用wpf写一个load等待的漂亮的界面

以下是一个简单的WPF等待界面示例：

<Window x:Class="WpfLoadingDemo.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        Title="WPF Loading Demo" Height="350" Width="525">
    <Grid>
        <Grid.RowDefinitions>
            <RowDefinition Height="Auto"/>
            <RowDefinition Height="Auto"/>
            <RowDefinition Height="Auto"/>
            <RowDefinition Height="Auto"/>
        </Grid.RowDefinitions>
        <Grid.ColumnDefinitions>
            <ColumnDefinition Width="Auto"/>
            <ColumnDefinition Width="Auto"/>
            <ColumnDefinition Width="Auto"/>
        </Grid.ColumnDefinitions>
        <TextBlock Text="Loading..." Grid.Row="0" Grid.Column="1" HorizontalAlignment="Center" Margin="0,40,0,0"/>
        <Canvas Grid.Row="1" Grid.Column="1">
            <Ellipse Canvas.Left="0" Canvas.Top="0" Width="20" Height="20" Fill="#FF8C8C8C">
                <Ellipse.Triggers>
                    <EventTrigger RoutedEvent="Loaded">
                        <BeginStoryboard>
                            <Storyboard>
                                <DoubleAnimationUsingKeyFrames BeginTime="00:00:00"
                                                               Storyboard.TargetName="ellipse"
                                                               Storyboard.TargetProperty="(UIElement.RenderTransform).(TransformGroup.Children)[3].(RotateTransform.Angle)"
                                                               RepeatBehavior="Forever">
                                    <SplineDoubleKeyFrame KeyTime="0:0:0" Value="0"/>
                                    <SplineDoubleKeyFrame KeyTime="0:0:1" Value="360"/>
                                </DoubleAnimationUsingKeyFrames>
                            </Storyboard>
                        </BeginStoryboard>
                    </EventTrigger>
                </Ellipse.Triggers>
                <Ellipse.RenderTransform>
                    <TransformGroup>
                        <ScaleTransform/>
                        <SkewTransform/>
                        <RotateTransform/>
                        <TranslateTransform/>
                    </TransformGroup>
                </Ellipse.RenderTransform>
            </Ellipse>
            <Ellipse x:Name="ellipse" Canvas.Left="0" Canvas.Top="0" Width="20" Height="20" StrokeThickness="5" Stroke="#FF26C6DA"
                     Fill="Transparent" >
                <Ellipse.Triggers>
                    <EventTrigger RoutedEvent="Loaded">
                        <BeginStoryboard>
                            <Storyboard>
                                <DoubleAnimationUsingKeyFrames BeginTime="00:00:00"
                                                               Storyboard.TargetName="ellipse"
                                                               Storyboard.TargetProperty="(UIElement.RenderTransform).(TransformGroup.Children)[3].(RotateTransform.Angle)"
                                                               RepeatBehavior="Forever">
                                    <SplineDoubleKeyFrame KeyTime="0:0:0" Value="0"/>
                                    <SplineDoubleKeyFrame KeyTime="0:0:1" Value="360"/>
                                </DoubleAnimationUsingKeyFrames>
                            </Storyboard>
                        </BeginStoryboard>
                    </EventTrigger>
                </Ellipse.Triggers>
                <Ellipse.RenderTransform>
                    <TransformGroup>
                        <ScaleTransform/>
                        <SkewTransform/>
                        <RotateTransform/>
                        <TranslateTransform/>
                    </TransformGroup>
                </Ellipse.RenderTransform>
            </Ellipse>
            <Ellipse Canvas.Left="0" Canvas.Top="0" Width="20" Height="20" StrokeThickness="5" Stroke="#FF26C6DA"
                     Fill="Transparent" >
                <Ellipse.Triggers>
                    <EventTrigger RoutedEvent="Loaded">
                        <BeginStoryboard>
                            <Storyboard>
                                <DoubleAnimationUsingKeyFrames BeginTime="00:00:00"
                                                               Storyboard.TargetName="ellipse"
                                                               Storyboard.TargetProperty="(UIElement.RenderTransform).(TransformGroup.Children)[3].(RotateTransform.Angle)"
                                                               RepeatBehavior="Forever">
                                    <SplineDoubleKeyFrame KeyTime="0:0:0" Value="0"/>
                                    <SplineDoubleKeyFrame KeyTime="0:0:1" Value="360"/>
                                </DoubleAnimationUsingKeyFrames>
                            </Storyboard>
                        </BeginStoryboard>
                    </EventTrigger>
                </Ellipse.Triggers>
                <Ellipse.RenderTransform>
                    <TransformGroup>
                        <ScaleTransform/>
                        <SkewTransform/>
                        <RotateTransform/>
                        <TranslateTransform/>
                    </TransformGroup>
                </Ellipse.RenderTransform>
            </Ellipse>
        </Canvas>
    </Grid>
</Window>

这个等待界面由三个重叠的圆组成，中心圆是灰色的，边缘两个圆是蓝色的。圆通过“旋转变换”动画旋转，以创建旋转动画效果。您可以自定义颜色和大小以创建自己的等待界面。