C# 默认情况下隐藏元素，然后在单击时设置动画

有没有办法将XAML中的元素设置为隐藏？当用户点击一个新的游戏按钮时，我想要一组按钮（可能在堆栈面板中）在视图中动画化，让用户选择难度级别。我尝试将可见性设置为“折叠”，但当我使用内置的Win8动画（如EntertheMeTransition或PopIn）时，折叠的元素不会显示。将不透明度更改为0，然后尝试使用其中一个设置动画效果相同。

可见性属性独立于不透明度工作。在运行自定义的

Opacity

动画或内置的

FadeInThemeAnimation

之前，需要将

Visibility

设置回

Visibility

您可以使用WinRT XAML工具包扩展运行以下简单动画：

myElement.Visibility = Visibility.Visible;
myElement.FadeInCustom();

XAML工具包中的扩展方法类：

using System;
using System.Threading.Tasks;
using WinRTXamlToolkit.AwaitableUI;
using Windows.UI.Xaml;
using Windows.UI.Xaml.Media.Animation;

namespace WinRTXamlToolkit.Controls.Extensions
{
    /// <summary>
    /// Extension methods and attached properties for UIElement class.
    /// </summary>
    public static class UIElementAnimationExtensions
    {
        #region AttachedFadeStoryboard
        /// <summary>
        /// AttachedFadeStoryboard Attached Dependency Property
        /// </summary>
        public static readonly DependencyProperty AttachedFadeStoryboardProperty =
            DependencyProperty.RegisterAttached(
                "AttachedFadeStoryboard",
                typeof(Storyboard),
                typeof(UIElementAnimationExtensions),
                new PropertyMetadata(null, OnAttachedFadeStoryboardChanged));

        /// <summary>
        /// Gets the AttachedFadeStoryboard property. This dependency property 
        /// indicates the currently running custom fade in/out storyboard.
        /// </summary>
        private static Storyboard GetAttachedFadeStoryboard(DependencyObject d)
        {
            return (Storyboard)d.GetValue(AttachedFadeStoryboardProperty);
        }

        /// <summary>
        /// Sets the AttachedFadeStoryboard property. This dependency property 
        /// indicates the currently running custom fade in/out storyboard.
        /// </summary>
        private static void SetAttachedFadeStoryboard(DependencyObject d, Storyboard value)
        {
            d.SetValue(AttachedFadeStoryboardProperty, value);
        }

        /// <summary>
        /// Handles changes to the AttachedFadeStoryboard property.
        /// </summary>
        /// <param name="d">
        /// The <see cref="DependencyObject"/> on which
        /// the property has changed value.
        /// </param>
        /// <param name="e">
        /// Event data that is issued by any event that
        /// tracks changes to the effective value of this property.
        /// </param>
        private static void OnAttachedFadeStoryboardChanged(
            DependencyObject d, DependencyPropertyChangedEventArgs e)
        {
            Storyboard oldAttachedFadeStoryboard = (Storyboard)e.OldValue;
            Storyboard newAttachedFadeStoryboard = (Storyboard)d.GetValue(AttachedFadeStoryboardProperty);
        }
        #endregion

        #region FadeIn()
        /// <summary>
        /// Fades the element in using the FadeInThemeAnimation.
        /// </summary>
        /// <remarks>
        /// Opacity property of the element is not affected.<br/>
        /// The duration of the visible animation itself is not affected by the duration parameter. It merely indicates how long the Storyboard will run.<br/>
        /// If FadeOutThemeAnimation was not used on the element before - nothing will happen.<br/>
        /// </remarks>
        /// <param name="element"></param>
        /// <param name="duration"></param>
        /// <returns></returns>
        public static async Task FadeIn(this UIElement element, TimeSpan? duration = null)
        {
            ((FrameworkElement)element).Visibility = Visibility.Visible;
            var fadeInStoryboard = new Storyboard();
            var fadeInAnimation = new FadeInThemeAnimation();

            if (duration != null)
            {
                fadeInAnimation.Duration = duration.Value;
            }

            Storyboard.SetTarget(fadeInAnimation, element);
            fadeInStoryboard.Children.Add(fadeInAnimation);
            await fadeInStoryboard.BeginAsync();
        } 
        #endregion

