Question

I have a textbox which has keydown event when entered key is “return” I have a barcode reader who read text into it but it is not writing more than one key i.e. only one letter is written lets say “a” and if i write second letter “a” is overwritten to become “b” but does not become “ab”. Does anyone know what is cause of this ?

private void barcodetexbox_KeyDown(object sender, KeyEventArgs e)
{
    if (scannedString.Text != "" && e.Key==Key.Return)
    {
        //do something
    }
}

and in “MainWindow.xaml”

<TextBox x:Name="scannedString" HorizontalAlignment="Left" Height="50" 
    Margin="468,164,0,0" TextWrapping="Wrap" VerticalAlignment="Top" Width="450"
    FontSize="24" Focusable="True" Padding="0,6,0,0" 
    KeyDown="barcodetexbox_KeyDown" />

Answer 1

The KeyDown event is designed to let you know which keys are down at one moment, and your barcode reader seems to simulate a keyboard, so you’ll need to concatenate the characters it sends

in your Key_Down event, you would have to do something like that:

this.scannedString += e.Key;

and when you see return:

barcodeTextBox.Text = this.scannedString;