WinUI3 : How to catch CTRL + A key press in WinUI3 TextBox

Question

Hi,

Im working on WinUI3 desktop application in CPP. I wanted to Catch CTRL + A press on WinUI3 TextBox. I checked online and found CoreWindow.GetKeyState(VirtualKey), but this will not work on Desktop applciation.

I used TextBox.KeyDown with GetKeyState(VK_CONTROL) to get CTRL + A, but it did not work. but TextBox.KeyUp with GetKeyState(VK_CONTROL) worked. Why is that so? Is this the right way to get CTRL + A key event?

Edit : Code snippet

    `textBox.KeyDown([textBox](auto const& sender, winrt::Microsoft::UI::Xaml::Input::KeyRoutedEventArgs const& args)`
            {

                // Get the virtual key

                if (args.Key() == winrt::Windows::System::VirtualKey::A )

                {

                    if (GetKeyState(VK_CONTROL) & 0x8000) // 0x8000 indicates the key is down

                    {

                        int check = 0; // This Line was not hit, When CTRL + A was pressed

                    }

                    // Mark event as handled to prevent default behavior

                    args.Handled(true);

                }

            });

         textBox.KeyUp([textBox](auto const& sender, winrt::Microsoft::UI::Xaml::Input::KeyRoutedEventArgs const& args)

             {

                 // Get the virtual key

                 if (args.Key() == winrt::Windows::System::VirtualKey::A)

                 {

                     if (GetKeyState(VK_CONTROL) & 0x8000) // 0x8000 indicates the key is down

                     {

                         int a = 0; //  This Line was hit, When CTRL + A was pressed 

                     }

                     // Mark event as handled to prevent default behavior

                     args.Handled(true);

                 }

             });

Answer 1

Hi

Welcome to Microsoft Q&A!

I used TextBox.KeyDown with GetKeyState(VK_CONTROL), but it did not work. but TextBox.KeyUp with GetKeyState(VK_CONTROL) worked. Why is that so?

The shortcut of the system already contains CTRL + A, so when CTRL + A is pressed, it will be intercepted by the system.

If you want to catch CTRL + A key press, you need to override this shortcut manually via KeyboardAccelerators

            <TextBox.KeyboardAccelerators>
                <KeyboardAccelerator Key="A" Modifiers="Control" Invoked="OnCtrlCInvoked"/>
            </TextBox.KeyboardAccelerators>

    private void OnCtrlCInvoked(KeyboardAccelerator sender, KeyboardAcceleratorInvokedEventArgs args)
    {
        if (args.KeyboardAccelerator.Key == VirtualKey.A && args.KeyboardAccelerator.Modifiers == VirtualKeyModifiers.Control)
        {
            System.Diagnostics.Debug.WriteLine("Ctrl+A Pressed");
            args.Handled = true;
        }
    }

For more details you could refer to the Doc: WinUI 3 APIs (Windows App SDK)

Thank you

Jeanine