WPF-绕圈进度条（一）

<UserControl x:Class="ProgressBarControl" 
             xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"  
             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"  
             xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"   
             xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
             mc:Ignorable="d" d:DesignHeight="200" d:DesignWidth="300"
             Background="Transparent" Loaded="ProgressBarControl_OnLoaded">

    <Grid>
        <Grid.Resources>
            <Style TargetType="Ellipse">
                <Setter Property="Height" Value="{Binding EclipseSize}"></Setter>
                <Setter Property="Width" Value="{Binding EclipseSize}"></Setter>
                <Setter Property="Stretch" Value="Fill"></Setter>
                <!--设置圆的颜色-->
                <Setter Property="Fill" Value="White"></Setter>
            </Style>
        </Grid.Resources>
        <StackPanel   HorizontalAlignment="Center"  
            VerticalAlignment="Center">
            <Viewbox Width="{Binding ViewBoxSize}" Height="{Binding ViewBoxSize}"  
            HorizontalAlignment="Center"  
            VerticalAlignment="Center">
                <Grid x:Name="LayoutRoot"   
                Background="Transparent"  
                HorizontalAlignment="Center"  
                VerticalAlignment="Center">
                    <!--此处有canvas的加载和卸载事件-->
                    <Canvas x:Name="ProgressBarCanvas" RenderTransformOrigin="0.5,0.5"  
                    HorizontalAlignment="Center"  
                    VerticalAlignment="Center" Width="{Binding CanvasSize}"  
                    Height="{Binding CanvasSize}" Loaded="HandleLoaded"  
                    Unloaded="HandleUnloaded"  >
                        <!--画圆-->                        
                        <Canvas.RenderTransform>
                            <RotateTransform x:Name="SpinnerRotate" Angle="0" />
                        </Canvas.RenderTransform>
                    </Canvas>
                </Grid>
            </Viewbox>
        </StackPanel>
    </Grid>
</UserControl>