WPF 创建单个块的虚线椭圆

Question

有没有什么简单的方法可以创建一个由各个水平虚线组成的虚线椭圆，其中虚线的大小是一致的，并且可以指定它们的数量？

类似这样的：

我希望能够单独控制每个破折号，例如更改其颜色或将其绑定到我的视图模型中的操作。

我能想到的唯一方法是创建一个自定义控件，其中包含每个破折号的路径元素，共同组成一个椭圆形状，必须根据破折号的数量和大小计算路径数据椭圆的。

Answer 1

我现在回到这个问题，并设法以一种非常灵活和通用的方式解决它。此后需求有所变化，无需绑定，但可以轻松添加。

请注意，这是一个圆圈，这正是我想要的。这个问题真的应该说圆而不是椭圆，即使圆是椭圆，但我离题了......

这是我想出的 UserControl：

StatusRing.xaml.cs

public partial class StatusRing
{
    #region Dependency Property registrations

    public static readonly DependencyProperty DashesProperty = DependencyProperty.Register("Dashes",
        typeof(int), typeof(StatusRing), new PropertyMetadata(32, DashesChanged));

    public static readonly DependencyProperty DiameterProperty = DependencyProperty.Register("Diameter",
        typeof(double), typeof(StatusRing), new PropertyMetadata(150.00, DiameterChanged));

    public static readonly DependencyProperty DashHeightProperty = DependencyProperty.Register("DashHeight",
        typeof(double), typeof(StatusRing), new PropertyMetadata(20.00, DashHeightChanged));

    public static readonly DependencyProperty DashWidthProperty = DependencyProperty.Register("DashWidth",
        typeof(double), typeof(StatusRing), new PropertyMetadata(5.00, DashWidthChanged));

    public static readonly DependencyProperty DashFillProperty = DependencyProperty.Register("DashFill",
        typeof(SolidColorBrush), typeof(StatusRing), new PropertyMetadata(Brushes.DimGray, DashFillChanged));

    public static readonly DependencyProperty DashAccentFillProperty = DependencyProperty.Register("DashAccentFill",
        typeof(SolidColorBrush), typeof(StatusRing), new PropertyMetadata(Brushes.White, DashAnimationFillChanged));

    public static readonly DependencyProperty TailSizeProperty = DependencyProperty.Register("TailSize",
        typeof(int), typeof(StatusRing), new PropertyMetadata(10, TailSizeChanged));

    public static readonly DependencyProperty AnimationSpeedProperty = DependencyProperty.Register("AnimationSpeed",
        typeof(double), typeof(StatusRing), new PropertyMetadata(50.00, AnimationSpeedChanged));

    public static readonly DependencyProperty IsPlayingProperty = DependencyProperty.Register("IsPlaying",
        typeof(bool), typeof(StatusRing), new PropertyMetadata(false, IsPlayingChanged));

    #endregion Dependency Property registrations

    private readonly Storyboard glowAnimationStoryBoard = new Storyboard();

    public StatusRing()
    {
        Loaded += OnLoaded;
        InitializeComponent();
    }

    #region Dependency Properties

    public int Dashes
    {
        get => (int)GetValue(DashesProperty);
        set => SetValue(DashesProperty, value);
    }

    public double Diameter
    {
        get => (double)GetValue(DiameterProperty);
        set => SetValue(DiameterProperty, value);
    }

    public double Radius => Diameter / 2;

    public double DashHeight
    {
        get => (double)GetValue(DashHeightProperty);
        set => SetValue(DashHeightProperty, value);
    }

    public double DashWidth
    {
        get => (double)GetValue(DashWidthProperty);
        set => SetValue(DashWidthProperty, value);
    }

    public Brush DashFill
    {
        get => (SolidColorBrush)GetValue(DashFillProperty);
        set => SetValue(DashFillProperty, value);
    }

    public Brush DashAccentFill
    {
        get => (SolidColorBrush)GetValue(DashAccentFillProperty);
        set => SetValue(DashAccentFillProperty, value);
    }

    public int TailSize
    {
        get => (int)GetValue(TailSizeProperty);
        set => SetValue(TailSizeProperty, value);
    }

    public double AnimationSpeed
    {
        get => (double)GetValue(AnimationSpeedProperty);
        set => SetValue(AnimationSpeedProperty, value);
    }

    public bool IsPlaying
    {
        get => (bool)GetValue(IsPlayingProperty);
        set => SetValue(IsPlayingProperty, value);
    }

    #endregion Dependency Properties

    private void OnLoaded(object sender, RoutedEventArgs e)
    {
        var thisControl = sender as StatusRing;
        Recreate(thisControl);
    }

