Draw pixels by using the letters a-z

Question

I wanted to draw a pixel on a specific place in my form when I press a specific key in my keyboard. how can I do that? here's a snippet code from my project:

 private void paint(object sender, PaintEventArgs e)
    {

     int x = 5, y = 5;
     e.Graphics.FillRectangle(Brushes.Black, new Rectangle(55, 55, x, y));}

Handling the key press would be a first step (http://stackoverflow.com/questions/3001237/how-to-catch-a-key-press-on-a-c-sharp-net-form). See if you can then call your method from that and, if not, post the updated code — keyboardP, Jul 18 '16 at 18:12
this is the code i am working on: 'private void press(object sender, KeyEventArgs e, PaintEventArgs g) int x = 5, y = 5; if (e.KeyValue <'a' && e.KeyValue <= 'z'){ MessageBox.Show("Form.KeyPress: '" + e.KeyValue.ToString() + "' pressed."); switch (e.KeyValue) { case (char) 'a': g.Graphics.FillRectangle(Brushes.Black, new Rectangle(55, 55, x, y)); break; case (char)'b': case (char)'c': MessageBox.Show("Form.KeyPress: '" + e.KeyValue.ToString() + "' consumed."); e.Handled = true; break; } }' @keyboardP — M. rit, Jul 18 '16 at 18:18

score -1 · Accepted Answer · answered Jul 18 '16 at 18:23

-1

I'm a little rusty to winforms, but I think you should try this:

Select the main form, go to the properties window, go to the events part of the properties window, and click "KeyDown."

In the KeyDown method, put in this:

    if (e.KeyCode == Keys.A)
    {
        Graphics g = this.CreateGraphics();
        Pen pen = new Pen(Color.Black, 2);
        Brush brush = Brushes.Black;

        int x = 5;
        int y = 5;
        g.FillRectangle(brush, x, y, 55, 55);
    }

VOILA!

answered Jul 18 '16 at 18:23

Xephyr

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Bad advice to use `CreateGraphics()`. It's volatile. Painting should _always_ be done in a proper `Paint` event. – DonBoitnott Jul 18 '16 at 18:46
@DonBoitnott is right. Anything drawn with this method will be erased if the form is repainted or if a window crosses in front of it. Also, the `Graphics` instance you get from `CreateGraphics` may not be the same as the one you get in the `OnPaint` override. The on in `OnPaint` might different if the form is double buffered, for example. – Chris Dunaway Jul 18 '16 at 20:54

Draw pixels by using the letters a-z

1 Answers1