public class WrapPanel : Panel
    {
        public Orientation Orientation
        {
            get { return (Orientation)GetValue(OrientationProperty); }
            set { SetValue(OrientationProperty, value); }
        }

        public static readonly DependencyProperty OrientationProperty =
            DependencyProperty.Register("Orientation", typeof(Orientation), typeof(WrapPanel), null);

        public WrapPanel()
        {
            // default orientation
            Orientation = Orientation.Horizontal;
        }

        protected override Size MeasureOverride(Size availableSize)
        {

            Point point = new Point(0, 0);

            int i = 0;

            if (Orientation == Orientation.Horizontal)
            {
                double largestSubHeight = 0.0;
                double finalHeight = 0.0;

                foreach (UIElement child in Children)
                {
                    child.Measure(new Size(availableSize.Width, availableSize.Height));

                    if (child.DesiredSize.Height > largestSubHeight)
                        largestSubHeight = child.DesiredSize.Height;

                    point.X = point.X + child.DesiredSize.Width;

                    if ((i + 1) < Children.Count)
                    {
                        if ((point.X + Children[i + 1].DesiredSize.Width) > availableSize.Width)
                        {
                            point.X = 0;
                            point.Y = point.Y + largestSubHeight;
                            finalHeight += largestSubHeight;
                            largestSubHeight = 0.0;
                        }
                    }

                    i++;
                }

                return new Size(ActualWidth, finalHeight);
            }
            else
            {
                double largestSubWidth = 0.0;
                double finalWidth = 0.0;

                foreach (UIElement child in Children)
                {
                    child.Measure(new Size(availableSize.Width, availableSize.Height));

                    if (child.DesiredSize.Width > largestSubWidth)
                    {
                        largestSubWidth = child.DesiredSize.Width;
                    }

                    point.Y = point.Y + child.DesiredSize.Height;

                    if ((i + 1) < Children.Count)
                    {
                        if ((point.Y + Children[i + 1].DesiredSize.Height) > availableSize.Height)
                        {
                            point.Y = 0;
                            point.X = point.X + largestSubWidth;
                            finalWidth += largestSubWidth;
                            largestSubWidth = 0.0;
                        }
                    }

                    i++;
                }

                return new Size(finalWidth, ActualHeight);

            }
        }

        protected override Size ArrangeOverride(Size finalSize)
        {
            Point point = new Point(0, 0);

            int i = 0;

            if (Orientation == Orientation.Horizontal)
            {
                double largestSubHeight = 0.0;
                double finalHeight = 0.0;

                foreach (UIElement child in Children)
                {
                    child.Arrange(new Rect(point, new Point(point.X + child.DesiredSize.Width, point.Y + child.DesiredSize.Height)));

                    if (child.DesiredSize.Height > largestSubHeight)
                        largestSubHeight = child.DesiredSize.Height;

                    point.X = point.X + child.DesiredSize.Width;

                    if ((i + 1) < Children.Count)
                    {
                        if ((point.X + Children[i + 1].DesiredSize.Width) > finalSize.Width)
                        {
                            point.X = 0;
                            point.Y = point.Y + largestSubHeight;
                            finalHeight += largestSubHeight; 
                            largestSubHeight = 0.0;
                        }
                    }

                    i++;
                }

                return Size.Empty;
            }
            else
            {
                double largestSubWidth = 0.0;
                double finalWidth = 0.0;

                foreach (UIElement child in Children)
                {
                    child.Arrange(new Rect(point, new Point(point.X + child.DesiredSize.Width, point.Y + child.DesiredSize.Height)));

                    if (child.DesiredSize.Width > largestSubWidth)
                    {
                        largestSubWidth = child.DesiredSize.Width;
                    }

                    point.Y = point.Y + child.DesiredSize.Height;

                    if ((i + 1) < Children.Count)
                    {
                        if ((point.Y + Children[i + 1].DesiredSize.Height) > finalSize.Height)
                        {
                            point.Y = 0;
                            point.X = point.X + largestSubWidth;
                            finalWidth += largestSubWidth;
                            largestSubWidth = 0.0;
                        }
                    }

                    i++;
                }

            }

            return base.ArrangeOverride(finalSize);
        }
    }