    #region Dependency Property callbacks

    private static void DashesChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
    {
        var thisControl = d as StatusRing;
        Recreate(thisControl);
    }

    private static void DiameterChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
    {
        var thisControl = d as StatusRing;
        Recreate(thisControl);
    }

    private static void DashHeightChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
    {
        var thisControl = d as StatusRing;
        Recreate(thisControl);
    }

    private static void DashWidthChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
    {
        var thisControl = d as StatusRing;
        Recreate(thisControl);
    }

    private static void DashFillChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
    {
        var thisControl = d as StatusRing;
        Recreate(thisControl);
    }

    private static void DashAnimationFillChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
    {
        var thisControl = d as StatusRing;
        Recreate(thisControl);
    }

    private static void TailSizeChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
    {
        var thisControl = d as StatusRing;
        Recreate(thisControl);
    }

    private static void AnimationSpeedChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
    {
        var thisControl = d as StatusRing;
        if (thisControl.IsLoaded)
        {
            thisControl.glowAnimationStoryBoard.Stop();
            thisControl.glowAnimationStoryBoard.Children.Clear();

            ApplyAnimations(thisControl);

            thisControl.glowAnimationStoryBoard.Begin();
        }
    }

    private static void IsPlayingChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
    {
        var thisControl = d as StatusRing;
        if (thisControl.IsLoaded)
        {
            var isPlaying = (bool)e.NewValue;
            if (isPlaying)
            {
                thisControl.glowAnimationStoryBoard.Begin();
            }
            else
            {
                thisControl.glowAnimationStoryBoard.Stop();
            }
        }
    }

    #endregion Dependency Property callbacks

    private static void Recreate(StatusRing thisControl)
    {
        if (thisControl.IsLoaded)
        {
            thisControl.glowAnimationStoryBoard.Stop();
            thisControl.glowAnimationStoryBoard.Children.Clear();
            thisControl.RootCanvas.Children.Clear();

            Validate(thisControl);
            BuildRing(thisControl);

            ApplyAnimations(thisControl);

            if (thisControl.IsPlaying)
            {
                thisControl.glowAnimationStoryBoard.Begin();
            }
            else
            {
                thisControl.glowAnimationStoryBoard.Stop();
            }
        }
    }

    private static void Validate(StatusRing thisControl)
    {
        if (thisControl.TailSize > thisControl.Dashes)
        {
            throw new Exception("TailSize cannot be larger than amount of dashes");
        }
    }

    private static void BuildRing(StatusRing thisControl)
    {
        var angleStep = (double)360 / thisControl.Dashes;

        for (double i = 0; i < 360; i = i + angleStep)
        {
            var rect = new Rectangle
            {
                Fill = thisControl.DashFill,
                Height = thisControl.DashHeight,
                Width = thisControl.DashWidth
            };

            //Rotate dash to follow circles circumference 
            var centerY = thisControl.Radius;
            var centerX = thisControl.DashWidth / 2;
            var rotateTransform = new RotateTransform(i, centerX, centerY);
            rect.RenderTransform = rotateTransform;

            var offset = thisControl.Radius - thisControl.DashWidth / 2;
            rect.SetValue(Canvas.LeftProperty, offset);

            thisControl.RootCanvas.Children.Add(rect);
        }

        thisControl.RootCanvas.Width = thisControl.Diameter;
        thisControl.RootCanvas.Height = thisControl.Diameter;
    }

    private static void ApplyAnimations(StatusRing thisControl)
    {
        var baseColor = ((SolidColorBrush)thisControl.DashFill).Color;
        var animatedColor = ((SolidColorBrush)thisControl.DashAccentFill).Color;

        var dashes = thisControl.RootCanvas.Children.OfType<Rectangle>().ToList();

        double animationPeriod = thisControl.AnimationSpeed;
        double glowDuration = animationPeriod * thisControl.TailSize;

        for (int i = 0; i < dashes.Count; i++)
        {
            var beginTime = TimeSpan.FromMilliseconds(animationPeriod * i);

            var colorAnimation = new ColorAnimationUsingKeyFrames
            {
                BeginTime = beginTime,
                RepeatBehavior = RepeatBehavior.Forever
            };

            var toFillColor = new LinearColorKeyFrame(animatedColor, TimeSpan.Zero);
            colorAnimation.KeyFrames.Add(toFillColor);

            var dimToBase = new LinearColorKeyFrame(baseColor, TimeSpan.FromMilliseconds(glowDuration));
            colorAnimation.KeyFrames.Add(dimToBase);

            var restingTime = animationPeriod * dashes.Count;
            var delay = new LinearColorKeyFrame(baseColor, TimeSpan.FromMilliseconds(restingTime));
            colorAnimation.KeyFrames.Add(delay);

            Storyboard.SetTarget(colorAnimation, dashes[i]);
            Storyboard.SetTargetProperty(colorAnimation, new PropertyPath("(Fill).(SolidColorBrush.Color)"));

            thisControl.glowAnimationStoryBoard.Children.Add(colorAnimation);
        }
    }
}

StatusRing.xaml：

<UserControl x:Class="WpfPlayground.StatusRing"
         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" 
         xmlns:d="http://schemas.microsoft.com/expression/blend/2008" 
         mc:Ignorable="d" 
         d:DesignHeight="450" d:DesignWidth="800">
<Canvas x:Name="RootCanvas" />

用法：

<local:StatusRing Diameter="250" 
                  Dashes="32"
                  TailSize="16"
                  IsPlaying="True" />

结果：

破折号的数量，动画的长度和速度等......都是可配置的。不过，依赖属性的命名可能会更好......

享受:-)