WPF MeasureOverride和 ArrangeOverride做个 页面导航

 public class NavigationPanel:Panel
    {
        protected override Size MeasureOverride(Size availableSize)
        {
            Size size = new Size();
            for (int i = 0; i < this.InternalChildren.Count; i++)
            {
                var child = this.InternalChildren[i];
                child.Measure(availableSize);
                size = child.DesiredSize;
            }
            return base.MeasureOverride(size);
        }

        protected override Size ArrangeOverride(Size finalSize)
        {
            var thisWidth = finalSize.Width;
            for (int i = 0; i < this.InternalChildren.Count; i++)
            {
                var child = this.InternalChildren[i];
                var poingX = thisWidth - child.DesiredSize.Width;
                if (poingX > 0)
                {
                    child.Arrange(new Rect(new Point(poingX, 0), child.DesiredSize));
                }
                else
                {
                    child.Arrange(new Rect(new Point(0, 0), child.DesiredSize));
                }
            }
            return base.ArrangeOverride(finalSize);
        }
    }

<local:NavigationPanel x:Name="_navigationpanel_" Width="60" MaxWidth="300" Background="Yellow" HorizontalAlignment="Left">
            <Button BorderBrush="Black" Background="Red" Content="0" Width="40" Margin="10" Click="Button_Click"></Button>
        </local:NavigationPanel>

 private void Button_Click(object sender, RoutedEventArgs e)
        {
            if (_navigationpanel_.Width == 300) _navigationpanel_.Width = 60; else _navigationpanel_.Width = 300;
            
        }

当然这只是个半成品，还可以向NavigationPanel中加入子控件来做一个完整的导航。

用MeasureOverride和 ArrangeOverride做导航最大的好处是：

1、在控件的最上层

2、可以随着窗体大小来调整Height

导航实现方式有很多，这个纯粹是为了MeasureOverride和 ArrangeOverride 练手。