306 lines
13 KiB
C#
306 lines
13 KiB
C#
namespace Melskin.Layout
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{
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/// <summary>
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/// 定义 FlexibleRowPanel 子元素的默认布局行为。
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/// </summary>
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public enum FlexibleRowLayoutMode
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{
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/// <summary>
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/// (默认) 子元素默认按比例分配空间 (等效于 Span = 1)。
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/// </summary>
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Proportional,
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/// <summary>
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/// 子元素默认根据其内容自动调整大小 (等效于 Span = -1)。
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/// </summary>
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Auto
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}
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/// <summary>
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/// 一个全能的单行布局面板，完美支持等分、权重、自动填充以及控件间距。
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/// </summary>
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public class FlexibleRowPanel : Panel
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{
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#region 1. 控件间距属性 (Spacing) - 【新增】
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/// <summary>
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/// 获取或设置子控件之间的间距。
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/// </summary>
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public static readonly DependencyProperty SpacingProperty =
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DependencyProperty.Register(nameof(Spacing), typeof(double), typeof(FlexibleRowPanel),
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new FrameworkPropertyMetadata(0.0, FrameworkPropertyMetadataOptions.AffectsMeasure));
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/// <summary>
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/// 获取或设置子控件之间的间距。
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/// 该属性定义了 FlexibleRowPanel 中相邻子控件间的距离。通过调整此值，可以控制布局中各元素的紧凑程度。
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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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#endregion
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#region 2. 面板模式属性 (LayoutMode)
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/// <summary>
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/// 获取或设置 FlexibleRowPanel 的布局模式，决定子控件的排列方式。
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/// </summary>
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public static readonly DependencyProperty LayoutModeProperty =
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DependencyProperty.Register(nameof(LayoutMode), typeof(FlexibleRowLayoutMode), typeof(FlexibleRowPanel),
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new FrameworkPropertyMetadata(FlexibleRowLayoutMode.Proportional, FrameworkPropertyMetadataOptions.AffectsMeasure));
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/// <summary>
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/// 获取或设置布局模式，决定子控件在面板中的排列方式。
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/// </summary>
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public FlexibleRowLayoutMode LayoutMode
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{
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get => (FlexibleRowLayoutMode)GetValue(LayoutModeProperty);
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set => SetValue(LayoutModeProperty, value);
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}
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#endregion
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#region 3. 便捷填充属性 (IsFill)
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/// <summary>
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/// 获取或设置是否允许控件在FlexibleRowPanel中自动填充剩余空间。
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/// </summary>
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public static readonly DependencyProperty IsFillProperty =
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DependencyProperty.RegisterAttached("IsFill", typeof(bool), typeof(FlexibleRowPanel),
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new FrameworkPropertyMetadata(false, OnIsFillChanged));
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/// <summary>
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/// 设置指定控件是否在FlexibleRowPanel中自动填充剩余空间。
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/// </summary>
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/// <param name="element">要设置属性的UI元素。</param>
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/// <param name="value">布尔值，指示是否允许该控件自动填充剩余空间。</param>
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public static void SetIsFill(UIElement element, bool value) => element.SetValue(IsFillProperty, value);
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/// <summary>
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/// 获取指定控件是否在FlexibleRowPanel中自动填充剩余空间的设置。
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/// </summary>
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/// <param name="element">要获取属性的UI元素。</param>
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/// <returns>布尔值，指示该控件是否被允许自动填充剩余空间。</returns>
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public static bool GetIsFill(UIElement element) => (bool)element.GetValue(IsFillProperty);
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private static void OnIsFillChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
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{
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if (d is UIElement element && (bool)e.NewValue)
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{
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element.SetValue(SpanProperty, 1.0);
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}
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}
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#endregion
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#region 4. 核心权重属性 (Span)
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/// <summary>
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/// 获取或设置控件在FlexibleRowPanel中的跨度。
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/// </summary>
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public static readonly DependencyProperty SpanProperty =
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DependencyProperty.RegisterAttached("Span", typeof(double), typeof(FlexibleRowPanel),
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new FrameworkPropertyMetadata(1.0, FrameworkPropertyMetadataOptions.AffectsParentMeasure));
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/// <summary>
