Is Key.CapsLock Toggled
<Window x:Class="WpfApplication1.Window1" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" Title="WPF" Height="170" Width="200"> <StackPanel HorizontalAlignment="Center"> <UniformGrid Columns="2"> <UniformGrid.Resources> <Style TargetType="{x:Type CheckBox}"> <Setter Property="IsHitTestVisible" Value="False" /> <Setter Property="Margin" Value="5" /> </Style> </UniformGrid.Resources> </UniformGrid> <Button Content="Check Keyboard" Margin="10" Click="Button_Click"/> </StackPanel> </Window> //File:Window.xaml.cs using System; using System.Windows; using System.Windows.Input; namespace WpfApplication1 { public partial class Window1 : Window { public Window1() { InitializeComponent(); CheckKeyboardState(); } private void Button_Click(object sender, RoutedEventArgs e) { CheckKeyboardState(); } private void CheckKeyboardState() { Console.WriteLine(Keyboard.IsKeyToggled(Key.CapsLock)); } } }