private void ShowAlert()
        {
            if (IsShowAlert &&
                AlertTitle.IsNotNullOrEmpty() &&
                AlertText.IsNotNullOrEmpty())
            {
                // Create a new BitmapImage
                BitmapImage bitmap = new BitmapImage();
                bitmap.BeginInit();
                bitmap.UriSource = new Uri("pack://application:,,,/Images/GSI_Cloud_256.ico");
                bitmap.EndInit();

                var image = new System.Windows.Controls.Image() { Source = bitmap };

                desktopAlertManager.ShowAlert(new DesktopAlertParameters
                {
                    Header = AlertTitle,
                    Content = AlertText,
                    Icon = image,
                    IconColumnWidth = 48,
                    IconMargin = new Thickness(10, 0, 20, 0),
                    ShowDuration = AlertShowDuration,
                    Command = new DelegateCommand(OnAlertCommandExecuted)
                });
            }
        }

        private void OnAlertCommandExecuted(object param)
        {
            IsShowTrayApp = true;
        }

<ResourceDictionary xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
                    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
                    xmlns:telerikNavigation="clr-namespace:Telerik.Windows.Controls;assembly=Telerik.Windows.Controls.Navigation">

    <SolidColorBrush x:Key="DesktopAlert_BorderBrush" Color="#FF848484"/>
    <LinearGradientBrush x:Key="DesktopAlert_Background" EndPoint="0.5,1" StartPoint="0.5,0">
        <GradientStop Color="Cornsilk" Offset="0"/>
        <GradientStop Color="#FFD4D4D4" Offset="1"/>
    </LinearGradientBrush>
    <SolidColorBrush x:Key="DesktopAlert_InnerBorderBrush" Color="#FFFFFFFF"/>
    <CornerRadius x:Key="DesktopAlert_CornerRadius">1</CornerRadius>
    <SolidColorBrush x:Key="DesktopAlert_ButtonIconStroke" Color="#FFFFFFFF"/>
    <LinearGradientBrush x:Key="DesktopAlert_ButtonIconFill" EndPoint="0.5,1" StartPoint="0.5,0">
        <GradientStop Color="#FF282828"/>
        <GradientStop Color="#FF7C7C7C" Offset="1"/>
    </LinearGradientBrush>

    <DataTemplate x:Key="RadDesktopAlertHeaderTemplate">
        <Grid 
            x:Name="Header" 
            Grid.Column="1" 
            Grid.Row="0" 
            VerticalAlignment="Top" 
            HorizontalAlignment="Stretch"
            Background="{StaticResource ContainerHeaderBackgroundBrush}">

            <StackPanel
                HorizontalAlignment="Left"
                Orientation="Horizontal">

                <Grid>
                    <Grid.ColumnDefinitions>
                        <ColumnDefinition Width="30" />
                        <ColumnDefinition Width="*" />
                    </Grid.ColumnDefinitions>

                    <Image 
                        RenderOptions.BitmapScalingMode="Fant"
                        Margin="5 0 5 0"
                        Source="/Images/GSI_Cloud_256.ico"/>

                    <Label
                        Grid.Column="1"
                        Foreground="White"
                        FontWeight="SemiBold"
                        FontSize="14"
                        VerticalContentAlignment="Center"
                        VerticalAlignment="Center"/>
                </Grid>
                
            </StackPanel>

            <StackPanel
                HorizontalAlignment="Right"
                Orientation="Horizontal">

                <Button Height="30" Width="30"  
	                x:Name="DesktopAlert_CloseButton" 
                    Content="🗙"
                    Background="Transparent"
                    BorderThickness="0"
                    Foreground="White"
                    FontSize="20"
                    Margin="0 -3 0 0"
                    FontWeight="Bold"
                    Command="{x:Static telerikNavigation:DesktopAlertCommands.Close}" />