        #region FadeOut()
        /// <summary>
        /// Fades the element out using the FadeOutThemeAnimation.
        /// </summary>
        /// <remarks>
        /// Opacity property of the element is not affected.<br/>
        /// The duration of the visible animation itself is not affected by the duration parameter. It merely indicates how long the Storyboard will run.<br/>
        /// If FadeOutThemeAnimation was already run before and FadeInThemeAnimation was not run after that - nothing will happen.<br/>
        /// </remarks>
        /// <param name="element"></param>
        /// <param name="duration"></param>
        /// <returns></returns>
        public static async Task FadeOut(this UIElement element, TimeSpan? duration = null)
        {
            var fadeOutStoryboard = new Storyboard();
            var fadeOutAnimation = new FadeOutThemeAnimation();

            if (duration != null)
            {
                fadeOutAnimation.Duration = duration.Value;
            }

            Storyboard.SetTarget(fadeOutAnimation, element);
            fadeOutStoryboard.Children.Add(fadeOutAnimation);
            await fadeOutStoryboard.BeginAsync();
        } 
        #endregion

        #region FadeInCustom()
        /// <summary>
        /// Fades the element in using a custom DoubleAnimation of the Opacity property.
        /// </summary>
        /// <param name="element"></param>
        /// <param name="duration"></param>
        /// <param name="easingFunction"> </param>
        /// <returns></returns>
        public static async Task FadeInCustom(this UIElement element, TimeSpan? duration = null, EasingFunctionBase easingFunction = null, double targetOpacity = 1.0)
        {
            CleanUpPreviousFadeStoryboard(element);

            var fadeInStoryboard = new Storyboard();
            var fadeInAnimation = new DoubleAnimation();

            if (duration == null)
                duration = TimeSpan.FromSeconds(0.4);

            fadeInAnimation.Duration = duration.Value;
            fadeInAnimation.To = targetOpacity;
            fadeInAnimation.EasingFunction = easingFunction;

            Storyboard.SetTarget(fadeInAnimation, element);
            Storyboard.SetTargetProperty(fadeInAnimation, "Opacity");
            fadeInStoryboard.Children.Add(fadeInAnimation);
            SetAttachedFadeStoryboard(element, fadeInStoryboard);
            await fadeInStoryboard.BeginAsync();
            element.Opacity = targetOpacity;
            fadeInStoryboard.Stop();
        }
        #endregion

        #region FadeOutCustom()
        /// <summary>
        /// Fades the element out using a custom DoubleAnimation of the Opacity property.
        /// </summary>
        /// <param name="element"></param>
        /// <param name="duration"></param>
        /// <param name="easingFunction"> </param>
        /// <returns></returns>
        public static async Task FadeOutCustom(this UIElement element, TimeSpan? duration = null, EasingFunctionBase easingFunction = null)
        {
            CleanUpPreviousFadeStoryboard(element); 

            var fadeOutStoryboard = new Storyboard();
            var fadeOutAnimation = new DoubleAnimation();

            if (duration == null)
                duration = TimeSpan.FromSeconds(0.4);

            fadeOutAnimation.Duration = duration.Value;
            fadeOutAnimation.To = 0.0;
            fadeOutAnimation.EasingFunction = easingFunction;

            Storyboard.SetTarget(fadeOutAnimation, element);
            Storyboard.SetTargetProperty(fadeOutAnimation, "Opacity");
            fadeOutStoryboard.Children.Add(fadeOutAnimation);
            SetAttachedFadeStoryboard(element, fadeOutStoryboard);
            await fadeOutStoryboard.BeginAsync();
            element.Opacity = 0.0;
            fadeOutStoryboard.Stop();
        } 
        #endregion

        #region CleanUpPreviousFadeStoryboard()
        public static void CleanUpPreviousFadeStoryboard(this UIElement element)
        {
            var attachedFadeStoryboard = GetAttachedFadeStoryboard(element);

            if (attachedFadeStoryboard != null)
            {
                attachedFadeStoryboard.Stop();
            }
        }
        #endregion
    }
}

