C# Forms, drawing a progress line

Question

I have the following code:

public async void startCountdown()
{
    do
    {               
        label9.Text = frsL.ToString();

        frsL -= frsLStep;

        g = tabPage1.CreateGraphics();
        g.DrawLine(pen1, 5, 7, (int)frsL + 5, 7);

        await Task.Delay(1000);

    } while (timeToSeconds());
}

I'm trying to refresh a progress line every second, but the line isn't changing. I used label9 just to check if frsL value is changing and it is, but the line isn't redrawn and it stays at it's starting length.

Answer 1

Yeah, the problem was that the line is decreasing and I have to remove the old line before drawing the new one. Inserting 'g.Clear(Color.White);' before 'g.DrawLine' fixed the problem. The bad thing is that sometimes the whole line flashes.

Answer 2

Hi I suggest you to put a timer in your form , set it's interval on 1000 and paste your code in it's tick function.

good luck!