299 lines
10 KiB
C#
299 lines
10 KiB
C#
using System.Windows.Markup;
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namespace Melskin.Layout;
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/// <summary>
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/// StackPanel 类继承自 Panel，用于在用户界面中以垂直或水平方式排列子元素。它支持设置子元素之间的间距、方向以及单个子项的填充方式。
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/// </summary>
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[ContentProperty(nameof(Children))]
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public class StackPanel : Panel
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{
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/// <summary>
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/// 设置某子项附加属性，控制其是否填充到当前StackPanel所在的面板（控制单个子项的在面板填充方式）
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/// </summary>
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public static readonly DependencyProperty FillProperty = DependencyProperty.RegisterAttached(
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"Fill",
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typeof(FillType),
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typeof(StackPanel),
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new FrameworkPropertyMetadata(
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FillType.Auto,
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FrameworkPropertyMetadataOptions.AffectsArrange |
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FrameworkPropertyMetadataOptions.AffectsMeasure |
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FrameworkPropertyMetadataOptions.AffectsParentArrange |
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FrameworkPropertyMetadataOptions.AffectsParentMeasure));
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/// <summary>
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/// 定义 StackPanel 的排列方向，可以设置为水平或垂直。此属性影响子元素的布局方式。
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/// </summary>
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public static readonly DependencyProperty OrientationProperty = DependencyProperty.Register(
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nameof(Orientation),
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typeof(Orientation),
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typeof(StackPanel),
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new FrameworkPropertyMetadata(
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Orientation.Vertical,
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FrameworkPropertyMetadataOptions.AffectsArrange | FrameworkPropertyMetadataOptions.AffectsMeasure));
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/// <summary>
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/// 定义子元素之间的间距。此属性允许用户指定StackPanel中相邻子元素间的距离。
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/// </summary>
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public static readonly DependencyProperty SpacingProperty = DependencyProperty.Register(
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nameof(Spacing),
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typeof(double),
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typeof(StackPanel),
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new FrameworkPropertyMetadata(
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0.0,
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FrameworkPropertyMetadataOptions.AffectsArrange | FrameworkPropertyMetadataOptions.AffectsMeasure));
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static double CalculateTotalMarginToAdd(UIElementCollection children, double marginBetweenChildren)
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{
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//可见的子项数量
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var visibleChildrenCount = children
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.OfType<UIElement>()
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.Count(x => x.Visibility != Visibility.Collapsed && GetFill(x) != FillType.Ignored);
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var marginMultiplier = Math.Max(visibleChildrenCount - 1, 0);
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var totalMarginToAdd = marginBetweenChildren * marginMultiplier;
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return totalMarginToAdd;
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}
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/// <inheritdoc />
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protected override Size ArrangeOverride(Size arrangeSize)
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{
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var children = InternalChildren;
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var totalChildrenCount = children.Count;
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double accumulatedLeft = 0;
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double accumulatedTop = 0;
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var isHorizontal = Orientation == Orientation.Horizontal;
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var spacing = Spacing;
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var totalMarginToAdd = CalculateTotalMarginToAdd(children, spacing);
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var allAutoSizedSum = 0.0;
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var countOfFillTypes = 0;
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foreach (var child in children.OfType<UIElement>())
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{
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var fillType = GetFill(child);
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if (fillType != FillType.Auto)
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{
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if (child.Visibility != Visibility.Collapsed && fillType != FillType.Ignored)
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countOfFillTypes += 1;
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}
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else
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{
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var desiredSize = isHorizontal ? child.DesiredSize.Width : child.DesiredSize.Height;
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allAutoSizedSum += desiredSize;
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}
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}
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var remainingForFillTypes = isHorizontal
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? Math.Max(0, arrangeSize.Width - allAutoSizedSum - totalMarginToAdd)
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: Math.Max(0, arrangeSize.Height - allAutoSizedSum - totalMarginToAdd);
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var fillTypeSize = remainingForFillTypes / countOfFillTypes;
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for (var i = 0; i < totalChildrenCount; ++i)
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{
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var child = children[i];
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if (child == null)
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{
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continue;
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}
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var childDesiredSize = child.DesiredSize;
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var fillType = GetFill(child);
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var isCollapsed = child.Visibility == Visibility.Collapsed || fillType == FillType.Ignored;
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var isLastChild = i == totalChildrenCount - 1;
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var marginToAdd = isLastChild || isCollapsed ? 0 : spacing;
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var rcChild = new Rect(
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accumulatedLeft,
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accumulatedTop,
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Math.Max(0.0, arrangeSize.Width - accumulatedLeft),
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Math.Max(0.0, arrangeSize.Height - accumulatedTop));
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if (isHorizontal)
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{
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rcChild.Width = fillType == FillType.Auto || isCollapsed ? childDesiredSize.Width : fillTypeSize;
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rcChild.Height = arrangeSize.Height;
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accumulatedLeft += rcChild.Width + marginToAdd;
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}
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else
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{
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rcChild.Width = arrangeSize.Width;
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rcChild.Height = fillType == FillType.Auto || isCollapsed ? childDesiredSize.Height : fillTypeSize;
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accumulatedTop += rcChild.Height + marginToAdd;
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}
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child.Arrange(rcChild);
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}
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return arrangeSize;
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}
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/// <inheritdoc />
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protected override Size MeasureOverride(Size constraint)
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{
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var children = InternalChildren;
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double parentWidth = 0;
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double parentHeight = 0;
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double accumulatedWidth = 0;
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double accumulatedHeight = 0;
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var isHorizontal = Orientation == Orientation.Horizontal;
