progress bars with timer not working c#

hi

thanks for your reply is the timer not running in a seperate thread anyway?

sorry can you elaborate on what you mean please? do i have to create a specific thread for the timer?

many thanks,

Matt.

The timer is owned by UI thread.


//
public delegate void myMethodDelegate( int val );

public void update(int val){
   Progress_Bar.Value = val;
}


// on you thread you can call
this.Invoke(new myMethodDelegate( update, new object[]{24} ));

sorry can you explain this further please. Do you mean in the timer tick method?

thanks,

Matt.

hi i removed the timer and used

system.threading.

however because i am trying to update the progress of the bar in a seperate thread i get the following exception. any ideas on how i get around this?

i did read about the backgroundworker class. would you recommend using this over threading?

matt.

       private void tick(object sender, EventArgs e)
        {
            Progress_Bar.PerformStep();
        }
 
            System.Timers.Timer timer = new System.Timers.Timer(); 
            timer.Interval = 1000; 
            timer.Elapsed += new System.Timers.ElapsedEventHandler(tick); 
            timer.Start();
 
            Progress_Bar.Visible = true;
            Progress_Bar.Minimum = 0;
            Progress_Bar.Maximum = 24;
            Progress_Bar.Step = 1;
            Progress_Bar.Value = 0

                                              

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hi,

i've used a backgroundworker to run this however the same problem is happening with the hanging until the method has completed the time out. any ideas why? please find the code attached.

many thanks,

matt.

        private void backgroundWorker1_DoWork(object sender, DoWorkEventArgs e)
        {
                for (int i = 0; i < 24; i++)   
                {   
                    System.Threading.Thread.Sleep(1000); //do some intense task here.   
                    backgroundWorker1.ReportProgress(i*(100/24)); //notify progress to main thread. We also pass time information in UserState to cover this property in the example.   
 
                    //if cancellation is pending, cancel work.   
                    if (backgroundWorker1.CancellationPending)   
                    {   
                        e.Cancel = true;    
                        return;   
                    }   
                } 
        }
 
//i invoke as follows
 
            Progress_Bar.Visible = true;
            Progress_Bar.Minimum = 0;
            Progress_Bar.Maximum = 100;
            Progress_Bar.Value = 0;
            backgroundWorker1.RunWorkerAsync();

                                              

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sorry forgot to include this method too.

       private void backgroundWorker1_ProgressChanged(object sender, ProgressChangedEventArgs e)   
        {   
            Progress_Bar.Value = e.ProgressPercentage; //update progress bar   
        } 

                                              

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>>>> is the timer not running in a seperate thread anyway?
>>>> sorry can you elaborate on what you mean please? do i have to create a specific thread for the timer?

I have no experience with managed C++ or C# but perhaps I can put some light to the timers and the threading.

Your dialog runs in that what junges called the UI thread. Normally, it is the main and only thread. That UI thread permanently is running in a loop which looks like (pseudo code)

   while (PeekMessage(mainWnd, Message))
   {
         GetMessage(mainWnd, Message);
         TranslateMessage(mainWnd, Message);
         DispatchMessage(mainWnd, Message);
   }

In the DispatchMessage all handlers will be called that are provided by your classes  or by system classes . Those handlers will post (set at end) or send (set at front) new messages to this so-called message pump, what keeps the system running. The loop ends when a WM_QUIT message was processed and then the UI thread (and normally) the process could end as well.

Given that message loop, there are two ways in Windows how to implement a timer.

(1) Performing a timer in the UI thread by using the message loop

Here no further thread is involved but handled by the message queue itself. After a timer was installed a WM_TIMER message was fired when the time has expired. You handle the timer message in a handler function like OnTimer.

Note, the WM_TIMER is a low priority message. It only was retrieved (and dispatched) in message queue if not higher priority messages were to process.

Another note: when OnTimer was called you are in the main thread and in the message loop. Any waiting or blocking action would freeze the screen as no (more) messages were processed.

So, when using a message queue timer you could update the progress bar (and kill or renew the timer as appropriate) and return immediately but not have some lengthy code like performing a slow database query or even connect to another network device.

