Re: Threading Question - C# Discussion Boards

Nader Elshehabi12-Dec-06 7:40

12-Dec-06 7:40

As long as your threads are objects inside your class, they can manipulate any field -even private ones- including strings. My suggestion to your situation is to make a string obkect inside your class. then either you:
1- Make a single common method that takes parameters passed by the calling thread to add it to the single string object
2- Access that single string object in the different methods of threads -you don't need to return- the way that suits you -this is if you got different methods for different threads. If they all start with the same method, this won't apply-.
Very important thing to note is to apply a lock on the string object to prevent threads from modifying it simultaneously.

Regards

NameYou12-Dec-06 8:25

12-Dec-06 8:25

Let me give you some psudeo code - because I'm not understanding. Here is what I am doing:

public class MainClass
{

private void GetData()
{

MyObject mo = new MyObject();
Thread t = new Thread(new ThreadStart(mo.Connect));
t.Start();

MyObject mo2 = new MyObject();
Thread t2 = new Thread(new ThreadStart(mo2.Connect));
t2.Start();

MyObject mo2 = new MyObject();
Thread t3 = new Thread(new ThreadStart(mo3.Connect));
t3.Start();

MyObject mo3 = new MyObject();
Thread t4 = new Thread(new ThreadStart(mo4.Connect));
t4.Start();

//WHAT I WANT TO DO IS BE ABLE TO GRAB THE RESULTS FROM THE THREADS STARTED ABOVE
//AND PUSH THEM INTO A FILE. I NEED ALL OF THE DATA FROM ALL FOUR THREADS COMBINED INTO ONE FILE
}

}

Public class MyObject
{
public MyObject()
{
}

public void Connect()
{
//Starts all the socket stuff..
}

//...OTHER SOCKET RELATED FUNCTIONS GO HERE.
}

How do I get the data in the Connect function to the calling function in MainClass?

uh... yeah

Nader Elshehabi12-Dec-06 8:54

12-Dec-06 8:54

NameYou wrote:
How do I get the data in the Connect function to the calling function in MainClass?

You don't need to. If there is no good reason not to access the file from that method, you should.
To be specific, here is my suggestion of you MyObject.Connect() method:

Public class MyObject
{
    public MyObject()
    {
    }

    public void Connect()
    {
        //Starts all the socket stuff..
        object LockObject = new object()
        lock(LockObject)
        {
            StreamWriter MyStream = File.AppendText("MyFile.txt");
            MyStream.WriteLine(Input);
            MyStream.Close();
        }
    }
    //...OTHER SOCKET RELATED FUNCTIONS GO HERE.
}

Of course you got to do some modifications to the code to suite your needs, but I hope this was close enough.

Regards

NameYou12-Dec-06 9:47

12-Dec-06 9:47

Ah I see what you are saying - my problem is this: then I have multiple disk IO reads, which will slow the system down compared to one. In this project, speed is absolutely necessary. Is there any way that I can write it to memory, so that I can combine the 4 results and write to the file once?

C#... king of languages

Nader Elshehabi12-Dec-06 17:11

12-Dec-06 17:11

NameYou wrote:
Is there any way that I can write it to memory

Sure! You can make a string object in Connect method, keep concatenating strings to it, then finally at the end of your data reading write the whole string to the file. It's almost the same way.
PS.
EricDV is right. You should first make the LockObject private static for the lock to work. Another way to do it is to use Mutex class instead.

Regards

NameYou13-Dec-06 2:18

13-Dec-06 2:18

OK, I understand that, but what I am getting at is that if I had the data write to a file at the end of the reading routine, that file write routine would be executed 4 times (since I have four threads) which is slower than dumping all of the read data into a buffer and then writing the buffer outside of the 4 threads - am I correct? Speed is of the essence with this procedure.

C#, king of languages

Nader Elshehabi13-Dec-06 6:16

Re: Threading Question [modified]

13-Dec-06 6:16

Again this won't hurt. It would be a matter of milliseconds. Yet, if this small time really makes a difference with you, try benchmarking your program. For example, I do it by comparing the value of DateTime.Now.Ticks before and after the procedure I'm testing. See which method would give you the most satisfying results.

PS.
If you really need speed this much, why don't you think of unmanaged code -e.g. C++-?

Regards

Eric Dahlvang12-Dec-06 10:03

Eric Dahlvang

12-Dec-06 10:03

I'm no threading expert, but I think you need to consider that NameYou is creating multiple instances of MyObject. When you create LockObject in each instance, that means that each instances Connect code has a lock -- which is different from locking that piece of code for EVERY instance. You can see the difference by comparing the following two classes:

1)This just locks the code in this instances connect method.

public class MyObject
{
    public static string cFieldVal;

    public MyObject()
    {
    }

    public void Connect()
    {
        //Starts all the socket stuff..
        object LockObject = new object();
        lock(LockObject)
        {
            MessageBox.Show(MyObject.cFieldVal);
            MyObject.cFieldVal=MyObject.cFieldVal+="x";
            //StreamWriter MyStream = File.AppendText("MyFile.txt");
            //MyStream.WriteLine(Input);
           // MyStream.Close();
        }
    }
    //...OTHER SOCKET RELATED FUNCTIONS GO HERE.
}

