How to Open ComboBox List on KeyPress F5 in WPF ?

I have a WPF ComboBox in my XAML file. And I want to Force the ComboBox to show its list items when I press F5. For this requirement, we have a property ‘IsDropDownOpen’ of ComboBox, which I set to True.

cmbCountry.IsDropDownOpen = true;

<Window x:Class="ComboBoxDemo.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        Title="ComboBoxF5Demo" Height="350" Width="425" Background="#98dafc">
    <StackPanel>
        <TextBlock Text="Press F5 to Open DropDown List" FontSize="20" Margin="20" HorizontalAlignment="Center" />
        <ComboBox x:Name="cmbCountry" HorizontalAlignment="Left" IsEditable="True" Margin="110,30,0,0" 
        	SelectedIndex="0" VerticalAlignment="Top" Height="40" FontSize="20" Width="200">
            <ComboBoxItem  Content="--Select--" />
            <ComboBoxItem Content="India" />
            <ComboBoxItem Content="US" />
            <ComboBoxItem Content="France" />
            <ComboBoxItem Content="SwitzerLand" />
        </ComboBox>
    </StackPanel>
</Window>

using System.Windows;
using System.Windows.Input;
 
 
namespace ComboBoxDemo
{
    /// <summary>
    /// Interaction logic for MainWindow.xaml
    /// </summary>
    public partial class MainWindow : Window
    {
        public MainWindow()
        {
            InitializeComponent();
            cmbCountry.KeyDown += cmbCountry_KeyDown;
        }
 
        /// <summary>
        ///  Occurs when a key is pressed while focus is on this element.
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        void cmbCountry_KeyDown(object sender, KeyEventArgs e)
        {
            if (e.Key == Key.F5)
                cmbCountry.IsDropDownOpen = true;
        }
    }
}