Question

I have a problem about using multithreading in c#. I have a complex computing thing that must run on the main thread means it must run on the main window.

My program runs like this :

• First it will open a new window and user can input parameter
• Then it will run a complex computing that must run in the main thread ( i can’t change this, i’m using library that prevent call the computing thing in different thread, if i’m using different thread it will come with an exception).
• When the simulation run, it will also open a new window that monitoring the computing, it will also plot the graphic for it, and i need it to be real time.

Problem: Since the long time complex computing is running on the main thread, the monitoring window will be hang and not responding. Is there any tricky way to solve this? Can i use different thread to run the monitoring window? the main form is okay for not responding, but not okay for monitoring window. Here i put some code that resembles my program, not my real program, but the flow is the same.

Main Form(main thread that will run the computing thing,and input parameter from user)

public partial class Form1 : Form
{
    public Form1()
    {
        InitializeComponent();
    }

    private void button1_Click(object sender, EventArgs e)
    {
        compute c = new compute();
        c.computing();
    }
}

Graph Form (Monitoring Graph that will plot chart, needed to be real time)

    public graphic()
    {
        InitializeComponent();
    }

    private void label1_Click(object sender, EventArgs e)
    {

    }

    public void updateLabel(int count)
    {
        label1.Text = "Current i value:  " + count;
    }

Compute class (doing the computing thing)

class compute
{
    delegate void writeToForm(int i);
    graphic g = new graphic();

    public compute()
    {
        g.Show();
    }
    public void computing()
    {
       //THIS PART MUST RUN ON THE MAIN THREAD, DON'T MAKE IT ON THE OTHER THREAD
       //IT IS A MUST
        int count = 0;
        //THIS IS THE LONG TIME COMPUTING THING
        for (int i = 0; i < 100; i++)
        {
            count += i;
            updateLabel(count);
            Thread.Sleep(2000);
        }
    }

    private void updateLabel(int count)
    {
        if (g.InvokeRequired)
        {
            g.Invoke(new writeToForm(updateLabel), new object[] { count });
            return;
        }
        g.updateLabel(count);
    }
}

I can’t do anything about the method must run in the main thread, i’m using library that prevent its method to be ran from other method, thanks..

Answer 1

A possible workaround would be to write your monitoring form in another program, which can be launched by your main program before the computing method is executed. Yes, your main form will still hang (but you say this isn’t a problem?).

You could communicate with your main application, possibly by opening a local TCP connection (which can run on a different thread without a problem). This could send commands to the monitoring application (or any other connected TCP clients if you wish), which would receive these and use the Control.Invoke method to update the UI.