How to use barcode scanner in C# Windows Forms Application?

using System;
using System.Text;
using System.Drawing;
using OnBarcode.Barcode.BarcodeScanner;

namespace OnBarcodeReaderWinFormsDotNetCoreDemo
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
            //  Initial Controls
            this.tbFilePath.ReadOnly = true;
            this.cbBarcodeType.Items.AddRange(new String[] {
                "AustraliaPost", "Codabar", "Code39", "Code39Extension", "Code93",
                "Code128", "DataMatrix", "EAN8", "EAN13", "Identcode",
                "IntelligentMail", "Interleaved2of5", "ISBN", "ISSN", "ITF14",
                "Leitcode", "PatchCode", "PDF417", "Planet", "Postnet",
                "QRCode", "RM4SCC", "UPCA", "UPCE"
            });
            //  Default Barcode Type: Code 128
            this.cbBarcodeType.SelectedIndex = 5;
            this.btScanImage.Enabled = false;
            this.tbScanResult.ReadOnly = true;
            this.tbScanResult.Multiline = true;
        }

        private void btChooseFile_Click(object sender, EventArgs e)
        {
            OpenFileDialog openFileDialog = new OpenFileDialog();
            if (openFileDialog.ShowDialog() == DialogResult.OK)
            {
                try
                {
                    this.tbFilePath.Text = openFileDialog.FileName;
                    this.btScanImage.Enabled = true;
                }
                catch (Exception) { }
            }
        }

        private void btScanImage_Click(object sender, EventArgs e)
        {
            try
            {
                String filePath = this.tbFilePath.Text;
                if (String.IsNullOrEmpty(filePath))
                    throw new Exception("File path is null or empty.");
                if (!File.Exists(filePath))
                    throw new Exception("File does not exist.");

                //  Get enum BarcodeType from ComboBox selected index.
                BarcodeType barcodeType = (BarcodeType)this.cbBarcodeType.SelectedIndex;

                String[] result = BarcodeScanner.Scan(filePath, barcodeType);

                //  Show scan result in the scan result TextBox.
                StringBuilder sb = new StringBuilder();
                if (result.Length > 0)
                {
                    sb.Append("Number of Barcode: " + result.Length + "\r\n");
                    foreach (String s in result)
                        sb.Append("Message: '" + s + "'\r\n");
                }
                else
                {
                    sb.Append("No Barcode Found.");
                }

                this.tbScanResult.Text = sb.ToString();
            }
            catch (Exception ex)
            {
                MessageBox.Show(ex.Message, "Error", MessageBoxButtons.OK, MessageBoxIcon.Error);
            }
        }
    }
}

            ScanOptions opts = new ScanOptions(BarcodeType.Code128);
            opts.EnableGS1 = true;

            BarcodeDetail[] result = BarcodeScanner.Scan("C://Input//gs1-sample.png", opts);
            foreach (BarcodeDetail b in result)
            {
                //  Indicate if the barcode is conform to GS1 specification.
                if (b.IsGS1Compitable)
                {
                    //  Get message in string format.
                    //  Eg. "(415)5412345678908(3911)710125"
                    String msg = b.GetMessage();
                    Console.WriteLine("Data: '{0}'", b.Data);
                    Console.WriteLine("Message: {0}", msg);
                }
            }

            ScanOptions opts = new ScanOptions(new List<BarcodeType> { 
                BarcodeType.QRCode, BarcodeType.Code128 });

            String[] sourceImageFiles = new String[] {
                        "SourceImage01.png",
                        "SourceImage02.png"
            };

            BarcodeDetail[] datas = BarcodeScanner.Scan(sourceImageFiles, opts);

            foreach (BarcodeDetail obj in datas)
            {
                Console.WriteLine("Message: '" + obj.GetMessage() + "'");
                //  Show index and file path of the source image in the input array.
                //  SourceFilePath is empty if the input is file streams or Bitmap objects.
                Console.WriteLine(" Source: Index=" + obj.SourceIndex + "; Source Path: " + obj.SourceFilePath);
                Console.WriteLine(" Barcode Text: " + obj.Data + "; Format: " + obj.Type);
            }

            List<SRegion> regions = new List<SRegion>();
            regions.Add(new SRegion(0, 0, 50, 60));
            regions.Add(new SRegion(100, 100, 50, 60));

            string[] barcodes = BarcodeScanner.ScanRegions("qrcode-barcodes.png", BarcodeType.QRCode, regions);

            ScanOptions options = new ScanOptions(BarcodeType.QRCode);
            //  Set maximum number of threads could be used in the scanning.
            //  The valud must be non-negative.
            //  0: disable multi-thread (Default Value)
            //  >0: using multi-thread
            options.SetMaxMultiThreadCount(3);
            BarcodeDetail[] result = BarcodeScanner.Scan(
                new String[] {
                    "SourceImage01.png",
                    "SourceImage02.png",
                    "SourceImage03.png"
                }, options);