Classe PaintEventArgs

private Rectangle RcDraw;
		privatefloat PenWidth = 5;

		privatevoid Form1_MouseDown(object sender, System.Windows.Forms.MouseEventArgs e)
		{

			// Determine the initial rectangle coordinates...

			RcDraw.X = e.X;
			RcDraw.Y = e.Y;
		
		}

		privatevoid Form1_MouseUp(object sender, System.Windows.Forms.MouseEventArgs e)
		{

			// Determine the width and height of the rectangle...if(e.X < RcDraw.X)
			{
				RcDraw.Width = RcDraw.X - e.X;
				RcDraw.X = e.X;
			}
			else
			{
				RcDraw.Width = e.X - RcDraw.X;
			}

			if(e.Y < RcDraw.Y)
			{
				RcDraw.Height = RcDraw.Y - e.Y;
				RcDraw.Y = e.Y;
			}
			else
			{
				RcDraw.Height = e.Y - RcDraw.Y;
			}

			// Force a repaint of the region occupied by the rectangle...this.Invalidate(RcDraw);
		
		}

		privatevoid Form1_Paint(object sender, System.Windows.Forms.PaintEventArgs e)
		{

			// Draw the rectangle...

			e.Graphics.DrawRectangle(new Pen(Color.Blue, PenWidth), RcDraw);
			
		}

private Rectangle rcDraw;

private float penWidth = 5;

private void Form1_MouseDown(Object sender,
    System.Windows.Forms.MouseEventArgs e)
{
    // Determine the initial rectangle coordinates...
    rcDraw.set_X(e.get_X());
    rcDraw.set_Y(e.get_Y());
} //Form1_MouseDown

private void Form1_MouseUp(Object sender, 
    System.Windows.Forms.MouseEventArgs e)
{
    // Determine the width and height of the rectangle...
    if (e.get_X() < rcDraw.get_X()) {
        rcDraw.set_Width(rcDraw.get_X() - e.get_X());
        rcDraw.set_X(e.get_X());
    }
    else {
        rcDraw.set_Width(e.get_X() - rcDraw.get_X());
    }

    if (e.get_Y() < rcDraw.get_Y()) {
        rcDraw.set_Height(rcDraw.get_Y() - e.get_Y());
        rcDraw.set_Y(e.get_Y());
    }
    else {
        rcDraw.set_Height(e.get_Y() - rcDraw.get_Y());
    }

    // Force a repaint of the region occupied by the rectangle...
    this.Invalidate(rcDraw);
} //Form1_MouseUp

private void Form1_Paint(Object sender,
    System.Windows.Forms.PaintEventArgs e)
{
    // Draw the rectangle...
    e.get_Graphics().DrawRectangle(new Pen(Color.get_Blue(), 
        penWidth), rcDraw);
} //Form1_Paint

// This example creates a PictureBox control on the form and draws to it.// This example assumes that the Form_Load event handler method is// connected to the Load event of the form.private PictureBox pictureBox1 = new PictureBox();
privatevoid Form1_Load(object sender, System.EventArgs e)
{
    // Dock the PictureBox to the form and set its background to white.
    pictureBox1.Dock = DockStyle.Fill;
    pictureBox1.BackColor = Color.White;
    // Connect the Paint event of the PictureBox to the event handler method.
    pictureBox1.Paint += new System.Windows.Forms.PaintEventHandler(this.pictureBox1_Paint);

    // Add the PictureBox control to the Form.this.Controls.Add(pictureBox1);
}

privatevoid pictureBox1_Paint(object sender, System.Windows.Forms.PaintEventArgs e)
{
    // Create a local version of the graphics object for the PictureBox.
    Graphics g = e.Graphics;

    // Draw a string on the PictureBox.
    g.DrawString("This is a diagonal line drawn on the control",
        new Font("Arial",10), System.Drawing.Brushes.Blue, new Point(30,30));
    // Draw a line in the PictureBox.
    g.DrawLine(System.Drawing.Pens.Red, pictureBox1.Left, pictureBox1.Top,
        pictureBox1.Right, pictureBox1.Bottom);
}

// This example creates a PictureBox control on the form and draws to it.
// This example assumes that the Form_Load event handler method is
// connected to the Load event of the form.
private PictureBox pictureBox1 = new PictureBox();

private void Form1_Load(Object sender, System.EventArgs e)
{
    // Dock the PictureBox to the form and set its background to white.
    pictureBox1.set_Dock(DockStyle.Fill);
    pictureBox1.set_BackColor(Color.get_White());

    // Connect the Paint event of the PictureBox to the event handler 
    // method.
    pictureBox1.add_Paint(new System.Windows.Forms.PaintEventHandler(this.
        pictureBox1_Paint));

    // Add the PictureBox control to the Form.
    this.get_Controls().Add(pictureBox1);
} //Form1_Load

private void pictureBox1_Paint(Object sender, 
    System.Windows.Forms.PaintEventArgs e)
{
    // Create a local version of the graphics object for the PictureBox.
    Graphics g = e.get_Graphics();

    // Draw a string on the PictureBox.
    g.DrawString("This is a diagonal line drawn on the control", 
        new Font("Arial", 10), System.Drawing.Brushes.get_Blue(), 
        (PointF)new PointF(30, 30));

    // Draw a line in the PictureBox.
    g.DrawLine(System.Drawing.Pens.get_Red(), pictureBox1.get_Left(), 
        pictureBox1.get_Top(), pictureBox1.get_Right(), 
        pictureBox1.get_Bottom());
} //pictureBox1_Paint