AStartTest.Form1.button1_Click C# (CSharp) Method

        private void button1_Click(object sender, EventArgs e)
        {
            tileMap.ClearPath();
            DateTime time1 = DateTime.Now;
            DateTime time2;
            if (aStar == null)
                aStar = new AStar(tileMap);

            aStar.Iterate(ref current, ref open, ref closed);

            current.SetTileType(TileType.Current);

            for (int i = 0; i < open.Count; i++)
            {
                if (open[i].TileType != TileType.Start &&
                    open[i].TileType != TileType.Goal)
                    open[i].SetTileType(TileType.Open);
            }

            for (int i = 0; i < closed.Count; i++)
            {
                if (closed[i].TileType != TileType.Start &&
                    closed[i].TileType != TileType.Goal)
                    closed[i].SetTileType(TileType.Closed);
            }
            time2 = DateTime.Now;
            timelbl.Text = "Time: " + time2.Subtract(time1).ToString();
        }