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var totalMarginToAdd = CalculateTotalMarginToAdd(children, Spacing);
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for (var i = 0; i < children.Count; i++)
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{
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var child = children[i];
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if (child == null)
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{
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continue;
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}
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// 先处理Auto的情况，再计算Fill的剩余空间
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if (GetFill(child) != FillType.Auto)
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{
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continue;
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}
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// 子项约束为剩余大小; 即总大小减去前一个子项目消耗的大小。
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var childConstraint = new Size(
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Math.Max(0.0, constraint.Width - accumulatedWidth),
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Math.Max(0.0, constraint.Height - accumulatedHeight));
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// 计算子项
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child.Measure(childConstraint);
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var childDesiredSize = child.DesiredSize;
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if (isHorizontal)
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{
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accumulatedWidth += childDesiredSize.Width;
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parentHeight = Math.Max(parentHeight, accumulatedHeight + childDesiredSize.Height);
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}
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else
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{
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parentWidth = Math.Max(parentWidth, accumulatedWidth + childDesiredSize.Width);
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accumulatedHeight += childDesiredSize.Height;
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}
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}
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// 在计算剩余空间之前，将所有边距添加到累积大小中，以便填充元素。
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if (isHorizontal)
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{
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accumulatedWidth += totalMarginToAdd;
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}
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else
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{
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accumulatedHeight += totalMarginToAdd;
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}
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//Fill类型的总数量
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var totalCountOfFillTypes = children
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.OfType<UIElement>()
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.Count(x => GetFill(x) == FillType.Fill && x.Visibility != Visibility.Collapsed);
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//可用的剩余空间
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var availableSpaceRemaining = isHorizontal
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? Math.Max(0, constraint.Width - accumulatedWidth)
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: Math.Max(0, constraint.Height - accumulatedHeight);
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var eachFillTypeSize = totalCountOfFillTypes > 0 ? availableSpaceRemaining / totalCountOfFillTypes : 0;
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for (var i = 0; i < children.Count; i++)
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{
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var child = children[i];
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if (child == null)
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{
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continue;
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}
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// 处理所有的填充，给它们一部分剩余空间
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if (GetFill(child) != FillType.Fill)
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{
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continue;
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}
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// 子项限制是剩余大小；即总大小减去前一个子项限制所消耗的大小。
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var childConstraint = isHorizontal
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? new Size(eachFillTypeSize, Math.Max(0.0, constraint.Height - accumulatedHeight))
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: new Size(Math.Max(0.0, constraint.Width - accumulatedWidth), eachFillTypeSize);
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// 测量子项.
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child.Measure(childConstraint);
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var childDesiredSize = child.DesiredSize;
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if (isHorizontal)
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{
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accumulatedWidth += childDesiredSize.Width;
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parentHeight = Math.Max(parentHeight, accumulatedHeight + childDesiredSize.Height);
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}
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else
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{
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parentWidth = Math.Max(parentWidth, accumulatedWidth + childDesiredSize.Width);
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accumulatedHeight += childDesiredSize.Height;
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}
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}
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// 确保最终累积的大小反映在 parentSize 中。
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parentWidth = Math.Max(parentWidth, accumulatedWidth);
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parentHeight = Math.Max(parentHeight, accumulatedHeight);
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var parent = new Size(parentWidth, parentHeight);
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return parent;
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}
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/// <summary>
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/// 获取指定元素的填充类型。
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/// </summary>
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/// <param name="element">要获取填充类型的依赖对象。</param>
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/// <returns>返回指定元素的填充类型。</returns>
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public static FillType GetFill(DependencyObject element)
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{
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return (FillType)element.GetValue(FillProperty); }
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/// <summary>
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/// 设置指定元素的填充方式属性。
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/// </summary>
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/// <param name="element">要设置填充方式的依赖对象。</param>
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/// <param name="value">要设置的填充类型值，可以是Auto、Fill或Ignored。</param>
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public static void SetFill(DependencyObject element, FillType value)
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{
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element.SetValue(FillProperty, value); }
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/// <summary>
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/// 堆叠方向
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/// </summary>
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public Orientation Orientation
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{
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get => (Orientation)GetValue(OrientationProperty);
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set => SetValue(OrientationProperty, value);
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}
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/// <summary>
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/// 子项间距
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/// </summary>
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public double Spacing
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{
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get => (double)GetValue(SpacingProperty);
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set => SetValue(SpacingProperty, value);
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}
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}
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/// <summary>
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///
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/// </summary>
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public enum FillType
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{
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/// <summary>
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/// 实际大小填充
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/// </summary>
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Auto,
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/// <summary>
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/// 填充剩余空间相当于Stretch
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/// </summary>
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Fill,
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/// <summary>
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/// 忽略当前项
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/// </summary>
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Ignored
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}
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