Layout相关

1. 获得一个控件相对于另一个控件的位置

//Vector vector = VisualTreeHelper.GetOffset(relativeControl);

//Canvas.SetLeft(this,vector.X);

//Canvas.SetTop(this, vector.Y);

//UIElement.TranslatePoint(new Point(0,0),parentWindow) //Translates a point relative to this element to coordinates that are relative to the specified element.

2. Canvas 的 ClipToBounds="True" 属性， 这个属性比较有用，默认为false,这样会让在canvas显示范围外面的children也能显示出来，这样不太好。

3.MeasureOverride（Size availableSize),  返回希望的size,主要在其中调用  element.Measure(new Size(Double.PositiveInfinity, Double.PositiveInfinity));获得disableSize. ArrangeOverride(Size finalSize) 第一次传入(0,0),第二次传入父节点给其的size.

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Windows.Controls;
using System.Windows;
using System.Windows.Markup;
using Pfs.Pam.GUI.Controls;

namespace OverLayDemo
{
    public class OverLayout : Canvas
    {

     
        protected override Size MeasureOverride(Size availableSize)
        {
            foreach (UIElement element in Children)
            {
                element.Measure(new Size(Double.PositiveInfinity, Double.PositiveInfinity));
            }

            if (availableSize.Equals(new Size(Double.PositiveInfinity, Double.PositiveInfinity)))
            {
                return base.MeasureOverride(availableSize);
            }
            return availableSize;
        }

        protected override Size ArrangeOverride(Size finalSize)
        {
            if (finalSize.Equals(new Size(0, 0)))
                return finalSize;
            Point leftTop = new Point(0, 0);
            Point leftBottom = new Point(0, finalSize.Height);
            Point leftMiddle = new Point(0, finalSize.Height / 2);
            Point middleTop = new Point(finalSize.Width / 2, 0);
            Point middleBottom = new Point(finalSize.Width / 2, finalSize.Height);
            Point rightTop = new Point(finalSize.Width, 0);
            Point rightMiddle = new Point(finalSize.Width, finalSize.Height / 2);
            Point rightBottom = new Point(finalSize.Width, finalSize.Height);

            foreach (UIElement element in Children)
            {
                OverLayPanel panel = element as OverLayPanel;
                if (panel == null) //|| panel .IsDrag == true
                    continue;

                if (panel.SlideOutMode == Location.Left)
                {
                    if (panel.VerticalPositionMode == VerticalAlignment.Top)
                        element.Arrange(new Rect(leftTop, element.DesiredSize));
                    else if (panel.VerticalPositionMode == VerticalAlignment.Middle)
                        element.Arrange(new Rect(new Point(0, leftMiddle.Y - element.DesiredSize.Height / 2), element.DesiredSize));
                    else if (panel.VerticalPositionMode == VerticalAlignment.Bottom)
                        element.Arrange(new Rect(new Point(0, leftBottom.Y - element.DesiredSize.Height), element.DesiredSize));
                    else
                        element.Arrange(new Rect(leftTop, finalSize));

                }
                else if (panel.SlideOutMode == Location.Rigth)
                {
                    if (panel.VerticalPositionMode == VerticalAlignment.Top)
                        element.Arrange(new Rect(new Point(rightTop.X - element.DesiredSize.Width, 0), element.DesiredSize));
                    else if (panel.VerticalPositionMode == VerticalAlignment.Middle)
                        element.Arrange(new Rect(new Point(rightMiddle.X - element.DesiredSize.Width, rightMiddle.Y - element.DesiredSize.Height / 2), element.DesiredSize));
                    else if (panel.VerticalPositionMode == VerticalAlignment.Bottom)
                        element.Arrange(new Rect(new Point(rightBottom.X - element.DesiredSize.Width, rightBottom.Y - element.DesiredSize.Height), element.DesiredSize));
                    else
                        element.Arrange(new Rect(leftTop, finalSize));
                }
                else if (panel.SlideOutMode == Location.Top)
                {
                    if (panel.HorizontalPositionMode == HorizontalAlignment.Left)
                        element.Arrange(new Rect(leftTop, element.DesiredSize));
                    else if (panel.HorizontalPositionMode == HorizontalAlignment.Center)
                        element.Arrange(new Rect(new Point(middleTop.X - element.DesiredSize.Width / 2, 0), element.DesiredSize));
                    else if (panel.HorizontalPositionMode == HorizontalAlignment.Right)
                        element.Arrange(new Rect(new Point(rightTop.X - element.DesiredSize.Width, 0), element.DesiredSize));
                    else
                        element.Arrange(new Rect(leftTop, finalSize));
                }
                else if (panel.SlideOutMode == Location.Bottom)
                {
                    if (panel.HorizontalPositionMode == HorizontalAlignment.Left)
                        element.Arrange(new Rect(new Point(0, leftBottom.Y - element.DesiredSize.Height), element.DesiredSize));
                    else if (panel.HorizontalPositionMode == HorizontalAlignment.Center)
                    {
                        element.Arrange(new Rect(new Point(middleBottom.X - element.DesiredSize.Width / 2, middleBottom.Y - element.DesiredSize.Height), element.DesiredSize));
                    }
                    else if (panel.HorizontalPositionMode == HorizontalAlignment.Right)
                        element.Arrange(new Rect(new Point(rightBottom.X - element.DesiredSize.Width, rightBottom.Y - element.DesiredSize.Height), element.DesiredSize));
                    else
                        element.Arrange(new Rect(leftTop, finalSize));
                }
            }

            return finalSize;
        }

    }
}

改ControlTemplate:

<ControlTemplate>

<Rectangle RadiusX="15" RadiusY="15" Margin="4,4,4,4"  SnapsToDevicePixels="True" Fill="LightBlue"/>

 <ContentPresenter x:Name="OverlayPanelContent" DockPanel.Dock="Top" />

</ControlTemplate>