WPF

private static bool IsEmailAllowed(string text)
        {
            Regex regEMail = new Regex(@"^[a-zA-Z][\w\.-]{2,28}[a-zA-Z0-9]@[a-zA-Z0-9][\w\.-]*[a-zA-Z0-9]\.[a-zA-Z][a-zA-Z\.]*[a-zA-Z]$");
            return !regEMail.IsMatch(text);
        }

        private void txtEmail_PreviewTextInput(object sender, TextCompositionEventArgs e)
        {
            e.Handled = !IsEmailAllowed(e.Text);            
        } 

private void txtEmail_Validating(object sender, CancelEventArgs e)
        {
            System.Text.RegularExpressions.Regex rEMail = new System.Text.RegularExpressions.Regex(@"^[a-zA-Z][\w\.-]{2,28}[a-zA-Z0-9]@[a-zA-Z0-9][\w\.-]*[a-zA-Z0-9]\.[a-zA-Z][a-zA-Z\.]*[a-zA-Z]$");
            if (txtEmail.Text.Length > 0)
            {
                if (!rEMail.IsMatch(txtEmail.Text))
                {
                    MessageBox.Show("E-Mail expected", "Error", MessageBoxButtons.OK, MessageBoxIcon.Error);
                    txtEmail.SelectAll();
                    e.Cancel = true;
                }
            }
        }

<ListBox Grid.Row="1" Grid.Column="2" x:Name="lbDirectiveList" ItemsSource="{Binding}" SelectionChanged="lbDirectiveList_SelectionChanged" MaxHeight="200" SelectionMode="Single" ScrollViewer.VerticalScrollBarVisibility="Auto">
                            <ListBox.ItemTemplate>
                                <DataTemplate>
                                    <Grid Margin="4">
                                        <Grid.ColumnDefinitions>
                                            <ColumnDefinition Width="Auto" />
                                            <ColumnDefinition Width="25" />
                                            <ColumnDefinition Width="*" />
                                        </Grid.ColumnDefinitions>

                                        <TextBlock Text="{Binding Path=DirectiveName, Mode=TwoWay}" Grid.Column="0" FontWeight="Bold" MinWidth="200"/>
                                        <TextBlock Text=" - " Grid.Column="1"/>
                                        <TextBlock Grid.Column="2" Text="{Binding Path=DirectiveDescription, Mode=TwoWay}" />
                                    </Grid>
                                </DataTemplate>
                            </ListBox.ItemTemplate>
                        </ListBox>

<Window x:Class="Abtech.Spares.UI.Views.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:telerik="http://schemas.telerik.com/2008/xaml/presentation"
        xmlns:local="clr-namespace:Abtech.Spares.DataModel.Models;assembly=Abtech.Spares.DataModel.Models"
        Title="My App" 
        Height="600" 
        Width="800">

<Window.Resources>

    <DataTemplate x:Key="Project" DataType="{x:Type local:ProjectModel}">
        <StackPanel Orientation="Horizontal">
            <Image Source="/Abtech.Spares.UI;component/Media/Graphics/Sidebar/project_16x16.png" Margin="0,0,2,0"></Image>
            <TextBlock Text="{Binding ProjectName}" />
        </StackPanel>
    </DataTemplate>

</Window.Resources>