Attempting to execute method using KeyBinding - wpf

Question

I'm trying to execute a method when the user presses ctrl + Tab. If there is more than one window (App.Current.Windows >1), then CanExecute should be true, otherwise false.
All posts I read so far suggest I need to write a subclass for ICommand and a ViewModel which is basically the "link" between the UI and tge custom command. I've read some examples
of how to create bindings
and because I didn't get this I tried to
learn more about MVVM
but I'm afraid I'm still feeling clueless.
What would an example checking for more than one window open and executing a method SomeMethod if CanExecute was true look like? Where would I place what? I'm sorry, but I searched and tried all day - and still feel clueless.
Any examples or pointers to good explanations?

Answer 1

Here is how you can do it
in Xaml:
<Window x:Class="Test.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
mc:Ignorable="d"
Title="MainWindow" Height="450" Width="800">
<Window.Resources>
<RoutedUICommand x:Key="ExecuteCommand" Text="ExecuteCommand" />
</Window.Resources>
<Window.InputBindings>
<KeyBinding Key="Tab" Modifiers="Ctrl" Command="{StaticResource ExecuteCommand}" />
</Window.InputBindings>
<Window.CommandBindings>
<CommandBinding Command="{StaticResource ExecuteCommand}" CanExecute="ExecuteCommand_CanExecute" Executed="ExecuteCommand_Executed" />
</Window.CommandBindings>
<Grid>
</Grid>
</Window>
In Code Behind:
private void ExecuteCommand_CanExecute(object sender, CanExecuteRoutedEventArgs e)
{
e.CanExecute = App.Current.Windows.Count > 1;
}
private void ExecuteCommand_Executed(object sender, ExecutedRoutedEventArgs e)
{
MessageBox.Show("Hello");
}
Hope it helps.

Answer 2

I am getting the feeling that you are new to WPF and MVVM, Although it's recommended, you don't have to use MVVM with WPF. You can do the same thing by event handlers.
Here is something you might want to try:
public partial class MainWindow : Window
{
public MainWindow()
{
InitializeComponent();
KeyUp += MainWindow_KeyUp;
}
private void MainWindow_KeyUp(object sender, KeyEventArgs e)
{
if (e.Key == Key.Tab && (Keyboard.IsKeyDown(Key.LeftCtrl) || Keyboard.IsKeyDown(Key.RightCtrl)))
{
MessageBox.Show(App.Current.Windows.Count.ToString());
}
}
}