2)This code locks a static field, so it is locked for ~~EACH~~ EVERY instance.

public class MyObject
{

    public static string cFieldVal="";

    public MyObject()
    {
    }

    public void Connect()
    {
        //Starts all the socket stuff..

        lock(cFieldVal)
        {
            MessageBox.Show(MyObject.cFieldVal);
            MyObject.cFieldVal=MyObject.cFieldVal+="x";
          //  StreamWriter MyStream = File.AppendText("MyFile.txt");
          //  MyStream.WriteLine(Input);
          //  MyStream.Close();
        }
    }
//...OTHER SOCKET RELATED FUNCTIONS GO HERE.
}

-- modified at 8:57 Wednesday 13th December, 2006

--EricDV Sig---------
Some problems are so complex that you have to be highly intelligent and well informed just to be undecided about them.
- Laurence J. Peters

Andy Brummer12-Dec-06 17:21

Andy Brummer

12-Dec-06 17:21

Actually, the first block doesn't do any locking at all since each method doesn't share the lock object.

Your example blocks all instances, it doesn't matter how many MyObjects there are, only one of them can execute the locked code at any time.

Removing the static keyword from cFieldVal will protect the value for each instance.

I can imagine the sinking feeling one would have after ordering my book,
only to find a laughably ridiculous theory with demented logic once the book arrives - Mark McCutcheon

Eric Dahlvang13-Dec-06 3:02

Eric Dahlvang

13-Dec-06 3:02

Andy Brummer wrote:
Actually, the first block doesn't do any locking at all since each method doesn't share the lock object.

That's what i was trying to say.

Andy Brummer wrote:
Your example blocks all instances, it doesn't matter how many MyObjects there are, only one of them can execute the locked code at any time.

Removing the static keyword from cFieldVal will protect the value for each instance.

The intention of the example was to have a lock that every instance shares, and I should have said EVERY rather than EACH. I have changed it. Thanks for pointing that out.

--EricDV Sig---------
Some problems are so complex that you have to be highly intelligent and well informed just to be undecided about them.
- Laurence J. Peters

Nader Elshehabi12-Dec-06 17:24

12-Dec-06 17:24

You are right. I've tested it. I hope I don't miss that next time. Smile | :)

Regards

karam chandrabose12-Dec-06 22:45

karam chandrabose

12-Dec-06 22:45

I would suggest you to use asynchronous method invocation and callbacks to make this task much much simpler

NameYou13-Dec-06 1:32

13-Dec-06 1:32

I'm not sure I understand Asynchronous method calling? I've never seen that before. Could you point me in the direction of some information on that, or shoot me over some example code?

uh... yeah

sno-114-Dec-06 3:52

sno-1

14-Dec-06 3:52

first sorry if I give'nt you a good answer because I dont undertand you a lot, ok this is fact:

if you need know the process data of this 4 thread, you can use many tools, such as delegate, create a delegate and add all this function inside this, and then put the delegate on execution, for more explanation look this example, using a ProgressBar...

public delegate void ExceutionAsyncronous();
public void function1(){}
public void function2(){}
public void function3(){}

public void RequestTime(ProgressBar som, int value, int max)
{
som.Increment(value++,max);
}

inside your function put this method "RequestTime" in a way that the increment always keeping inside a correct interval, an then ...

ExceutionAsyncronous ob = new ExceutionAsyncronous(function1);
ob+=new ExceutionAsyncronous(function2);
ob+=new ExceutionAsyncronous(function3);
ob();

Remember that this explanation only want give you a Idea, ok

if you need know anything else, please write me ok
Big Grin | :-D

font

hadad12-Dec-06 6:49

hadad

12-Dec-06 6:49

my app language is arabic but the pc that I will deploy this app on it does not support the arabic language . I want my app to solve this problem from whithin it.at the setup project.

Dad

Re: font

Nader Elshehabi12-Dec-06 7:59

sending messages to a window from a windows service

12-Dec-06 7:59

What you are talking about is called localization. In brief; Localization is determining the culture -i.e. the interface language,\among other things of course- of your program at runtime, allowing your program to support multiple languages based on the choice of the user.
If you want to know more about localization click here[^].

Regards

George_Lucian12-Dec-06 5:49

George_Lucian

12-Dec-06 5:49

...i have the following problem: i have a windows service that when it starts opens the serial port COM1 and then listens on it. Once it receives something(a code) it does something to winamp(depending on the code received e.g. 1=play,2=stop...etc.).to see if it works i have connected pin2 with pin3 of the serial port and i have added a timer in the service which from second to second sends a code to the serial. when i install the service and start it it does nothing to the winamp...i have debugged the code and found out that the function associated to winamp function is executed with no errors (
IntPtr hwnd = SerialPortListner.PortListener.FindWindow(windowName, null);
SerialPortListner.PortListener.SendMessageA(hwnd, WM_COMMAND, WA_STOP, WA_NOTHING);) when the timer event is raised...but i do not know why it does nothing to winamp(play,stop...etc). If i put the exact same code in a windows application it works perfect but in the service it does nothing...
...can u help me pls... thx in advance!

Re: sending messages to a window from a windows service

Nader Elshehabi12-Dec-06 8:05