对WPF中MeasureOverride 和ArrangeOverride 浅理解

以前对MeasureOverride 和ArrangeOverride十分费解，看到了这篇博文茅塞顿开~

 1 public class CustomControl1 : Panel

 2     {

 3         /// <summary>

 4         /// 先测量需要多大尺寸，做个申报准备

 5         /// </summary>

 6         /// <param name="constraint">限定的尺寸，比如，规定了width和height</param>

 7         /// <returns></returns>

 8         protected override Size MeasureOverride(Size constraint)

 9         {

10             //定义预期的宽度和高度

11             double height = 0, width = 0;

12             UIElement element;

13             //遍历每个元素，计算所需的总尺寸

14             for (int i = 0; i < Children.Count; i++)

15             {

16                 element = Children[i];

17                 //按照限定的尺寸测量一下自己，拿镜子找着自己

18                 element.Measure(constraint);

19                 if (height < element.DesiredSize.Height)

20                     height = element.DesiredSize.Height;

21                 width += element.DesiredSize.Width;

22             }

23             //申报，我需要这个尺寸

24             return new Size(width, height);

25         }

26        

27         /// <summary>

28         /// 排列每个元素

29         /// </summary>

30         /// <param name="arrangeBounds">测量的尺寸</param>

31         /// <returns></returns>

32         protected override Size ArrangeOverride(Size arrangeBounds)

33         {

34             double currentX = 100;

35             UIElement element;

36             for (int i = 0; i < Children.Count; i++)

37             {

38                 element = Children[i];

39                 //排列每个元素

40                 Children[i].Arrange(new Rect(currentX, 0, element.DesiredSize.Width, element.DesiredSize.Height));

41                 currentX += element.DesiredSize.Width;

42             }

43             return arrangeBounds;

44         }

45     }

1 <local:CustomControl1  Width="300" Background="Gray" HorizontalAlignment="Right" Margin="0,20,151,280">

2             <Rectangle Width="100" Height="50" Fill="Red" Margin="10,10,0,0" />

3             <Rectangle Width="100" Height="50" Fill="Yellow" Margin="10,10,0,0" />

4             <Rectangle Width="100" Height="50" Fill="Green" Margin="10,10,0,0" />

5         </local:CustomControl1>

本文来自xiaokang088的博客，原文地址:http://www.cnblogs.com/xiaokang088/archive/2011/01/08/1930952.html