c# - 面板 ArrangeOverride 和 MeasureOverride 方法

Question

有人可以为这个功能提供一个简单的例子吗？我想要实现的是这样的:

当我有 1 个 child 时 - 我想全屏显示；

当我有 2 个 child 时 - 我希望具有相同的高度和宽度，并且每个 child 都显示在整行中；

当我有 3 个 child 时，是这样的:

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

当我有 4 个 child 时:

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

我怎样才能做到这一点？

问候。

编辑 1:我认为这个面板可以继承 UniformGrid somwhow。

Answer 1

似乎您不需要覆盖 MeasureOverride 因为您的面板将占用所有可用空间，所以您只需要在 ArrangeOverride 中实现您的放置逻辑，例如这个:

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 Children 计数小于 5