【自定义控件】MyPanelParent MyParent

代码

MyPanelParent.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows;
using System.Windows.Controls;

namespace MyPanels
{
    public class MyPanelParent : Panel
    {
        /// <summary>
        /// 
        /// </summary>
        /// <param name="availableSize">1、UIElement Measure（）方法 根据元素的Clip、Visibility生成constraintSize，然后传递给 FrameworkElement 的MeasureCore（）方法  2、</param>
        /// <returns></returns>
        protected override  Size MeasureOverride(Size availableSize)
        {
            foreach (UIElement item in this.InternalChildren)
            {
                item.Measure(new Size(120, 120));//这里是入口
            }

            return availableSize;
        }

        protected override  Size ArrangeOverride(Size finalSize)
        {
            double x = 100;
            foreach (UIElement item in this.InternalChildren)
            {
                item.Arrange(new Rect(x, 0, item.DesiredSize.Width, item.DesiredSize.Height));
                x += item.DesiredSize.Width;
            }

            return finalSize;
        }
    }

}

MyPanel.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows;
using System.Windows.Controls;

namespace MyPanels
{
    public class MyPanel : Panel
    {
        protected override System.Windows.Size MeasureOverride(System.Windows.Size availableSize)
        {
            foreach (UIElement item in this.InternalChildren)
            {
                item.Measure(availableSize);
            }
            return new Size(50, 50);//MyPanel 返回它期望的大小
        }

        protected override System.Windows.Size ArrangeOverride(System.Windows.Size finalSize)
        {
            double xCordinate = 0;
            foreach (UIElement item in this.InternalChildren)
            {
                item.Arrange(new Rect(new Point(xCordinate, 0), item.DesiredSize));
                xCordinate += item.DesiredSize.Width;
            }
            return finalSize;
        }
    }
}

效果

具体过程分析