值得注意的IsHitTestVisible

   <Grid>
        <Grid>
            <Grid.RowDefinitions>
                <RowDefinition Height="70" />
                <RowDefinition />
                <RowDefinition Height="50" />
            </Grid.RowDefinitions>
            <Border Background="Red">
                <Label Content="logo" Foreground="White" />
            </Border>
            <Grid Grid.Row="1" Background="#AAAFAF">
                <StackPanel
                    HorizontalAlignment="Center"
                    VerticalAlignment="Center"
                    Button.Click="StackPanel_Click">
                    <Button
                        Width="132"
                        Height="32"
                        Margin="10"
                        Content="金闪闪" />
                    <Button
                        Width="132"
                        Height="32"
                        Margin="10"
                        Content="小圆" />
                </StackPanel>
                <Label
                    Width="100"
                    Height="100"
                    Margin="76,29,266,171"
                    Background="Green"
                    Content="我不透明"
                    Foreground="Blue" />
                <Label
                    Width="100"
                    Height="40"
                    Margin="112,40,230,220"
                    Background="Red"
                    Content="我不透明"
                    Foreground="Blue" />
            </Grid>
            <Border Grid.Row="2" Background="#555F5F">
                <Label Content="状态栏" Foreground="White" />
            </Border>
        </Grid>
        <Image
            Name="img"
            Width="0"
            Height="0"
            HorizontalAlignment="Center"
            VerticalAlignment="Center"
            IsHitTestVisible="False"
            Opacity=".8"
            Source="/Image/jinshanshan.png"
            Stretch="Fill" />
    </Grid>

  private void StackPanel_Click(object sender, RoutedEventArgs e)
        {
            Button btn = (Button)e.OriginalSource;
            string content = btn.Content.ToString();
            if (content == "金闪闪")
            {
                img.Source = new BitmapImage(new Uri(@"/Image/jinshanshan.png", UriKind.Relative));
            }
            if (content == "小圆")
            {
                img.Source = new BitmapImage(new Uri(@"/Image/jinshanshan.png", UriKind.Relative));
            }

            DoubleAnimation daX = new DoubleAnimation();
            daX.From = 0;
            daX.To = 400;
            daX.FillBehavior = FillBehavior.HoldEnd;
            Storyboard.SetTarget(daX, img);
            Storyboard.SetTargetProperty(daX, new PropertyPath(Image.WidthProperty));
            DoubleAnimation daY = new DoubleAnimation();
            daY.From = 0;
            daY.To = 400;
            daY.FillBehavior = FillBehavior.HoldEnd;
            Storyboard.SetTarget(daY, img);
            Storyboard.SetTargetProperty(daY, new PropertyPath(Image.HeightProperty));
            DoubleAnimation daOp = new DoubleAnimation();
            daOp.From = 1;
            daOp.To = 1;
            daOp.FillBehavior = FillBehavior.HoldEnd;
            Storyboard.SetTarget(daOp, img);
            Storyboard.SetTargetProperty(daOp, new PropertyPath(Image.OpacityProperty));

            Storyboard sb = new Storyboard();
            sb.Children.Add(daX);
            sb.Children.Add(daY);
            sb.Children.Add(daOp);
            sb.Begin();
        }