How do I display the output from the serial port continuously after clicking the button once? Using WPF

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C#

WPF

I have a wired usb QR Scanner. Its very small. Task: I am trying to scan the qr code ( example it scans the serial no = 1025678 ). And different qr code with different qr numbers. So it scans the qr number and then displays the output in the textbox. I am using C#-WPF to code the software.

I would like to know how i can display the output continously by clicking the button once?.

What I have tried:

I have tried to open the port and its successful and then i have tried to display the output in the text box, but I have to click the serial code button everytime to display the qr number and I am finding out a way to display the output by clicking the button once, but i am not able to. I would like to know if someone could help me.

below is the code of what i have tried.

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Navigation;
using System.Windows.Shapes;
using System.IO.Ports;
using System.Threading;
using System.Windows.Threading;


namespace WpfApp3
{
    /// <summary>
    /// Interaktionslogik für MainWindow.xaml
    /// </summary>
    public partial class MainWindow : Window
    {
        SerialPort sp1 = new SerialPort();

        public MainWindow()
        {
            InitializeComponent();

        }
        private void ComboBox_SelectChanged(object sender, SelectionChangedEventArgs e)
        {

            var selectedcomboitem = sender as ComboBox;
            string name = selectedcomboitem.SelectedItem as string;
        }
        private void Button_Click(object sender, RoutedEventArgs e)
        {

            try
            {
                string portName = cboPort1.SelectedItem as string;
                sp1.PortName = portName;
                sp1.BaudRate = 9600;
                sp1.Open();
                statussq.Text = "Connected";
               
                  
                

            }
            catch (Exception ex)
            {
                MessageBox.Show(ex.Message, "invalid port!", MessageBoxButton.OK, MessageBoxImage.Exclamation);
            }

        }

        private void btnData_Click_1(object sender, RoutedEventArgs e)
        {


             Update();


        }
        private void Update()
        {
            
          
          
  this.Dispatcher.BeginInvoke(System.Windows.Threading.DispatcherPriority.Normal,
                (ThreadStart)delegate ()
                {

                    try
                    {
                        if (sp1.IsOpen)
                        {
                            txtReceive.Text += sp1.ReadExisting();

                        }
                    }
                    catch (Exception ex)
                    {
                        MessageBox.Show(ex.Message, "Message", MessageBoxButton.OK, MessageBoxImage.Error);

                    }
                }
                       );


        }
    }
}

#xaml file

<Window x:Class="WpfApp3.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:ports="clr-namespace:System.IO.Ports;assembly=System"
        xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
        xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
        xmlns:local="clr-namespace:WpfApp3"
        mc:Ignorable="d"
        Title="MainWindow" Height="450" Width="800">
    <Window.Resources>
        <ObjectDataProvider ObjectType="{x:Type ports:SerialPort}" MethodName="GetPortNames" x:Key="portNames"/>
    </Window.Resources>
    <Grid>
        <ComboBox x:Name="cboPort1" ItemsSource="{Binding Source={StaticResource portNames}}" SelectionChanged="ComboBox_SelectChanged"  HorizontalAlignment="Left" Margin="94,165,0,0" VerticalAlignment="Top" Width="120" RenderTransformOrigin="0.394,1.71"/>
        <TextBlock x:Name ="statussq" HorizontalAlignment="Left" Margin="94,0,0,0" TextWrapping="Wrap" VerticalAlignment="Center" Height="25" Width="120"><Run Language="de-de" Text="Status:"/></TextBlock>
        <TextBox x:Name="txtReceive" HorizontalAlignment="Left" Margin="343,217,0,0" TextWrapping="Wrap" Text="TextBox" VerticalAlignment="Top" Width="198" Height="154"/>
        <Button x:Name ="btnScan" Content="Scan" HorizontalAlignment="Left" Margin="343,167,0,0" VerticalAlignment="Top" Width="75" Click="Button_Click"/>
        <Button x:Name="btnData" Content="Serial Code" HorizontalAlignment="Left" Margin="446,170,0,0" VerticalAlignment="Top" Click="btnData_Click_1"/>
    </Grid>
</Window>