Question

I’m trying to draw out pictureboxes during runtime as I can do right from the toolbox. That is, set the location at the mouselocation, resize it as I hold down the button and drag it across the form. All that I’ve accomplished in the code. But as I start the draw the second picturebox the first one disappears, I want to keep adding more pictureboxes to the form, if I remove the MouseMove event and move PictureBox pb1 = new PictureBox(); down to the MouseDown event it lets me add more buttons, but then I can’t resize them obviously.

    int cellSize = 10;
    int numOfCells = 500;

    PictureBox pb1 = new PictureBox();
    int Mx, My;

    public Form1()
    {
        InitializeComponent();
        this.DoubleBuffered = true;
    }

    public void pictureBox1_MouseMove(object sender, MouseEventArgs e)
    {
        Point p = new Point(e.X, e.Y);
        Mx = p.X;
        My = p.Y;
        int xSnap = (Mx / cellSize) * cellSize;
        int ySnap = (My / cellSize) * cellSize;

        pb1.BackColor = (Color.Red);

        if (e.Button == MouseButtons.Left)
        {
            pb1.Size = new Size(xSnap - pb1.Left, ySnap - pb1.Top);
        }
    }

    private void pictureBox1_MouseDown(object sender, MouseEventArgs e)
    {
        Point p = new Point(e.X, e.Y);
        Mx = p.X;
        My = p.Y;
        int xSnap = (Mx / cellSize) * cellSize;
        int ySnap = (My / cellSize) * cellSize;

        pb1.Location = new Point(xSnap, ySnap);
        pictureBox1.Controls.Add(pb1);
    }

Answer 1

You’re always re-using the same PictureBox instance.

You need to create a new instance every time you want to add a new one, by writing new PictureBox().