Question

I am designing a form in which I have to increase a Progress bar while an operation is being performed simultaneously (In other words, I am showing the progress of this operation).
This operation takes 50 seconds. So I have used a System.Timer to Increase the Progress bar.

There isn’t a single thread in my code. When I write Progress_bar.PerformStep() in Timer Event Handler, it gives error as “Cross Thread Operation Not Valid”.

[From this error I analyzed that System.Timer must be creating a Thread and Runs the timer in it to perform multiple tasks.]

What should I do to increase my progress bar after every Second?

I tried solution given in this question. It removed the error but Now I can’t see the progress bar increasing. Means it Starts…. No Increase for 50 sec and after it 100%.

Code is as follows:

Timer Declaration (It is Global):

public System.Timers.Timer Thetimer = new System.Timers.Timer(1000);

Event Declaration (This is in Constructor to make it…err…Public [May not be a correct word]):

Thetimer.Elapsed += new ElapsedEventHandler(_timer_Elapsed);

Call:

 Thetimer.Start();

 blRetVal = FunctionToBeExecuted(parameter);

 Thetimer.Stop();

Event Handler:

 void _timer_Elapsed(object sender, ElapsedEventArgs e)
        {
           //StatusBar.PerformStep();  -- Tried This. It gives the Error

/* This doesn't give an error but Another issue Arises */

            if (InvokeRequired)
            {
                BeginInvoke(new Action(StatusBar.PerformStep));

            }
            else
                StatusBar.PerformStep();
        }

P.S. I am using C# and Visual Studio 2008

Answer 1

It sounds like you’re performing your “background” operation on the main thread, which is why your progress bar doesn’t update when you invoke it.

Have a look at BackgroundWorker.