Solved

pass objects

Posted on 2009-04-07
7
173 Views
Last Modified: 2013-12-17
I am passing a  list of objects.
I want to change  values in the list.
IS there any problem with this as it is a little  confusing. Am I changing a copy of the list or the actual list ?


obj1 - create list of objects
-----
 Dim missileList As New List(Of ClassMissile)
  Public Property GetMissiles() As List(Of ClassMissile)
        Get
            Return missileList
        End Get
   

    obj2 -get  list and change values
---------

   Dim missiles As List(Of ClassMissile)
        missiles = Sprite.GetMissiles
          For Each Mymissile In missiles
...
mymissile.y=0 'is this changing the list property as i think it should?
----------------------
0
Comment
Question by:jagguy
7 Comments
 
LVL 15

Expert Comment

by:oobayly
ID: 24086108
You should be changing the actual list, but the easiest way to test is this:
' Get the list

Dim missiles1 As List(Of ClassMissile) = Sprite.GetMissiles()
 

' Change an item

missiles1(0).y = 123456
 

' Get the list again

Dim missiles2 As List(Of ClassMissile) = Sprite.GetMissiles()
 

' Compare y for the 1st item

Dim b As Boolean = (missiles1(0).y = missiles2(0).y)

Open in new window

0
 
LVL 9

Expert Comment

by:Sreedhar Vengala
ID: 24086134
You are changing acutal list.
0
 

Author Comment

by:jagguy
ID: 24086166

When i pass the list am i passing the whole data around ?

IF I am passing the whole data around i could as well use a public list in a module.
0
Is Your Active Directory as Secure as You Think?

More than 75% of all records are compromised because of the loss or theft of a privileged credential. Experts have been exploring Active Directory infrastructure to identify key threats and establish best practices for keeping data safe. Attend this month’s webinar to learn more.

 
LVL 15

Expert Comment

by:oobayly
ID: 24086263
Well, technically you're returning a reference to the object data.
As for modules, I'd stay clear of them, and stick with Object Orientated code.
0
 
LVL 6

Expert Comment

by:HarryNS
ID: 24086407
If you need to work with the list that contains value without changing the list, use <your LIst>.CopyTo(Array). This will copy the values to new array. There you can change values and use.
0
 
LVL 85

Accepted Solution

by:
Mike Tomlinson earned 500 total points
ID: 24088558
"When i pass the list am i passing the whole data around?"

As oobayly stated you are only passing a reference.  Stated differently, you are NOT passing the entire List around...just the pointer to the List (but we don't deal with pointers in managed .Net so they are called "references").  Think of it as passing the key to the front door of a house.  It allows you access to the house without passing the entire house....
0
 
LVL 15

Expert Comment

by:oobayly
ID: 24088583
@Idle_Mind
I like that analogy.
0

Featured Post

Is Your Active Directory as Secure as You Think?

More than 75% of all records are compromised because of the loss or theft of a privileged credential. Experts have been exploring Active Directory infrastructure to identify key threats and establish best practices for keeping data safe. Attend this month’s webinar to learn more.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

This article describes relatively difficult and non-obvious issues that are likely to arise when creating COM class in Visual Studio and deploying it by professional MSI-authoring tools. It is assumed that the reader is already familiar with the cla…
Many of us here at EE write code. Many of us write exceptional code; just as many of us write exception-prone code. As we all should know, exceptions are a mechanism for handling errors which are typically out of our control. From database errors, t…
Delivering innovative fully-managed cloud services for mission-critical applications requires expertise in multiple areas plus vision and commitment. Meet a few of the people behind the quality services of Concerto.
The Email Laundry PDF encryption service allows companies to send confidential encrypted  emails to anybody. The PDF document can also contain attachments that are embedded in the encrypted PDF. The password is randomly generated by The Email Laundr…

937 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question

Need Help in Real-Time?

Connect with top rated Experts

10 Experts available now in Live!

Get 1:1 Help Now