add GotoTop

HandyControlDemo/UserControl/Controls/GotoTopDemoCtl.xaml

@@ -0,0 +1,19 @@
+<UserControl x:Class="HandyControlDemo.UserControl.GotoTopDemoCtl"
+             xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
+             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
+             xmlns:controls="clr-namespace:HandyControl.Controls;assembly=HandyControl"
+             Background="{DynamicResource RegionBrush}">
+    <Grid Width="500" Height="400">
+        <controls:ScrollViewer Name="ScrollViewerDemo" IsEnableInertia="True" Margin="0,10,0,0">
+            <Border Height="2000" Margin="8,0">
+                <Border.Background>
+                    <LinearGradientBrush EndPoint="0.5,1" StartPoint="0.5,0">
+                        <GradientStop Color="White" Offset="0"/>
+                        <GradientStop Color="Black" Offset="1"/>
+                    </LinearGradientBrush>
+                </Border.Background>
+            </Border>
+        </controls:ScrollViewer>
+        <controls:GotoTop Animated="True" AutoHiding="True" AnimationTime="500" Target="{Binding ElementName=ScrollViewerDemo}" HorizontalAlignment="Right" VerticalAlignment="Bottom" Margin="0,0,20,20"/>
+    </Grid>
+</UserControl>

HandyControlDemo/UserControl/Controls/GotoTopDemoCtl.xaml.cs

@@ -0,0 +1,10 @@
+namespace HandyControlDemo.UserControl
+{
+    public partial class GotoTopDemoCtl
+    {
+        public GotoTopDemoCtl()
+        {
+            InitializeComponent();
+        }
+    }
+}