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/// 设置指定控件在FlexibleRowPanel中的跨度。
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/// </summary>
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/// <param name="element">要设置属性的UI元素。</param>
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/// <param name="value">双精度浮点数，表示该控件在FlexibleRowPanel中的跨度。</param>
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public static void SetSpan(UIElement element, double value) => element.SetValue(SpanProperty, value);
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/// <summary>
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/// 获取控件在FlexibleRowPanel中的跨度。
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/// </summary>
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/// <param name="element">要获取跨度的UI元素。</param>
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/// <returns>返回一个double值，表示该控件在FlexibleRowPanel中的跨度。</returns>
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public static double GetSpan(UIElement element) => (double)element.GetValue(SpanProperty);
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#endregion
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private double GetEffectiveSpan(UIElement child)
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{
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var localValue = child.ReadLocalValue(SpanProperty);
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if (localValue != DependencyProperty.UnsetValue)
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{
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return (double)localValue;
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}
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return LayoutMode switch
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{
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FlexibleRowLayoutMode.Auto => -1.0,
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_ => 1.0,
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};
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}
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//protected override Size MeasureOverride(Size availableSize)
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//{
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// double spaceTakenByAutoChildren = 0;
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// double totalSpanForFillChildren = 0;
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// double maxHeight = 0;
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// // 【修改】计算所有间距占用的总宽度
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// var totalSpacing = Math.Max(0, InternalChildren.Count - 1) * Spacing;
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// // 【修改】计算真正可用于子控件的宽度
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// var effectiveWidth = Math.Max(0, availableSize.Width - totalSpacing);
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// // 第一遍测量：自动大小的控件
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// foreach (UIElement child in InternalChildren)
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// {
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// if (child == null) continue;
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// var span = GetEffectiveSpan(child);
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// if (span < 0)
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// {
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// child.Measure(new Size(double.PositiveInfinity, availableSize.Height));
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// spaceTakenByAutoChildren += child.DesiredSize.Width;
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// }
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// else
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// {
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// totalSpanForFillChildren += span;
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// }
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// }
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// var remainingWidth = Math.Max(0, effectiveWidth - spaceTakenByAutoChildren);
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// var widthPerSpanUnit = (totalSpanForFillChildren > 0 && !double.IsInfinity(remainingWidth)) ? remainingWidth / totalSpanForFillChildren : 0;
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// // 第二遍测量：比例填充的控件
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// foreach (UIElement child in InternalChildren)
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// {
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// if (child == null) continue;
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// var span = GetEffectiveSpan(child);
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// if (span >= 0)
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// {
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// child.Measure(new Size(widthPerSpanUnit * span, availableSize.Height));
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// }
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// if (child.DesiredSize.Height > maxHeight)
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// {
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// maxHeight = child.DesiredSize.Height;
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// }
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// }
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// // 返回的宽度应该是面板请求的总宽度
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// return new Size(availableSize.Width, maxHeight);
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//}
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/// <inheritdoc />
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protected override Size MeasureOverride(Size availableSize)
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{
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double totalAutoWidth = 0;
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double totalSpanUnits = 0;
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double maxHeight = 0;
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bool isWidthInfinite = double.IsInfinity(availableSize.Width);
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var childrenCount = InternalChildren.Count;
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var totalSpacing = Math.Max(0, childrenCount - 1) * Spacing;
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// 第一遍测量：收集信息
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foreach (UIElement child in InternalChildren)
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{
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if (child == null || child.Visibility == Visibility.Collapsed) continue;
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var span = GetEffectiveSpan(child);
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if (span < 0 || isWidthInfinite)
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{
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// 如果宽度是无穷大，或者子项是Auto，
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// 我们给它无穷大空间，看看它到底想占多大。
