Disabling Keyboard Navigation in .NET MAUI to Prevent Random Button Clicks with Barcode Scanner

[LennartKleymann]

Hello everyone,

I'm working on a .NET MAUI application that uses a hardware barcode scanner. After each barcode scan, the scanner sends an Enter key press. However, this causes an issue in the app because random buttons sometimes get focused and clicked after a scan due to keyboard navigation.

I've set up SharpHook to intercept the barcode inputs and check for the timing between keystrokes to distinguish actual scans from manual input. While this approach works for handling the barcode data itself, the problem persists with the automatic Enter key triggering unwanted button clicks.

Here’s what I’m looking for: I’d like to disable the default keyboard navigation so that the Enter key doesn’t activate a button or change focus within my app. Is there a way to prevent keyboard focus from moving around or to disable keyboard navigation entirely in .NET MAUI?

Any guidance on how to achieve this would be greatly appreciated!

I am only using windows as plattform.

Thanks in advance!

[Stedy59]

Most likely you are using the scanner in "keyboard" mode. What is the maker/model of the barcode hardware? You should be able to use the manufacturers sdk or simply modify the scanner to not send a carriage return with the data. Let me know....

[stephenquan]

If you know that the barcode scanner is sending an Enter key, you can incorporate that in your Barcode detection with the use of an Entry field as follows:

<Entry x:Name="barcodeEntry" Completed="barcodeEntry_Completed" IsEnabled="True" Opacity="0" Unfocused="barcodeEntry_Unfocused" />

The corresponding code-behind will be:

private async void barcodeEntry_Unfocused(object sender, FocusEventArgs e)
{
    Entry entry = (Entry)sender;
    if (IsEnabled)
    {
        await Task.Delay(50);
        entry.Focus();
    }
}

private void barcodeEntry_Completed(object sender, EventArgs e)
{
    Entry entry = (Entry)sender;
    Trace.WriteLine($"Barcode scanned: {entry.Text}");
}

This means, whilst you're expecting barcode input, navigation is neutralized, and the Enter will be used to complete the barcode handler.

I took liberties in hiding the Entry component with Opacity="0" but, whether you need to follow through or adapt this idea is really up to you.