            </StackPanel>

            <ContentPresenter 
                Content="{Binding}" 
                TextBlock.FontWeight="Bold" 
                Margin="0 0 0 0" 
                MinHeight="{Binding ActualHeight, ElementName=DesktopAlert_CloseButton}" Grid.RowSpan="2" VerticalAlignment="Top">

                <ContentPresenter.Resources>
                    <Style TargetType="{x:Type TextBlock}">
                        <Setter Property="TextWrapping" Value="Wrap"/>
                        <Setter Property="Foreground" Value="White" />
                        <Setter Property="VerticalAlignment" Value="Center" />
                        <Setter Property="HorizontalAlignment" Value="Left" />
                        <Setter Property="Margin" Value="30 0 0 0" />
                    </Style>
                </ContentPresenter.Resources>
            </ContentPresenter>

        </Grid>
    </DataTemplate>

    <ControlTemplate x:Key="RadDesktopAlertTemplate" TargetType="{x:Type telerikNavigation:RadDesktopAlert}">
        <Grid x:Name="LayoutRoot">
            <Border Background="White"
                    BorderThickness="{TemplateBinding BorderThickness}" 
                    CornerRadius="{StaticResource DesktopAlert_CornerRadius}">

                <Border BorderBrush="{StaticResource DesktopAlert_InnerBorderBrush}" BorderThickness="1">
                    <Grid>
                        <Grid.RowDefinitions>
                            <RowDefinition Height="Auto"/>
                            <RowDefinition Height="*"/>
                            <RowDefinition Height="26" />
                        </Grid.RowDefinitions>
                        
                        <ContentPresenter 
                            ContentTemplate="{TemplateBinding HeaderTemplate}" 
                            Grid.Column="1" 
                            Content="{TemplateBinding Header}" 
                            Grid.Row="0" VerticalAlignment="Top"/>

                        <ContentPresenter 
                            x:Name="Content" 
                            Cursor="Hand" 
                            Grid.Column="1" 
                            HorizontalAlignment="Center" 
                            Margin="0 7 0 0" Grid.Row="1" VerticalAlignment="Top">

                            <ContentPresenter.Resources>
                                <Style TargetType="{x:Type TextBlock}">
                                    <Setter Property="TextWrapping" Value="Wrap"/>
                                    <Setter Property="TextTrimming" Value="CharacterEllipsis"/>
                                    <Setter Property="HorizontalAlignment" Value="Center" />
                                    <Setter Property="FontSize" Value="14" />
                                </Style>
                            </ContentPresenter.Resources>
                        </ContentPresenter>

                        <Grid Grid.Row="2">
                            <Grid.ColumnDefinitions>
                                <ColumnDefinition Width="*" />
                                <ColumnDefinition Width="*" />
                                <ColumnDefinition Width="126" />
                            </Grid.ColumnDefinitions>

                            <Button
                                Style="{StaticResource ButtonStyle}"
                                Grid.Column="2"
                                Content="Open" 
                                Command="{Binding OnAlertCommandExecuted}"/>
                        </Grid>
                    </Grid>
                </Border>
            </Border>
        </Grid>
    </ControlTemplate>

    <Style TargetType="{x:Type telerikNavigation:RadDesktopAlert}">
        <Setter Property="Padding" Value="10 8"/>
        <Setter Property="Opacity" Value="0.9"/>
        <Setter Property="SnapsToDevicePixels" Value="True"/>
        <Setter Property="FontFamily" Value="Segoe UI"/>
        <Setter Property="FontSize" Value="14"/>
        <Setter Property="Background" Value="Transparent"/>
        <Setter Property="BorderBrush" Value="{StaticResource DesktopAlert_BorderBrush}"/>
        <Setter Property="BorderThickness" Value="1"/>
        <Setter Property="Width" Value="360"/>
        <Setter Property="Height" Value="130"/>
        <Setter Property="Template" Value="{StaticResource RadDesktopAlertTemplate}"/>
        <Setter Property="HeaderTemplate" Value="{StaticResource RadDesktopAlertHeaderTemplate}"/>
    </Style>
</ResourceDictionary>