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child.Measure(new Size(double.PositiveInfinity, availableSize.Height));
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totalAutoWidth += child.DesiredSize.Width;
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}
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if (span >= 0)
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{
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totalSpanUnits += span;
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}
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}
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double finalWidth = 0;
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if (isWidthInfinite)
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{
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// 情况 A: 宽度无穷大 (例如在 StackPanel 或 ScrollViewer 中)
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// 此时 Span 的逻辑无法分配“剩余空间”，通常做法是让 Span 项以 DesiredSize 形式并存
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// 或者你可以给 Span 项一个默认基础宽度（比如 0，或者它们内容的宽度）
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// 这里我们把所有子项的 DesiredSize 加起来作为我们需要的总宽度
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finalWidth = totalAutoWidth + totalSpacing;
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// 既然是无穷大，我们需要再次测量那些还没有正确 Measure 的 Span 项（可选）
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foreach (UIElement child in InternalChildren)
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{
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if (child == null || child.Visibility == Visibility.Collapsed) continue;
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maxHeight = Math.Max(maxHeight, child.DesiredSize.Height);
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}
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}
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else
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{
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// 情况 B: 宽度是有限的 (正常的 Grid 或固定宽度的容器)
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double remainingWidth = Math.Max(0, availableSize.Width - totalSpacing - totalAutoWidth);
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double widthPerSpanUnit = totalSpanUnits > 0 ? remainingWidth / totalSpanUnits : 0;
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foreach (UIElement child in InternalChildren)
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{
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if (child == null || child.Visibility == Visibility.Collapsed) continue;
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var span = GetEffectiveSpan(child);
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if (span >= 0)
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{
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// 给 Span 项分配计算后的精确宽度
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child.Measure(new Size(widthPerSpanUnit * span, availableSize.Height));
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}
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maxHeight = Math.Max(maxHeight, child.DesiredSize.Height);
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}
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finalWidth = availableSize.Width; // 在有限宽度下，通常占用全部可用宽度
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}
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// 重要：返回计算出的有限尺寸，绝不返回 availableSize.Width (如果是 Infinity)
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return new Size(finalWidth, maxHeight);
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}
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/// <inheritdoc />
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protected override Size ArrangeOverride(Size finalSize)
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{
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double spaceTakenByAutoChildren = 0;
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double totalSpanForFillChildren = 0;
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// 【修改】计算所有间距占用的总宽度
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var totalSpacing = Math.Max(0, InternalChildren.Count - 1) * Spacing;
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// 【修改】计算真正可用于子控件的宽度
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var effectiveWidth = Math.Max(0, finalSize.Width - totalSpacing);
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// 重新计算一遍各项数值，因为 Measure 和 Arrange 的 Size 可能不同
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foreach (UIElement child in InternalChildren)
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{
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if (child == null) continue;
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var span = GetEffectiveSpan(child);
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if (span < 0)
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{
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spaceTakenByAutoChildren += child.DesiredSize.Width;
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}
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else
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{
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totalSpanForFillChildren += span;
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}
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}
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var remainingWidth = Math.Max(0, effectiveWidth - spaceTakenByAutoChildren);
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var widthPerSpanUnit = (totalSpanForFillChildren > 0) ? remainingWidth / totalSpanForFillChildren : 0;
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double currentX = 0;
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// 遍历并排列每个子元素
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for (var i = 0; i < InternalChildren.Count; i++)
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{
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var child = InternalChildren[i];
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if (child == null) continue;
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var span = GetEffectiveSpan(child);
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var childWidth = (span < 0) ? child.DesiredSize.Width : widthPerSpanUnit * span;
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child.Arrange(new Rect(currentX, 0, childWidth, finalSize.Height));
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// 【修改】移动 currentX，并为下一个控件加上间距
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currentX += childWidth;
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if (i < InternalChildren.Count - 1)
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{
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currentX += Spacing;
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}
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}
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return finalSize;
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}
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}
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} |