思路：
1.创建一个画布，长宽100*100；
<Canvas Width="100" Height="100">
2.画布上创建一个圆，直径25，位于正上方中间，底色浅灰；
<Style TargetType="Ellipse"><Setter Property="Width" Value="25"/><Setter Property="Height" Value="25"/><Setter Property="Fill" Value="LightGray"/><Setter Property="Canvas.Left" Value="37.5"/><Setter Property="Canvas.Top" Value="0"/><Setter Property="RenderTransformOrigin" Value="0.5,2"/></Style>
3.以上圆的0.5，2为圆心进行角度旋转，旋转7次，角度为45*N，得到共8个一模一样的圆；
1 <Ellipse/> 2 <Ellipse> 3 <Ellipse.RenderTransform> 4 <RotateTransform Angle="45"/> 5 </Ellipse.RenderTransform> 6 </Ellipse> 7 <Ellipse> 8 <Ellipse.RenderTransform> 9 <RotateTransform Angle="90"/> 10 </Ellipse.RenderTransform> 11 </Ellipse> 12 <Ellipse> 13 <Ellipse.RenderTransform> 14 <RotateTransform Angle="135"/> 15 </Ellipse.RenderTransform> 16 </Ellipse> 17 <Ellipse> 18 <Ellipse.RenderTransform> 19 <RotateTransform Angle="180"/> 20 </Ellipse.RenderTransform> 21 </Ellipse> 22 <Ellipse> 23 <Ellipse.RenderTransform> 24 <RotateTransform Angle="225"/> 25 </Ellipse.RenderTransform> 26 </Ellipse> 27 <Ellipse> 28 <Ellipse.RenderTransform> 29 <RotateTransform Angle="270"/> 30 </Ellipse.RenderTransform> 31 </Ellipse> 32 <Ellipse> 33 <Ellipse.RenderTransform> 34 <RotateTransform Angle="315"/> 35 </Ellipse.RenderTransform> 36 </Ellipse>
4.再按上述方法分别创建4个圆，旋转至上图红线中4处，底色黑色，设置不同的不透明度Opacity；
1 <Ellipse x:Name="ell1" Fill="Black" Opacity="0.2"> 2 <Ellipse.RenderTransform> 3 <RotateTransform Angle="0"/> 4 </Ellipse.RenderTransform> 5 </Ellipse> 6 <Ellipse x:Name="ell2" Fill="Black" Opacity="0.4"> 7 <Ellipse.RenderTransform> 8 <RotateTransform Angle="45"/> 9 </Ellipse.RenderTransform> 10 </Ellipse> 11 <Ellipse x:Name="ell3" Fill="Black" Opacity="0.6"> 12 <Ellipse.RenderTransform> 13 <RotateTransform Angle="90"/> 14 </Ellipse.RenderTransform> 15 </Ellipse> 16 <Ellipse x:Name="ell4" Fill="Black" Opacity="0.8"> 17 <Ellipse.RenderTransform> 18 <RotateTransform Angle="135"/> 19 </Ellipse.RenderTransform> 20 </Ellipse>
5.为画布Canvas增加Load动画，不停地更改上述4个圆的角度，实现旋转的视觉效果，中间写进度或者提示文字均可；
<Canvas.Triggers><EventTrigger RoutedEvent="Loaded"><BeginStoryboard><Storyboard RepeatBehavior="Forever"><DoubleAnimationUsingKeyFrames Storyboard.TargetName="ell1"Storyboard.TargetProperty="(UIElement.RenderTransform).(RotateTransform.Angle)"><DiscreteDoubleKeyFrame KeyTime="0:0:0.1" Value="45"/><DiscreteDoubleKeyFrame KeyTime="0:0:0.2" Value="90"/><DiscreteDoubleKeyFrame KeyTime="0:0:0.3" Value="135"/><DiscreteDoubleKeyFrame KeyTime="0:0:0.4" Value="180"/><DiscreteDoubleKeyFrame KeyTime="0:0:0.5" Value="225"/><DiscreteDoubleKeyFrame KeyTime="0:0:0.6" Value="270"/><DiscreteDoubleKeyFrame KeyTime="0:0:0.7" Value="315"/></DoubleAnimationUsingKeyFrames></Storyboard></BeginStoryboard>//另三个不再赘述</EventTrigger></Canvas.Triggers>
6.Canvas放在窗体中心平时隐藏需要时调出 或 以窗口形式弹出均可；
<load:LoadingWindow x:Name="loadingWD" Visibility="Hidden"/>
需要时调出
loadingWD.Visibility = flag ? Visibility.Visible : Visibility.Hidden;
