// Feel free to use this code in any way you see fit
// www.warmforestflash.com

package com.warmforestflash.drawing
{
	import flash.display.Shape;
	import flash.display.BitmapData;
	import flash.geom.Rectangle;

	public class DottedLine extends Shape
	{
		private var _w:Number;
		private var _h:Number;
		private var _color:uint;
		private var _dotAlpha:Number;
		private var _dotWidth:Number;
		private var _spacing:Number;
		
		//============================================================================================================================
		public function DottedLine(w:Number = 100, h:Number = 1, color:uint = 0x777777, dotAlpha = 1, dotWidth:Number = 1, spacing:Number = 1)
		//============================================================================================================================
		{
			_w = w;
			_h = h;
			_color = color;
			this.alpha = dotAlpha;
			_dotWidth = dotWidth;
			_spacing = spacing;
			drawDottedLine();
		}
		
		//============================================================================================================================
		private function drawDottedLine():void
		//============================================================================================================================
		{
			graphics.clear();
			var tile:BitmapData = new BitmapData(_dotWidth + _spacing, _h + 1, true);
			var r1:Rectangle = new Rectangle(0, 0, _dotWidth, _h);
			var argb:uint = returnARGB(_color, 255);
			tile.fillRect(r1, argb);
			var r2:Rectangle = new Rectangle(_dotWidth, 0, _dotWidth + _spacing, _h);
			tile.fillRect(r2, 0x00000000);
			graphics.beginBitmapFill(tile, null, true);
			graphics.drawRect(0, 0, _w, _h);
			graphics.endFill();
		}
		
		//============================================================================================================================
		private function returnARGB(rgb:uint, newAlpha:uint):uint
		//============================================================================================================================
		{
			var argb:uint = 0;
			argb += (newAlpha<<24);
			argb += (rgb);
			return argb;
		}
		
	}
}

Draw Dotted lInes in Flash ( FOUND )

ActionScript 3