(2) Using a system timer in a thread

With that your main thread couldn't hang as the timer was in a new thread. You would invoke a new thread (worker thread) which sets a system timer. Then the thread would wait until the timeout. After awakening you would retrieve the progress state (somehow) and post a (private) message to the UI thread.  The UI thread has a handler for that private message and would set the progress-bar according to the progress information given with the message.

hi from what i can see does the backgroundworker class not work in its own thread then?

so you'd recommend i went down the system threading method? how can i then access the progress bar using this method?

thanks for all your help in advance!


Matt.

private void tick(object sender, EventArgs e)
        {
            Progress_Bar.PerformStep();
        }
 
            System.Timers.Timer timer = new System.Timers.Timer(); 
            timer.Interval = 1000; 
            timer.Elapsed += new System.Timers.ElapsedEventHandler(tick); 
            timer.Start();
 
            Progress_Bar.Visible = true;
            Progress_Bar.Minimum = 0;
            Progress_Bar.Maximum = 24;
            Progress_Bar.Step = 1;
            Progress_Bar.Value = 0
 
Open in New WindowSelect All

                                              

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Is it me, or are you looking for ProgressBar.Style = ProgressBarStyle.Marquee, without any kind of timer, or any other magic...

Windows Forms ProgressBar: Easiest way to start/stop marquee?
http://stackoverflow.com/questions/312936/windows-forms-progressbar-easiest-way-to-start-stop-marquee

Start:
  progressBar1.Style = ProgressBarStyle.Marquee;
  progressBar1.MarqueeAnimationSpeed = 30;

Stop:
  progressBar1.Style = ProgressBarStyle.Block;
  progressBar1.MarqueeAnimationSpeed = 0;

hi thats, perfect for my first screen!

however i have a second screen which includes a lengthy sql db creation, population, etc.

i have broken the sql statements down into chunks and store it in a static class.

now to monitor the progress of this i am going to use a public int in the static class containing the sql, so after each sql insert, etc i update the int as to the progress (i.e. add 1 to it after each query).

I then want the timer to poll this integer so it knows how far through the process we are and fill the progress bar accordingly.

so i will need a timer running in a seperate thread. Am i right in thinking that the Background worker is running in a seperate thread?

or should i go back to using the system.threading.thread?

many thanks for everyones help on this,

Matt.

"i have broken the sql statements down into chunks and store it in a static class."
What do you mean by "chunks"?

sorry by this i mean i execute each create, insert, seperately.

so for example id execute

CREATE table .....

then update the progress by 1

CREATE second table

update progress

etc....

that way i know how far the program has got through the db creation. so if i poll the global int at any point the returned value should tell me the its progress? do this sound viable?

many thanks for your reply.

Matt.

If you have a BackgroundWorker, and you know how much work needs to be done, then you can use the ReportProgress method, which raises the ProcessChanged event.

BackgroundWorker.ReportProgress Method
http://msdn.microsoft.com/en-us/library/ka89zff4.aspx

C# Copy Code 
// Abort the operation if the user has canceled.
// Note that a call to CancelAsync may have set 
// CancellationPending to true just after the
// last invocation of this method exits, so this 
// code will not have the opportunity to set the 
// DoWorkEventArgs.Cancel flag to true. This means
// that RunWorkerCompletedEventArgs.Cancelled will
// not be set to true in your RunWorkerCompleted
// event handler. This is a race condition.
 
if (worker.CancellationPending)
{   
    e.Cancel = true;
}
else
{   
    if (n < 2)
    {   
        result = 1;
    }
    else
    {   
        result = ComputeFibonacci(n - 1, worker, e) + 
                 ComputeFibonacci(n - 2, worker, e);
    }
 
    // Report progress as a percentage of the total task.
    int percentComplete = 
        (int)((float)n / (float)numberToCompute * 100);
    if (percentComplete > highestPercentageReached)
    {
        highestPercentageReached = percentComplete;
        worker.ReportProgress(percentComplete);
    }
}
                                              

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thanks sorry for the delay in the reply learnedone.

With this solution i am essentially passing the progress to the background worker.

however, i think in my case it is the other way around.

