?
Solved

pass objects

Posted on 2009-04-07
7
Medium Priority
?
178 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
[X]
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
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
Independent Software Vendors: We Want Your Opinion

We value your feedback.

Take our survey and automatically be enter to win anyone of the following:
Yeti Cooler, Amazon eGift Card, and Movie eGift Card!

 
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 86

Accepted Solution

by:
Mike Tomlinson earned 2000 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

Technology Partners: We Want Your Opinion!

We value your feedback.

Take our survey and automatically be enter to win anyone of the following:
Yeti Cooler, Amazon eGift Card, and Movie eGift Card!

Question has a verified solution.

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

The ECB site provides FX rates for major currencies since its inception in 1999 in the form of an XML feed. The files have the following format (reducted for brevity) (CODE) There are three files available HERE (http://www.ecb.europa.eu/stats/exch…
This article shows how to deploy dynamic backgrounds to computers depending on the aspect ratio of display
NetCrunch network monitor is a highly extensive platform for network monitoring and alert generation. In this video you'll see a live demo of NetCrunch with most notable features explained in a walk-through manner. You'll also get to know the philos…
Visualize your data even better in Access queries. Given a date and a value, this lesson shows how to compare that value with the previous value, calculate the difference, and display a circle if the value is the same, an up triangle if it increased…
Suggested Courses

764 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