使用系统；
使用System.Threading.Tasks；
使用WinRTXamlToolkit.AwaitableUI；
使用Windows.UI.Xaml；
使用Windows.UI.Xaml.Media.Animation；
命名空间WinRTXamlToolkit.Controls.Extensions
{
/// 
///UIElement类的扩展方法和附加属性。
/// 
公共静态类UIElementAnimationExtensions
{
#区域附加视频情节提要
/// 
///AttachedFadeStoryboard附加的依赖项属性
/// 
公共静态只读从属属性AttachedFadstoryBoardProperty=
DependencyProperty.RegisterAttached(
“AttachedFadeStoryboard”，
类型（故事板），
类型（UIElementAnimationExtensions），
新的PropertyMetadata（null，OnAttachedFadeStoryboardChanged））；
/// 
///获取AttachedFadeStoryboard属性。此依赖项属性
///指示当前正在运行的自定义淡入/淡出情节提要。
/// 
私有静态情节提要GetAttachedFadeStoryboard（DependencyObject d）
{
返回（情节提要）d.GetValue（AttachedFadeStoryboard属性）；
}
/// 
///设置AttachedFadeStoryboard属性。此依赖项属性
///指示当前正在运行的自定义淡入/淡出情节提要。
/// 
私有静态void SetAttachedFadeStoryboard（DependencyObject d，Storyboard值）
{
d、 SetValue（AttachedFadeStoryboard属性，值）；
}
/// 
///处理对AttachedFadeStoryboard属性的更改。
/// 
/// 
///上面的
///属性的值已更改。
/// 
/// 
///由以下事件发布的事件数据：
///跟踪对此属性的有效值所做的更改。
/// 
TachedFadeStoryboard上的私有静态无效已更改(
DependencyObject d，DependencyPropertyChangedEventArgs e）
{
故事板oldAttachedFadeStoryboard=（故事板）e.OldValue；
情节提要newAttachedFadeStoryboard=（情节提要）d.GetValue（AttachedFadeStoryboard属性）；
}
#端区
#区域法代因（）
/// 
///使用FadeInTheme动画使元素淡入淡出。
/// 
/// 
///元素的不透明度属性不受影响。

///可见动画本身的持续时间不受持续时间参数的影响。它仅指示故事板将运行多长时间。

///如果之前未在元素上使用淡出，则不会发生任何情况。

/// 
/// 
/// 
/// 
公共静态异步任务FadeIn（此UIElement元素，TimeSpan？duration=null）
{
（（FrameworkElement）元素）。可见性=可见性。可见；
var fadeInStoryboard=新故事板（）；
var fadeInAnimation=新的FadeInThemeAnimation（）；
if（持续时间！=null）
{
fadeInAnimation.Duration=Duration.Value；
}
故事板.SetTarget（fadeInAnimation，元素）；
FadeInnstoryBoard.Children.Add（fadeInAnimation）；
等待FadeInstalleryBoard.BeginAsync（）；
} 
#端区
#区域衰减（）
/// 
///使用“淡出”选项淡出元素。
/// 
/// 
///元素的不透明度属性不受影响。

///可见动画本身的持续时间不受持续时间参数的影响。它仅指示故事板将运行多长时间。

///如果FadeOutThemeAnimation在此之前已运行，而FadeInThemeAnimation在此之后未运行-则不会发生任何事情。

/// 
/// 
/// 
/// 
公共静态异步任务淡出（此UIElement元素，TimeSpan？duration=null）
{
var fadeOutStoryboard=新故事板（）；
var fadeutanimation=新的fadeutthemeanimation（）；
if（持续时间！=null）
{
fadeOutAnimation.Duration=Duration.Value；
}
情节提要.SetTarget（淡出动画，元素）；
fadeOutStoryboard.Children.Add（fadeOutAnimation）；
等待衰减Toryboard.BeginAsync（）；
} 
#端区
#区域FadeInCustom（）
/// 
///使用“不透明度”特性的自定义动画淡入元素。
/// 
/// 
/// 
///  
/// 
公共静态异步任务FadeInCustom（此UIElement元素，TimeSpan？duration=null，EasingFunctionBase easingFunction=null，double TargetCapacity=1.0）
{
CleanUpPreviousFadeStoryboard（元件）；
var fadeInStoryboard=新故事板（）；
var fadeInAnimation=new DoubleAnimation（）；
if（持续时间==null）
持续时间=从秒开始的时间跨度（0.4）；
法代纳