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And then what happens when 2 users execute this code simultaneously?
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One of them will get an error message because they try to create a record with the same key.
---
b { font-weight: normal; }
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Correct, next question for 10 points 
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Set the id field to be a counter/identifier/auto_increment (depending on the flavour of database you are using). Then you just add a record without specifying the id at all, and it automatically gets a new unique id, without any risks of conflicts.
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b { font-weight: normal; }
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Please help my coding
How can I modify my loop to get a random number in the ArrayList which has values from 1 to 1000?
I use 5 threads running concurrently to get 2 random nuumbers from ArrayList, remove those 2 numbers, add together, and put the result back to ArrayList.
Thanks so much everyone.
using System;<br />
using System.Collections;<br />
using System.Text;<br />
using System.Threading;<br />
<br />
namespace A1_SS<br />
{<br />
class Program<br />
{<br />
static object lockObject;<br />
static ArrayList space;<br />
<br />
static void Main()<br />
{<br />
<br />
space = new ArrayList();<br />
<br />
for (int i = 1; i <= 10; i++)<br />
{<br />
space.Add(i);<br />
<br />
}<br />
<br />
lockObject = new object();<br />
<br />
<br />
Thread t1 = new Thread(new ParameterizedThreadStart(Program.AccessData));<br />
t1.Start(space);<br />
<br />
Thread t2 = new Thread(new ParameterizedThreadStart(Program.AccessData));<br />
t2.Start(space);<br />
<br />
Thread t3 = new Thread(new ParameterizedThreadStart(Program.AccessData));<br />
t3.Start(space);<br />
<br />
Thread t4 = new Thread(new ParameterizedThreadStart(Program.AccessData));<br />
t4.Start(space);<br />
<br />
Thread t5 = new Thread(new ParameterizedThreadStart(Program.AccessData));<br />
t5.Start(space);<br />
<br />
<br />
Thread.Sleep(20 * 1000);<br />
}<br />
<br />
<br />
<br />
public static void AccessData(object param)<br />
{<br />
<br />
ArrayList list = (ArrayList)param;<br />
<br />
lock (list)<br />
{<br />
<br />
Random rand = new Random();<br />
<br />
for (int i = 0; i <= list.Count; i++)<br />
{<br />
<br />
int x = rand.Next(list[i], list[list.]);<br />
list.Remove(x);<br />
Console.WriteLine("x = " + x);<br />
<br />
int y = rand.Next(1, list.Count);<br />
list.Remove(y);<br />
Console.WriteLine("y = " + y);<br />
<br />
int newNumber = x + y;<br />
Console.WriteLine("newNumber = " + newNumber);<br />
<br />
list.Add(newNumber);<br />
<br />
}<br />
<br />
foreach (object obj in list)<br />
Console.WriteLine(obj);<br />
<br />
<br />
}<br />
<br />
<br />
<br />
}<br />
}<br />
}
Eric
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Please dont post the same question 2 hours later.
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Sorry. I won't
I really need help
Thanks
eric
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Please help me how to create a random number in the ArrayList which has values from 1 to 1000.
Thanks
eric
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There is a Random class Random[^]
hope this helps...
Coulda, woulda, shoulda doesn't matter if you don't.
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How do you determine if a value of a comboxbox was changed by being clicked on? I have set databinding on the combobox and the values in it change when i scroll a datagrid.
Please help 
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I want authentication user to pass LDAP
can some body help me !!!1
thanks
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Please don't cross post.
Please write a descriptive subject.
---
b { font-weight: normal; }
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AnhTin wrote: I want authentication user to pass LDAP
In what scenario?
In what version of the .NET Framework
What type of application?
This might help, but since you don't give enough information it might not help: http://msdn.microsoft.com/library/default.asp?url=/library/en-us/dnnetsec/html/SecNetHT02.asp[^]
"On two occasions, I have been asked [by members of Parliament], 'Pray, Mr. Babbage, if you put into the machine wrong figures, will the right answers come out?' I am not able to rightly apprehend the kind of confusion of ideas that could provoke such a question."
--Charles Babbage (1791-1871)
My: Website | Blog
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Can anyone tell me how do I count the number of seconds elapsed after a certain piece of C# code is executed?
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I would create something to hold a start time. And then when I need to know the number of elapsed seconds I'd get the current time and calculate the difference.
"On two occasions, I have been asked [by members of Parliament], 'Pray, Mr. Babbage, if you put into the machine wrong figures, will the right answers come out?' I am not able to rightly apprehend the kind of confusion of ideas that could provoke such a question."
