Shape流动效果

<Window x:Class="MvvmLight1.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
        xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
        xmlns:localBehavior="clr-namespace:MvvmLight1"
        xmlns:i="http://schemas.microsoft.com/expression/2010/interactivity"
        xmlns:ignore="http://www.ignore.com"
        mc:Ignorable="d ignore"
        Height="400"
        Width="600"
        Title="MVVM Light Application"
        DataContext="{Binding Main, Source={StaticResource Locator}}">

    <Window.Resources>
        <ResourceDictionary>
            <ResourceDictionary.MergedDictionaries>
                <ResourceDictionary Source="Skins/MainSkin.xaml" />
            </ResourceDictionary.MergedDictionaries>
        </ResourceDictionary>
    </Window.Resources>


    <StackPanel>
        <Ellipse StrokeDashArray="2,4" Stroke="Red" StrokeThickness="3" Height="100" Width="100">
            <i:Interaction.Behaviors>
                <localBehavior:FluidBehavior FlowRate="{Binding ElementName=FlowRate,Path=Value}" 
                                                 WhetherFluid="{Binding ElementName=FluidCheckBox, Path=IsChecked}"/>
            </i:Interaction.Behaviors>
        </Ellipse>
        <Rectangle StrokeDashArray="1,2" Stroke="Blue" StrokeThickness="3" Height="100" Width="100">
            <i:Interaction.Behaviors>
                <localBehavior:FluidBehavior FlowRate="{Binding ElementName=FlowRate,Path=Value}" 
                                                 WhetherFluid="{Binding ElementName=FluidCheckBox, Path=IsChecked}"/>
            </i:Interaction.Behaviors>
        </Rectangle>
        <Path x:Name="MyPath"
              StrokeThickness="3"
              StrokeDashArray="5,10"
              Stroke="Black">
            <i:Interaction.Behaviors>
                <localBehavior:FluidBehavior FlowRate="{Binding ElementName=FlowRate,Path=Value}" 
                                                 WhetherFluid="{Binding ElementName=FluidCheckBox, Path=IsChecked}"/>
            </i:Interaction.Behaviors>
            <Path.Data>
                <PathGeometry Figures="M 10,100 C 10,300 300,-160 300,100" />
            </Path.Data>
        </Path>
        <StackPanel>
            <CheckBox x:Name="FluidCheckBox" Content="流动效果"/>
            <Slider x:Name="FlowRate" Minimum="1" Maximum="10"/>
            <TextBlock Text="{Binding ElementName=FlowRate,Path=Value}"/>
        </StackPanel>
    </StackPanel>

</Window>

由Xaml可以看出核心就是一个FluidBehavior，效果，就不过多阐述了

最核心的就是用一个定时器对于Shape的StrokeDashOffset进行改变，其中抽象FlowRate以及WhetherFluid用于控制流动速率以及是否流动

using System;
using System.Windows;
using System.Windows.Interactivity;
using System.Windows.Shapes;
using System.Windows.Threading;

namespace MvvmLight1
{
    /// <summary>
    /// 流动行为
    /// </summary>
    public class FluidBehavior : Behavior<Shape>
    {
        #region 依赖属性

        /// <summary>
        /// 流动速度
        /// </summary>
        public int FlowRate
        {
            get { return (int)GetValue(FlowRateProperty); }
            set { SetValue(FlowRateProperty, value); }
        }

        // Using a DependencyProperty as the backing store for FlowRate.  This enables animation, styling, binding, etc...
        public static readonly DependencyProperty FlowRateProperty =
            DependencyProperty.Register("FlowRate", typeof(int), typeof(FluidBehavior), new PropertyMetadata(1));

        /// <summary>
        /// 是否流动
        /// </summary>
        public bool WhetherFluid
        {
            get { return (bool)GetValue(WhetherFluidProperty); }
            set { SetValue(WhetherFluidProperty, value); }
        }

        // Using a DependencyProperty as the backing store for WhetherFluid.  This enables animation, styling, binding, etc...
        public static readonly DependencyProperty WhetherFluidProperty =
            DependencyProperty.Register("WhetherFluid", typeof(bool), typeof(FluidBehavior), new PropertyMetadata(true, OnWhetherFluidChanged));

        private static void OnWhetherFluidChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
        {
            var behavior = d as FluidBehavior;
            if (Convert.ToBoolean(e.NewValue))
            {
                behavior._timer.Start();
            }
            else
            {
                behavior._timer.Stop();
            }
        }

        #endregion

        protected override void OnAttached()
        {
            base.OnAttached();
            Fluid();
        }

        private readonly DispatcherTimer _timer = new DispatcherTimer();

        //流动
        private void Fluid()
        {
            _timer.Tick += (sender, e) =>
            {
                AssociatedObject.StrokeDashOffset -= FlowRate;
            };
            _timer.Interval = TimeSpan.FromSeconds(1d / 60);
            if (WhetherFluid)
            {
                _timer.Start();
            }
        }
    }
}