict On" in the project properties or in the 
code, Dim d as Double
                                                                             
                                        Dim i as Integer = d will not 
compile,
                                                                             
            you have to write:  Dim d as Double
                                                                             
                                         Dim i as Integer = CType(d, double) 
(it's a way to tell the compiler that you know what you are 
doing)
For objects, if Customer Inherits from Person, you can always write: Dim C 
as new Customer
                                                                             
                            Dim P as Person = C
But with Option Strict On, if you write Dim C as new Customer
                                                           Dim P as Person = 
C
                                                           Dim D as Customer 
= P, the compiler will not accept the last statement
it will accept: Dim C as new Customer
                     Dim P as Persomn = C
                     Dim D as Customer = CType(P, Customer)

I hope I am clear enough. Sometimes my students understand what I say.

Marc Biotteau, MCT

"winlin"  wrote in message 
news:20A3E762-5DC3-409E-ACBB-192BD3864046@microsoft.com...
> Hello
> Under what conditions "must" you use "CTYPE" when working with variables 
> and
> objects?

date: Tue, 27 Nov 2007 21:57:26 -0500   author:   Wannano