How can i create callout for a popup in wpf.

<UserControl x:Class="WpfApplication1.UserControl1"
             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="104" d:DesignWidth="564">
    <UserControl.Resources>
        <Storyboard x:Name="StatusFader" x:Key="StatusFader"  Completed="StatusFader_Completed">
            <DoubleAnimation Storyboard.TargetName="popupBackground" Storyboard.TargetProperty="Opacity" From="0.7" To="0" BeginTime="0:0:0"  Duration="0:0:4.5">
                <!--<DoubleAnimation.EasingFunction>
                    <ExponentialEase Exponent="10" EasingMode="EaseIn" />
                </DoubleAnimation.EasingFunction>-->
            </DoubleAnimation>
        </Storyboard>
    </UserControl.Resources>
    <Grid Height="43" Width="289" AllowDrop="True" >
        <Grid.ColumnDefinitions>
            <ColumnDefinition Width="39*" />
            <ColumnDefinition Width="225*" />
        </Grid.ColumnDefinitions>
        <Popup Name="popup" Placement="Center" PopupAnimation="Fade" AllowsTransparency="True"  Grid.ColumnSpan="2" Height="100">
            <Border BorderBrush="CornflowerBlue"            
            BorderThickness="3,3,3,3"
            CornerRadius="10"
                    
            removed="Beige">
                <Grid removed="Transparent">
                    <Grid Name="popupBackground" removed="Beige" Grid.Column="0" Grid.Row="0" />
                    <Label  Name="popupLabel" DockPanel.Dock="Bottom" HorizontalAlignment="Center"   VerticalAlignment="Center" Background="Transparent" Grid.Column="0" Grid.Row="0"/>
                </Grid>
            </Border>
        </Popup>
    </Grid>
</UserControl>

/////.cs/////
  void StatusFader_Completed(object sender,EventArgs e) {
      popup.IsOpen = false;
    }
    public void ShowDialogBox(string message)
    {

      popupLabel.Content = message;
      Storyboard StatusFader = (Storyboard)Resources["StatusFader"];
      popup.IsOpen = true;
     StatusFader.Begin();
    }