.net – 如何使椭圆闪烁？

<UserControl x:Class="WpfAnimation.LED"
xmlns="http://scheR_844_11845@as.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://scheR_844_11845@as.microsoft.com/winfx/2006/xaml"
Height="300" Width="300">

<Grid>
    <Ellipse x:Name="MyLight" Height="Auto" Width="Auto"/>
</Grid>

</UserControl>

解决方法@H_696_31@

您可以使用自动反转和重复的动画执行此操作(这适用于Silverlight)：

<UserControl
    xmlns="http://scheR_844_11845@as.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://scheR_844_11845@as.microsoft.com/winfx/2006/xaml"
    x:Class="Blinker.MainPage"
    Width="640" Height="480" Loaded="UserControl_Loaded">
    <UserControl.resources>
        <Storyboard x:Name="Blink" AutoReverse="True" RepeatBehavior="Forever">
            <ColorAnimationUsingKeyFrames BeginTime="00:00:00"
              Storyboard.TargetName="ellipse"
              Storyboard.TargetProperty="(Shape.Fill).(SolidColorBrush.Color)">
                 <EasingColorKeyFrame KeyTime="00:00:01" Value="Gray"/>
            </ColorAnimationUsingKeyFrames>
         </Storyboard>
    </UserControl.resources>
    <Grid x:Name="LayoutRoot" BACkground="White">
         <Ellipse x:Name="ellipse" Fill="Green" stroke="Black"/>
    </Grid>
</UserControl>

然后在控件加载或设置属性时启动动画 – 除非你不需要依赖属性

private bool blinking;
public bool IsBlinking
{
    get
    {
       return blinking;
    }
    set
    {
        if (value)
        {
             this.blink.begin();
        }
        else
        {
             this.blink.Stop();
        }

        this.blinking = value;
    }
}

或在启动时：

private void UserControl_Loaded(object sender,System.Windows.RoutedEventArgs E)
{
    this.blink.begin();
}

这是另一种在WPF中使用VisualStateManager的方法 – 它也适用于Silverlight：

<UserControl
xmlns="http://scheR_844_11845@as.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://scheR_844_11845@as.microsoft.com/winfx/2006/xaml"
xmlns:d="http://scheR_844_11845@as.microsoft.com/expression/blend/2008"
xmlns:mc="http://scheR_844_11845@as.openxmlformats.org/markup-compatibility/2006"
mc:Ignorable="d"
x:Class="BlinkerApp.blinker"
x:Name="UserControl"
d:DesignWidth="100" d:DesignHeight="100">
<Grid x:Name="LayoutRoot">
    <VisualStateManager.VisualStateGroups>
        <VisualStateGroup x:Name="BlinkStates">
            <VisualState x:Name="Blinking">
                <Storyboard AutoReverse="True" RepeatBehavior="Forever">
                    <ColorAnimationUsingKeyFrames BeginTime="00:00:00" Storyboard.TargetName="ellipse" Storyboard.TargetProperty="(Shape.Fill).(SolidColorBrush.Color)">
                        <SplineColorKeyFrame KeyTime="00:00:01" Value="Gray"/>
                    </ColorAnimationUsingKeyFrames>
                </Storyboard>
            </VisualState>
            <VisualState x:Name="Stopped"/>
        </VisualStateGroup>
    </VisualStateManager.VisualStateGroups>
    <Ellipse x:Name="ellipse" Fill="Green" stroke="Black"/>
</Grid>

然后让IsBlinking属性切换视觉状态：

namespace BlinkerApp
{
    using System.Windows;
    using System.Windows.Controls;

/// <sumMary>
/// Interaction logic for Blinker.xaml
/// </sumMary>
public partial class Blinker : UserControl
{
    private bool blinking;

    public Blinker()
    {
        this.InitializeComponent();
    }

    public bool IsBlinking
    {    
        get    
        {       
            return blinking;    
        }    

        set    
        {        
            if (value)        
            {
                VisualStateManager.GoToState(this,"Blinking",truE);
            }        
            else        
            {
                VisualStateManager.GoToState(this,"Stopped",truE);
            }        

            this.blinking = value;    
        }
    }       
}
}