how to call onPaint from Timer

bimbambumbum

Hi I'm trying to work my way into the world of .NET programming so this question might be a no-brainer. I'm trying to make a timer-control redrawing GDI graphics so that the GUI gets updated at regular time intervals. The overrided OnPaint() is currently doing the drawing and it should be called from the timer_tick() method. Please take a look at the code below. I looked for an onPaint() redraw/update method but couldn't find such one. Can someone please give me a hint? Thanks Tom

public partial class Form1 : Form
{
Timer timer = new Timer();
Graphics g;
int x2 = 100; // the end location of the line being drawn
int y2 = 100; // the end location of the line being drawn

    public Form1()
    {
        InitializeComponent();

        timer.Tick += new EventHandler(timer\_tick);
        timer.Interval = 1000;      // update graphics every sec!!
        timer.Enabled = true;
        timer.Start();

    }

    void timer\_tick(object sender, EventArgs e)
    {
        //MessageBox.Show("Tick");                    // Alert the user       
    }

    private void Form1\_Paint(object sender, PaintEventArgs e)
    {
    }

    protected override void OnPaint(PaintEventArgs pe)
    {
        g = pe.Graphics;

        // Draw coordinate system
        Pen pn = new Pen(Color.Black, 1);
        Point pt1 = new Point(0, 0);
        Point pt2 = new Point(x2, y2++);
        g.DrawLine(pn, pt1, pt2);

        if (y2 > 300)
            y2 = 100;       // increment y-coordinate to see that onPaint gets called from timer

    }

Abhinav S

Does this.Refresh(); help?

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bimbambumbum

It sure does... Thanks this is great Tom :)

Thomas Stockwell

this.invalidate() works as well

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