c# - 如何停止动画WPF？

Question

如何停止动画以使其不会产生 Completed 事件。这是一个简单的例子

<Window x:Class="WpfApplication5.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        Title="MainWindow" Height="248" Width="318">
    <Grid>
        <Border Width="20" Height="20" Background="Red" MouseEnter="Border_MouseEnter" MouseLeave="Border_MouseLeave" x:Name="border" />
    </Grid>
</Window>

和支持代码:

private void Border_MouseEnter(object sender, MouseEventArgs e)
{
    var a = new DoubleAnimation { To = 0, Duration = TimeSpan.FromMilliseconds(4000) };
    a.Completed += (obj, args) => MessageBox.Show("Boom!");
    border.BeginAnimation(Border.OpacityProperty, a);
}

private void Border_MouseLeave(object sender, MouseEventArgs e)
{
    border.BeginAnimation(Border.OpacityProperty, null);
    border.Opacity = 1;
}

如果我在矩形变白之前将鼠标移出，它仍会在一段时间后显示弹出窗口。如何防止这种情况？假设 Border_MouseLeave 和 Border_MouseEnter 方法彼此不了解(它们不能将动画实例变量传递给彼此)。

Answer 1

你可以使用这个:

<Border Width="20" Height="20" Background="Red" x:Name="border" >
                <Border.Triggers>
                    <EventTrigger RoutedEvent="MouseEnter">
                        <BeginStoryboard Name="Ali">
                            <Storyboard>
                                <DoubleAnimation To="0" Duration="0:0:4" Completed="com" Storyboard.TargetProperty="Opacity"/>
                            </Storyboard>
                        </BeginStoryboard>
                    </EventTrigger>
                    <EventTrigger RoutedEvent="MouseLeave">
                        <StopStoryboard  BeginStoryboardName="Ali"/>
                    </EventTrigger>
                </Border.Triggers>
            </Border>

和:

private void com(object sender, EventArgs e)
        {
            MessageBox.Show("boom!");
        }