CODEWITHSUNDEEP
uwp
kesrut
kesrut

Reputation: 682

C# UWP KeyDown event e.Handled strange behavier

I want to enable only certain keys in UWP TextBox element. But setting e.Handled = false not helps. All keys accepted.

Similar application in WPF works.

How to solve this problem?

XAML: 

 <Grid>
        <TextBox HorizontalAlignment="Left" Margin="251,166,0,0" VerticalAlignment="Top" KeyDown="TextKeyDown" Height="32" Width="579"/>
    </Grid>

C#

private void TextKeyDown(object sender, KeyRoutedEventArgs e)
        {
            if (System.Text.RegularExpressions.Regex.IsMatch(e.Key.ToString(), "[0-9]"))
            {
                e.Handled = false;
                System.Diagnostics.Debug.WriteLine("number");
            }
            else e.Handled = true;


}

Upvotes: 0

Views: 287

Answers (1)

Rob Caplan - MSFT
Rob Caplan - MSFT

Reputation: 21899

Input to the TextBox isn't coming directly through the Key events, and in many cases text input doesn't involves key events at all (think IMEs, auto-complete, on-screen-keyboards, ink input, speech recognition, etc.)

The TextChanging and TextChanged events will fire regardless of the origin of the text and so are better place to implement your filter.

There are pre-built filtering extensions in the Windows Community Toolkit that may suit you rather than rolling your own. Check out TextBoxMask and TextBoxRegex.

Upvotes: 1

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