Double Click a ListBox item to open a browser

You can add a style to ListBox.ItemContainerStyle, and add an EventSetter there:

<ListBox>    ....    <ListBox.ItemContainerStyle>        <Style TargetType="{x:Type ListBoxItem}" BasedOn="{StaticResource {x:Type ListBoxItem}}">            <EventSetter Event="MouseDoubleClick" Handler="ListBoxItem_MouseDoubleClick"/>        </Style>    </ListBox.ItemContainerStyle></ListBox>

ListBoxItem_MouseDoubleClick is a method in your code behind with the correct signature for MouseDoubleClick.

I wanted to solve this without needing to handle the listBoxItem double click event in the code-behind, and I didn't want to have to override the listBoxItem style (or define the style to override in the first place). I wanted to just fire a command when the listBox was doubleclicked.

I created an attached property like so (the code is very specific, but you can generalise it as required):

public class ControlItemDoubleClick : DependencyObject {public ControlItemDoubleClick(){}public static readonly DependencyProperty ItemsDoubleClickProperty =    DependencyProperty.RegisterAttached("ItemsDoubleClick",    typeof(bool), typeof(Binding));public static void SetItemsDoubleClick(ItemsControl element, bool value){    element.SetValue(ItemsDoubleClickProperty, value);    if (value)    {        element.PreviewMouseDoubleClick += new MouseButtonEventHandler(element_PreviewMouseDoubleClick);    }}static void element_PreviewMouseDoubleClick(object sender, MouseButtonEventArgs e){    ItemsControl control = sender as ItemsControl;    foreach (InputBinding b in control.InputBindings)    {        if (!(b is MouseBinding))        {            continue;        }        if (b.Gesture != null            && b.Gesture is MouseGesture            && ((MouseGesture)b.Gesture).MouseAction == MouseAction.LeftDoubleClick            && b.Command.CanExecute(null))        {            b.Command.Execute(null);            e.Handled = true;        }    }}public static bool GetItemsDoubleClick(ItemsControl element){    return (bool)element.GetValue(ItemsDoubleClickProperty);}

}

I then declare my ListBox with the attached property and my target command:

<ListBox ItemsSource="{Binding SomeItems}"     myStuff:ControlItemDoubleClick.ItemsDoubleClick="true"><ListBox.InputBindings>    <MouseBinding MouseAction="LeftDoubleClick" Command="MyCommand"/></ListBox.InputBindings></ListBox>

Hope this helps.

I have updated AndrewS solution in order to solve the issue with firing executing the command if double click anywhere in the list box:

public class ControlDoubleClick : DependencyObject{    public static readonly DependencyProperty CommandProperty =        DependencyProperty.RegisterAttached("Command", typeof(ICommand), typeof(ControlDoubleClick), new PropertyMetadata(OnChangedCommand));    public static ICommand GetCommand(Control target)    {        return (ICommand)target.GetValue(CommandProperty);    }    public static void SetCommand(Control target, ICommand value)    {        target.SetValue(CommandProperty, value);    }    private static void OnChangedCommand(DependencyObject d, DependencyPropertyChangedEventArgs e)    {        Control control = d as Control;        control.PreviewMouseDoubleClick += new MouseButtonEventHandler(Element_PreviewMouseDoubleClick);    }    private static void Element_PreviewMouseDoubleClick(object sender, MouseButtonEventArgs e)    {        Control control = sender as Control;        ICommand command = GetCommand(control);        if (command.CanExecute(null))        {            command.Execute(null);            e.Handled = true;        }    }}

And in the XAML the declaration for the ListBox is:

<ListBox ItemsSource="{Binding MyItemsSource, Mode=OneWay}">                          <ListBox.ItemContainerStyle>                    <Style>                                                    <Setter Property="behaviours:ControlDoubleClick.Command" Value="{Binding DataContext.MyCommand,                                    RelativeSource={RelativeSource FindAncestor,                                     AncestorType={x:Type UserControl}}}"/>                     </Style>       </ListBox.ItemContainerStyle></ListBox>