C#

private void DrawTextBoxBorder(Graphics g)
{
    Rectangle rectClient = myTextBox.ClientRectangle;
    Rectangle rect = myTextBox.RectangleToScreen(rectClient);
    rect.Offset(-1,-1);
    rect.Width += 1;
    rect.Height += 1;

    Point ptClient = new Point(0,0);
    Point ptScreen = PointToScreen(ptClient);
    rect.Offset(-ptScreen.X, -ptScreen.Y);

    g.DrawRectangle(Pens.SlateGray, rect);
}

public class TextBoxEx :TextBox
{
private Color borderColor;
public TextBoxEx()
{
	this.SetStyle(ControlStyles.UserPaint,true);
	this.BorderStyle=BorderStyle.FixedSingle;
	borderColor=Color.Red;

}
public Color BorderColor
{
	get
	{
		return borderColor;
	}
	set
	{
		borderColor=value;
	}
}
protected override void OnBorderStyleChanged(EventArgs e)
{
	this.BorderStyle=BorderStyle.FixedSingle;
	base.OnBorderStyleChanged (e);
}

protected override void OnPaint(PaintEventArgs e)
{
	base.OnPaint (e);
	ControlPaint.DrawBorder
		(e.Graphics,e.ClipRectangle,borderColor,ButtonBorderStyle.Solid);
	
}

Pen p=new Pen(new SolidBrush(this.BackColor));
g.DrawLine(p,x1,y1,x2,y2);

private static object sLock = new object();

private void Timer_elapsed(object source, EventArgs e)
{
   lock (sLock)
   {
      //Timer code here.
   }
}

private void FileWatcher_event(object source, EventArgs e)
{
   lock (sLock)
   {
      //File code here.
   }
}