A simple WPF fading popup control

Steps:

1.) Create a WPF Project in Visual Studio.  I named mine FadingPopup. (Note: You can use 3.5 or 4.0, but you will need to use 4.0 if you want to take advantage of the animation EasingFunctions.)
2.) Add a User Control with the following code:

FadingPopupControl.xaml

<UserControl x:Class="FadingPopup.FadingPopupControl"
             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" BorderThickness="0" Margin="0">
    <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="0:0:1.5">
                <DoubleAnimation.EasingFunction>
                    <ExponentialEase Exponent="10" EasingMode="EaseIn" />
                </DoubleAnimation.EasingFunction>
            </DoubleAnimation>
        </Storyboard>
    </UserControl.Resources>
    <Popup Name="popup" Placement="Center" PopupAnimation="Fade" AllowsTransparency="True">
        <Grid Background="Transparent">
            <Grid Name="popupBackground" Background="Black" Grid.Column="0" Grid.Row="0" />
            <Label Name="popupLabel" DockPanel.Dock="Bottom" HorizontalAlignment="Center" Foreground="White" VerticalAlignment="Center" Background="Transparent" Grid.Column="0" Grid.Row="0"/>
        </Grid>
    </Popup>
</UserControl>

FadingPopupControl.xaml.cs

using System;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Media.Animation;

namespace FadingPopup
{
    public partial class FadingPopupControl : UserControl
    {
        Window ParentWindow { get; set; }
        public FadingPopupControl()
        {
            InitializeComponent();
        }

        protected override void OnInitialized(EventArgs e)
        {
            base.OnInitialized(e);            
        }

        public void ShowDialogBox(Window parentWindow, string message)
        {
            ParentWindow = parentWindow;
            popupLabel.Content = message;
            Storyboard StatusFader = (Storyboard)Resources["StatusFader"];
            ParentWindow.IsEnabled = false;
            FrameworkElement root = (FrameworkElement)ParentWindow.Content;
            this.Height = root.ActualHeight;
            this.Width = root.ActualWidth;
            //TODO: Determine why there is 1 pixel extra whitespace.
            //Tried playing with Margins and Alignment to no avail.
            popup.Height = root.ActualHeight + 1; 
            popup.Width = root.ActualWidth + 1;            
            popup.IsOpen = true;
            StatusFader.Begin(popupBackground);
        }

        void StatusFader_Completed(object sender, EventArgs e)
        {
            popup.IsOpen = false;
            ParentWindow.IsEnabled = true;            
        }
    }
}

 

3.) In the MainWindow.xaml, add a Button with a PreviewMouseLeftButtonDown event handler.
4.) Add a local reference and then your popup control.
5.) In your button event handler, initiate the popup.

MainWindow.xaml

<Window x:Class="FadingPopup.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:local="clr-namespace:FadingPopup"
        xmlns:controls="clr-namespace:System.Windows.Controls;assembly=PresentationFramework"
        Title="MainWindow" Height="350" Width="525">
    <Grid>
        <Button x:Name="Test1" Height="40" Width="80" Content="Test1" Grid.Column="0" AllowDrop="False" PreviewMouseLeftButtonDown="Test1_PreviewMouseLeftButtonDown" />
        <local:FadingPopupControl x:Name="popup" />
    </Grid>
</Window>

MainWindow.xaml.cs

using System.Windows;
using System.Windows.Input;

namespace FadingPopup
{
    public partial class MainWindow : Window
    {
        public MainWindow()
        {
            InitializeComponent();
        }

        private void Test1_PreviewMouseLeftButtonDown(object sender, MouseButtonEventArgs e)
        {
            popup.ShowDialogBox(Test1, "The is a sample message...");
        }
    }
}

Screenshots

This fades out in 1.2 seconds