WPF实现动画的几种方式及其小案例

WPF实现动画的方式：

1. 基于计时器的动画

建立一个定时器，然后根据其频率循环调用函数或者一个事件处理函数，在这个函数中可以手工更新目标属性，直到达到最终值，这时可以停止计时器。

案例：

效果图：

XAML：

<Window x:Class="WpfDispatcherTimerAnimation.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:local="clr-namespace:WpfDispatcherTimerAnimation"
        mc:Ignorable="d"
        Title="MainWindow" Height="" Width="">
    <Grid>
        <Grid.RowDefinitions>
            <RowDefinition/>
            <RowDefinition/>
        </Grid.RowDefinitions>
        <Ellipse Name="rectangle" Height="" Width=""  Fill="Aquamarine"/>
        <Button  Content="开启动画" Click="ButtonBase_OnClick" Height="" Width="" Grid.Row=""/>
    </Grid>
</Window>

C#代码：

using System;
using System.Windows;
using System.Windows.Threading;

namespace WpfDispatcherTimerAnimation
{
    /// <summary>
    /// MainWindow.xaml 的交互逻辑
    /// </summary>
    public partial class MainWindow : Window
    {
        public MainWindow()
        {
            InitializeComponent();
        }
        /// <summary>
        /// 长方形减小计时器
        /// </summary>
        DispatcherTimer dispatcherTimerDecrease = new DispatcherTimer();

        /// <summary>
        /// 长方形增大计时器
        /// </summary>
        DispatcherTimer dispatcherTimerIncrease = new DispatcherTimer();

        /// <summary>
        /// 按钮点击事件
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void ButtonBase_OnClick(object sender, RoutedEventArgs e)
        {
            dispatcherTimerIncrease.Interval = TimeSpan.FromMilliseconds();
            dispatcherTimerIncrease.Tick += dispatcherTimerIncrease_Tick;
            dispatcherTimerIncrease.Start();
            dispatcherTimerDecrease.Interval = TimeSpan.FromMilliseconds();
            dispatcherTimerDecrease.Tick += DispatcherTimerDecrease_Tick;
        }

        /// <summary>
        /// 增加计时器事件
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void DispatcherTimerDecrease_Tick(object sender, EventArgs e)
        {
            if (rectangle.Width <  || rectangle.Height < )
            {
                (sender as DispatcherTimer).Stop();
                dispatcherTimerIncrease.Start();
            }
            else if (rectangle.Width >=  || rectangle.Height >= )
            {
                rectangle.Width -= ;
                rectangle.Height -= ;
            }
        }

        /// <summary>
        /// 减少计时器事件
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void dispatcherTimerIncrease_Tick(object sender, EventArgs e)
        {
            if (rectangle.Width <  || rectangle.Height < )
            {
                rectangle.Width += ;
                rectangle.Height += ;
            }
            else if (rectangle.Width >=  || rectangle.Height >= )
            {
                (sender as DispatcherTimer).Stop();
                dispatcherTimerDecrease.Start();
            }
        }
    }
}

2.基于桢的动画

由CompositionTarget类来完成，它提供了一个回调函数（Rendering的事件处理函数），WPF会在每次界面刷新时调用该回调函数。CompositionTarget的刷新率与窗体保持一致，因此很难人工控制动画的快慢。

案例：

效果图：

XAML：

<Window x:Class="Wpf基于桢的动画.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:local="clr-namespace:Wpf基于桢的动画"
        mc:Ignorable="d"
        Title="MainWindow" Height="" Width="">
    <Grid >
        <Grid.RowDefinitions>
            <RowDefinition/>
            <RowDefinition/>
        </Grid.RowDefinitions>
        <Ellipse Name="ellipse" Height="" Width=""  Fill="Aquamarine"/>
        <Button Grid.Row=""  Content="开启动画" Height="" Width=""  Click="ButtonBase_OnClick" />
    </Grid>
</Window>

C#：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Navigation;
using System.Windows.Shapes;
using System.Windows.Threading;

namespace Wpf基于桢的动画
{
    /// <summary>
    /// MainWindow.xaml 的交互逻辑
    /// </summary>
    public partial class MainWindow : Window
    {
        public MainWindow()
        {
            InitializeComponent();
        }

        private void ButtonBase_OnClick(object sender, RoutedEventArgs e)
        {
            CompositionTarget.Rendering+=new EventHandler(CompositionTarget_Rendering);
        }

        private void CompositionTarget_Rendering(object sender, EventArgs e)
        {
            if (ellipse.Width <  || ellipse.Height < )
            {
                ellipse.Width += ;
                ellipse.Height += ;
            }
            else if (ellipse.Width >=  || ellipse.Height >= )
            {
              CompositionTarget.Rendering-=new EventHandler(CompositionTarget_Rendering);
            }
        }
    }
}

3.基于属性的动画

用一个DoubleAnimation类制定起始值（From=“”）、终点值To=“”、时间（Duration=“0:0:2.7”），以及动画结束应该（FillBehavior=”Stop”）。设置好之后该矩形调用BeginAnimation方法开始实现动画，BeginAnimation制定需要应用动画的属性和创建的DoubleAnimation。

案例：

效果图：

XAML：

<Window x:Class="Wpf基于属性的动画.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:local="clr-namespace:Wpf基于属性的动画"
        mc:Ignorable="d"
        Title="MainWindow" Height="" Width="">
    <Grid >
        <Grid.RowDefinitions>
            <RowDefinition/>
            <RowDefinition/>
        </Grid.RowDefinitions>
        <Ellipse Name="ellipse" Height="" Width=""  Fill="Aquamarine"/>
        <Button Grid.Row=""  Content="开启动画" Height="" Width=""  Click="ButtonBase_OnClick" />
    </Grid>
</Window>

C#：

using System;
using System.Windows;
using System.Windows.Media.Animation;
using System.Windows.Shapes;

namespace Wpf基于属性的动画
{
    /// <summary>
    /// MainWindow.xaml 的交互逻辑
    /// </summary>
    public partial class MainWindow : Window
    {
        public MainWindow()
        {
            InitializeComponent();
        }

        private void ButtonBase_OnClick(object sender, RoutedEventArgs e)
        {
            DoubleAnimation doubleAnimation=new DoubleAnimation();
            doubleAnimation.From = ;
            doubleAnimation.To = ;
            doubleAnimation.Duration = TimeSpan.FromMilliseconds();
            doubleAnimation.FillBehavior = FillBehavior.Stop;
            ellipse.BeginAnimation(Ellipse.WidthProperty,doubleAnimation);
            DoubleAnimation doubleAnimation1 = new DoubleAnimation();
            doubleAnimation1.From = ;
            doubleAnimation1.To = ;
            doubleAnimation1.Duration = TimeSpan.FromMilliseconds();
            doubleAnimation1.FillBehavior = FillBehavior.Stop;
            ellipse.BeginAnimation(Ellipse.HeightProperty, doubleAnimation);
        }
    }
}