All of my sql, etc, is in contained in a static class.  

so to explain more, from my windows form i call the sql insertion method which will run setting a global max_progress int (which gives the overall progress to be reched) and a progress int, this is the current progress.

i've been trying to get the background work to poll this every second and this is where the problem is as it (even though i backgroundworker is working on a seperate thread, it doesn't seem to be polling until the sql has completed.)

Now i suppose i could alter the method to pass a reference to the background worker being used and update it tht way? would you recommend doing this, so i could then use report progress that way? the only problem here is that i could just then pass a ref to the progress bar and manually update that then, which kind of defeats the point of running on a seperate thread?

many thanks for all youre help in advance,

Matt.

 

Can you give me some kind of clue how you are using the BackgroundWorker?

>>>> even though i backgroundworker is working on a seperate thread, it doesn't seem to be polling until the sql has completed

Indeed. If you have a lengthy SQL statement to query your background thread would not be able to report progress until all results were received.

There are two ways out:

(1) Show the progress in a timer function of the main thread but show no procentual progress but only the elapsed time until the background thread was done.

(2) Change the select statement so that it receives the results in chunks. E. g. if your data has a contiguous number as an attribute, determine MIN and MAX of that attribute at the beginning and now have - say - 10 queries where the first one would have 'and NUMBER_ATTRIBUTE >= :x and NUMBER_ATTRIBUTE < :y' as an additional condition where x was the minimum number and y was minimum + (maximum-minimum/10);

hi thanks for both your comments, as requested heres how i do it

in the button click event is start the background worker as follows;


                backgroundWorker1.RunWorkerAsync();

i then run my static class db creation method.

                SqlClass.CreateDatabase(dbname);

       public static void createDatabase(String db)
        {
            //set max for reading completion status
            max_progress = 28;

            //create a connection
            SqlConnection conn = createConn();
            SqlDataReader reader = null;

            //with create do a select to check exists
            String sql = @" CREATE DATABASE " + db + ";"  +
                         @" SELECT * FROM sys.databases WHERE name = '" + db + "'";

            reader = executeSql(sql, ref conn);

            if(reader == null)
            {
                CustomMessage customMessage = new CustomMessage();
                throw new CustomException.CustomException(SeverityLevel.Fatal, GlobalVars.Debuglog, new Exception(), customMessage.GetString("Create_DB"));
            }

            reader.Close();
            reader = null;

            progress = 1;
           
            sql = @" Use " + db + ";";

            reader = executeSql(sql, ref conn);
            reader.Close();
            reader = null;

            progress = 2;

            sql = @"    CREATE TABLE ....

                        IF EXISTS (...
                        ) SELECT 1 AS res";

            reader = executeSql(sql, ref conn);
           
            if(reader == null)
            {
                CustomMessage customMessage = new CustomMessage();
                throw new CustomException.CustomException(SeverityLevel.Fatal, GlobalVars.Debuglog, new Exception(), customMessage.GetString("Create_centre"));
            }

            reader.Close();
            reader = null;

            progress = 3;

            sql = @"    CREATE TABLE [room]...
                   
                        IF EXISTS (...
                        ) SELECT 1 AS res";

            reader = executeSql(sql, ref conn);

            if(reader == null)
            {
                CustomMessage customMessage = new CustomMessage();
                throw new CustomException.CustomException(SeverityLevel.Fatal, GlobalVars.Debuglog, new Exception(), customMessage.GetString("Create_room"));
            }

            reader.Close();
            reader = null;

           etc... up to 28

and the background worker method is as follows;

        private void backgroundWorker1_DoWork(object sender, DoWorkEventArgs e)
        {
            //invoke this and keep looking up the progress and update to the progress bar
            System.Threading.Thread.Sleep(100);
            Progress_Bar.Value = (SqlLogin.Progress * (100/SqlLogin.MaxProgress));
        }

if you need anything else let me know.


many thanks for your time on this.

Matt.

So, you aren't using the ReportProgress event?

You do all the database creation in the button handler?

yes to both is this a problem?

do i need to use the reportprogress method?

yes i call the creation method in the static class from the button hanlder method. is there a better way of doing this?