How to stop a loop created in another thread

Question

I made a image recorder in a loop below, but I don't understand how I can stop recording. Here's my code

void Capture()
{
    while (true)
    {
        Bitmap bm= new Bitmap(Screen.PrimaryScreen.Bounds.Width, Screen.PrimaryScreen.Bounds.Height);
        Graphics g = Graphics.FromImage(bm);
        g.CopyFromScreen(0, 0, 0, 0, bm.Size);
        pictureBox1.Image = bm;
        Thread.Sleep(300);
    }
}

private void btnRecord_Click(object sender, EventArgs e)
{
    Thread t = new Thread(Capture);
    t.Start();
}

Please help me!

How do i save the recording? – John Doe Aug 11 '18 at 20:43 — John Doe, Aug 11 '18 at 20:43

score 3 · Answer 1 · answered Aug 11 '18 at 20:28

3

Because of your loop you have a very simple ways: set a flag as a request to stop:

private volatile bool reqToStopRec = false;

void Capture()
{
    while (!reqToStopRec)
    {
        Bitmap bm= new Bitmap(Screen.PrimaryScreen.Bounds.Width, Screen.PrimaryScreen.Bounds.Height);
        Graphics g = Graphics.FromImage(bm);
        g.CopyFromScreen(0, 0, 0, 0, bm.Size);
        pictureBox1.Image = bm;
        Thread.Sleep(300);
    }
    reqToStopRec = false;
}

private void btnRecord_Click(object sender, EventArgs e)
{
    Thread t = new Thread(Capture);
    t.Start();
}

private void btnStop_Click(object sender, EventArgs e)
{
    reqToStopRec = true;
}

In C# bool writes and reads are atomic so all you need is volatile.

answered Aug 11 '18 at 20:28

bolov

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how do u save the recording – John Doe Aug 11 '18 at 20:58
@JohnDoe We have a policy on SO of one question per post. – bolov Aug 11 '18 at 21:12
oh um could u comment it? – John Doe Aug 11 '18 at 22:33

How to stop a loop created in another thread

1 Answers1