78 lines
3.1 KiB
C#
78 lines
3.1 KiB
C#
using System.Windows.Documents;
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namespace Melskin.Controls;
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#region Internal Implementation
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internal class WindowHost : IToastHost
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{
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private readonly StackPanel toastContainer;
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public WindowHost(Window window)
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{
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toastContainer = new StackPanel();
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// Use a style to apply margin between toasts, which is a robust approach.
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var childStyle = new Style(typeof(ToastControl));
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childStyle.Setters.Add(new Setter(FrameworkElement.MarginProperty, new Thickness(0, 8, 0, 8)));
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toastContainer.Resources.Add(typeof(ToastControl), childStyle);
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var adornerLayer = AdornerLayer.GetAdornerLayer(window.Content as Visual);
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if (adornerLayer == null) throw new InvalidOperationException("在指定的窗口中找不到 AdornerLayer。");
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adornerLayer.Add(new ToastAdorner(window.Content as UIElement, toastContainer));
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}
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public void AddToast(ToastControl toast) => toastContainer.Children.Add(toast);
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public void RemoveToast(ToastControl toast) => toastContainer.Children.Remove(toast);
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private class ToastAdorner : Adorner
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{
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private readonly UIElement child; // This is our StackPanel
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public ToastAdorner(UIElement? adornedElement, UIElement child) : base(adornedElement)
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{
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this.child = child;
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// Add the child to the visual tree. This is essential.
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AddVisualChild(this.child);
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}
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protected override int VisualChildrenCount => 1;
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protected override Visual GetVisualChild(int index) => child;
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// We override Measure to tell our child (StackPanel) how much space it has.
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protected override Size MeasureOverride(Size constraint)
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{
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// Give the child all the space it could possibly want.
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// It will then measure itself and its children, establishing its DesiredSize.
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child.Measure(new Size(double.PositiveInfinity, double.PositiveInfinity));
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// The Adorner itself doesn't need to return a specific size, as it's a transparent overlay.
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return base.MeasureOverride(constraint);
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}
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// ArrangeOverride is where we do the actual positioning.
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protected override Size ArrangeOverride(Size finalSize)
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{
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// 'finalSize' is the full size of the element we are adorning (e.g., the window's content area).
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// '_child.DesiredSize' is the size our StackPanel reported it needs after being measured.
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// Calculate the X coordinate to center the child (StackPanel).
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var x = (finalSize.Width - child.DesiredSize.Width) / 2;
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// The Y coordinate is 0, placing it at the very top.
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double y = 0;
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// Create the final rectangle for our child, positioned correctly.
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var finalRect = new Rect(new Point(x, y), child.DesiredSize);
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// Arrange the child (our StackPanel) in the calculated centered rectangle.
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child.Arrange(finalRect);
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// The Adorner itself arranges to fill the entire space.
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return finalSize;
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}
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}
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}
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#endregion
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