面板ArrangeOverride和MeasureOverride方法

Question

有人能为这个函数提供一个简单的例子吗？我想意识到的是这样的事情：

当我有一个孩子-我想要显示在全屏上；

当我有两个孩子-我想要有相同的高度和宽度，并被显示在一个完整的一行；

当我有3个孩子时，就像这样：

|*************|
|   1  |   2  |
|*************|
|      3      |
|*************|

当我有4个孩子的时候：

|*************|
|   1  |   2  |
|*************|
|   3  |   4  |
|*************|

我怎样才能做到这一点？

致以问候。

编辑1:我认为这个面板可以继承UniformGrid。

Answer 1

您似乎不需要覆盖MeasureOverride，因为您的面板将占用所有可用空间，因此您只需要在ArrangeOverride中实现您的放置逻辑，如下所示：

public class CustomPanel : Panel
{
    protected override Size ArrangeOverride(Size finalSize)
    {
        if (Children.Count == 1)
        {
            Children[0].Arrange(new Rect(new Point(0, 0), finalSize));
        }
        else if (Children.Count == 2)
        {
            var halfFinalSize = new Size(finalSize.Width, finalSize.Height/2);
            Children[0].Arrange(new Rect(new Point(0, 0), halfFinalSize));
            Children[1].Arrange(new Rect(new Point(0, finalSize.Height / 2), halfFinalSize));
        }
        else if (Children.Count == 3)
        {
            var halfFinalSize = new Size(finalSize.Width, finalSize.Height / 2);
            var quarterSize = new Size(finalSize.Width / 2, finalSize.Height / 2);

            Children[0].Arrange(new Rect(new Point(0, 0), halfFinalSize));
            Children[1].Arrange(new Rect(new Point(0, finalSize.Height / 2), quarterSize));
            Children[2].Arrange(new Rect(new Point(finalSize.Width / 2, finalSize.Height / 2), quarterSize));
        }
        else if (Children.Count == 4)
        {
            var quarterSize = new Size(finalSize.Width / 2, finalSize.Height / 2);
            Children[0].Arrange(new Rect(new Point(0, 0), quarterSize));
            Children[1].Arrange(new Rect(new Point(finalSize.Width / 2, 0), quarterSize));
            Children[2].Arrange(new Rect(new Point(0, finalSize.Height / 2), quarterSize));
            Children[3].Arrange(new Rect(new Point(finalSize.Width / 2, finalSize.Height / 2), quarterSize));
        }
        else if (Children.Count > 4)
        {
            //???
        }

        return base.ArrangeOverride(finalSize);
    }
}`

PS:确保孩子的数量少于5