473,806 Members | 2,878 Online
Bytes | Software Development & Data Engineering Community
+ Post

Home Posts Topics Members FAQ

FYI: Using ArrayList.Synch ronized on Derived Classes

I've seen a few messages on this, but no responses. Here's what I
found out

PROBLEM:
How do you use ArrayList.Synch ronized to create thread-safe objects
derived from ArrayList

public class MyList : ArrayList
{
}

// This throws an exception
MyList list = (MyList)ArrayLi st.Synchronized (new MyList)
ANSWER:
You can't. ArrayList.Synch ronized returns a new ArrayList object.
Sorry.

THE (not so great) SOLUTION:
Instead of deriving from ArrayList, Wrap it.

public class MyList : IList
{
private ArrayList inner;
public MyList()
{
inner = ArrayList.Synch ronized(new ArrayList);
}

// Implement the IList members using the inner ArrayList
public object this[int index]
{
get
{
return inner[index];
}
set
{
inner[index] = value;
}
}

You get the rest...
If there is a better solution, post it!
Nov 15 '05 #1
0 1166

This thread has been closed and replies have been disabled. Please start a new discussion.

Similar topics

0
4566
by: John Lucas | last post by:
I have been reading many of the posts about determining which network card to use (in a machine with multiple nics), and determining whether or not that card is active. I'm hoping this will help others who are struggling with the same issues. This info exists in the groups, but not all in the same place. Thanks to everyone who contributes. Well done! Consider the following code:
1
1643
by: Iulian Ionescu | last post by:
I have the following problem. I derived a class from ArrayList to provide some additional events I need. Then I derived 2 different classes from this one and each of them defines an indexer that returns the specified object. For example, the list for Group types will have: public new Group this { get {return (Group)base;}
10
3597
by: Eric | last post by:
I'm looking at this page in the MSDN right here: ms-help://MS.MSDNQTR.2003FEB.1033/cpref/html/frlrfsystemcollectionsarraylist classsynchronizedtopic2.htm (or online here: http://msdn.microsoft.com/library/default.asp?url=/library/en-us/cpref/html/frlrfsystemcollectionsicollectionclasssyncroottopic.asp) And I'm interested in locking an ArrayList during the entire enumeration, as shown in the example code. My problem is that I'm STILL...
3
661
by: Igor | last post by:
Hi. I have ArrayList shared by many threads, I synchronized it with mutex. Now I discovered in MSDN that ArrayList should be synchronized with lock() and SyncRoot. Is it a problem that I synchronized it with mutex and what is the difference? Thanks.
2
1747
by: j3ko | last post by:
Hi, I'm trying to start a thread that constantly iterates through an arraylist of items that the main thread adds and removes from...how would I accomplish this? Here's the gist of what I have: (can anybody give me pointers on what i'm doing wrong?) Class SecondThread aList as new arraylist innerthread as new thread(addressof task)
1
8384
by: KK | last post by:
Dear All I have a class whose methods are getting called from multiple threads in my application. For example class DataDistribution { private ArrayList datset; public DataDistribution() { this.datset = new ArrayList();
3
2983
by: Ryan Liu | last post by:
Hi, What does ArrayList.Synchronized really do for an ArrayList? Is that equal to add lock(this) for all its public methods and properties? Not just for Add()/Insert()/Remvoe()/Count, but also for Item (this)? Normally,do I need sync at all? Isn't that true without sync the program can run faster?
10
8514
by: chrisben | last post by:
Hi, Here is the scenario. I have a list of IDs and there are multiple threads trying to add/remove/read from this list. I can do in C# 1. create Hashtable hList = Hashtable.Synchronized(new Hashtable()); 2. create ArrayList aList = ArrayList.Synchronized(new ArrayList()); 3. create a string sList = ""; For 1 and 2, since the list is synced, many threads can directly
28
1886
by: wanwan | last post by:
I wrote a class and have objects from this class added to an arraylist. When I retrieve the objects from the arraylist, should I use ctype or directcast to cast them back to the original class.?
0
9719
marktang
by: marktang | last post by:
ONU (Optical Network Unit) is one of the key components for providing high-speed Internet services. Its primary function is to act as an endpoint device located at the user's premises. However, people are often confused as to whether an ONU can Work As a Router. In this blog post, we’ll explore What is ONU, What Is Router, ONU & Router’s main usage, and What is the difference between ONU and Router. Let’s take a closer look ! Part I. Meaning of...
0
9597
by: Hystou | last post by:
Most computers default to English, but sometimes we require a different language, especially when relocating. Forgot to request a specific language before your computer shipped? No problem! You can effortlessly switch the default language on Windows 10 without reinstalling. I'll walk you through it. First, let's disable language synchronization. With a Microsoft account, language settings sync across devices. To prevent any complications,...
0
10618
Oralloy
by: Oralloy | last post by:
Hello folks, I am unable to find appropriate documentation on the type promotion of bit-fields when using the generalised comparison operator "<=>". The problem is that using the GNU compilers, it seems that the internal comparison operator "<=>" tries to promote arguments from unsigned to signed. This is as boiled down as I can make it. Here is my compilation command: g++-12 -std=c++20 -Wnarrowing bit_field.cpp Here is the code in...
1
10371
by: Hystou | last post by:
Overview: Windows 11 and 10 have less user interface control over operating system update behaviour than previous versions of Windows. In Windows 11 and 10, there is no way to turn off the Windows Update option using the Control Panel or Settings app; it automatically checks for updates and installs any it finds, whether you like it or not. For most users, this new feature is actually very convenient. If you want to control the update process,...
0
9187
agi2029
by: agi2029 | last post by:
Let's talk about the concept of autonomous AI software engineers and no-code agents. These AIs are designed to manage the entire lifecycle of a software development project—planning, coding, testing, and deployment—without human intervention. Imagine an AI that can take a project description, break it down, write the code, debug it, and then launch it, all on its own.... Now, this would greatly impact the work of software developers. The idea...
0
6877
by: conductexam | last post by:
I have .net C# application in which I am extracting data from word file and save it in database particularly. To store word all data as it is I am converting the whole word file firstly in HTML and then checking html paragraph one by one. At the time of converting from word file to html my equations which are in the word document file was convert into image. Globals.ThisAddIn.Application.ActiveDocument.Select();...
0
5678
by: adsilva | last post by:
A Windows Forms form does not have the event Unload, like VB6. What one acts like?
1
4329
by: 6302768590 | last post by:
Hai team i want code for transfer the data from one system to another through IP address by using C# our system has to for every 5mins then we have to update the data what the data is updated we have to send another system
2
3850
muto222
by: muto222 | last post by:
How can i add a mobile payment intergratation into php mysql website.

By using Bytes.com and it's services, you agree to our Privacy Policy and Terms of Use.

To disable or enable advertisements and analytics tracking please visit the manage ads & tracking page.