--Charles Babbage (1791-1871)
My: Website | Blog
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What do i need to write to get the start time and stop time?
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what do i need to write to get the start time and stop time?
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DateTime - DateTime = TimeSpan 
<br />
DateTime start = DateTime.Now;<br />
DoSomething();<br />
TimeSpan result = DateTime.Now - start;<br />
Console.WriteLine(result.Seconds);<br />
_________________________________
Please inform me about my English mistakes, as I'm still trying to learn your language!
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You can also use the Timer class. Set it to one second and count the number of times the ElapsedTimeEvent is called. I think however the DateTime methid would be better.
Coulda, woulda, shoulda doesn't matter if you don't.
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Hi all,
I want to create a video player in C# .net that should play all types of video files(.avi,MPEG).
Please give me some examples or articles on video player.
Thanks in advance
cheers
sangeet
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Actually I was trying to convert the Smack API tool that is written in Java using IKVMC to C#.net dll file. In the process of converting, it produced some errors saying that some of the classes or namespaces are missing. Can anyone provide an exact C# dll for smack API that is used with Jivesoftware for xmpp Instant messaging software.
sur
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Please show your ability!
I'd like to use 5 threads running concurrently. They use the same method AccessData to add 2 random numbers in the ArrayList of 1000 elements.
Is there anything wrong in my coding?
How to update the ArrayList after each thread?
How to terminate if there is only 1 number left in the ArrayList?
Thanks so much
using System;<br />
using System.Collections;<br />
using System.Text;<br />
using System.Threading;<br />
<br />
namespace A1_SS<br />
{<br />
class Program<br />
{<br />
static object lockObject;<br />
static ArrayList space;<br />
<br />
static void Main()<br />
{<br />
<br />
space = new ArrayList();<br />
<br />
for (int i = 1; i <= 1000; i++)<br />
{<br />
space.Add(i);<br />
<br />
}<br />
<br />
lockObject = new object();<br />
<br />
<br />
Thread t1 = new Thread(new ParameterizedThreadStart(Program.AccessData));<br />
t1.Start(space);<br />
<br />
Thread t2 = new Thread(new ParameterizedThreadStart(Program.AccessData));<br />
t2.Start(space);<br />
<br />
Thread t3 = new Thread(new ParameterizedThreadStart(Program.AccessData));<br />
t3.Start(space);<br />
<br />
Thread t4 = new Thread(new ParameterizedThreadStart(Program.AccessData));<br />
t4.Start(space);<br />
<br />
Thread t5 = new Thread(new ParameterizedThreadStart(Program.AccessData));<br />
t5.Start(space);<br />
}<br />
<br />
Thread.Sleep(20 * 1000);<br />
}<br />
<br />
<br />
<br />
public static void AccessData(object param)<br />
{ <br />
<br />
ArrayList list = (ArrayList)param;<br />
<br />
lock (lockObject)<br />
{<br />
<br />
<br />
Random rand = new Random();<br />
<br />
int x = rand.Next(1, list.Count);<br />
list.Remove(x);<br />
Console.WriteLine("x = " + x);<br />
<br />
int y = rand.Next(1, list.Count);<br />
list.Remove(y);<br />
Console.WriteLine("y = " + y);<br />
<br />
int newNumber = x + y;<br />
Console.WriteLine("newNumber = " + newNumber);<br />
<br />
list.Add(newNumber);<br />
<br />
<br />
<br />
foreach (object obj in list)<br />
Console.WriteLine(obj);<br />
<br />
<br />
}<br />
<br />
<br />
<br />
}<br />
}<br />
}<br />
eric
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Lots of problems in here.
1. Why are you using lock(lockObject), when lockObject is not being modified or even used by any thread at all!!! If you want to allow one thread at a time to modify your Array List, you should use lock(list).
2. In the code:
int x = rand.Next(1, list.Count);
list.Remove(x);
You are assuming that x is always present in the list. Whereas it is a possibility that x might have been removed by any other thread. Instead of removing the actual entry, you should use the indexes by using RemoveAt, and the number should not be x, it should be list[x].
3. The code written in the function will only execute five times, once per thread. So the list of 1000 will not get exhausted with this. You should use a loop to iterate through the list.
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Thanks so much
But what I mean for x is that I store a random number in ArrayList to x variable, and take that number out of the ArrayList.
Please help
eric
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Ok
I got it. I try now
Thanks Tehnoon
eric
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