using System;
using System.Windows.Forms;

namespace ReadFromVideoCamera
{
    static class Program
    {
        /// <summary>
        /// The main entry point for the application.
        /// </summary>
        [MTAThread]
        static void Main()
        {
            Application.EnableVisualStyles();
            Application.SetCompatibleTextRenderingDefault(false);

            MainForm dlg = new MainForm();
            dlg.ShowDialog();
        }
    }
}

using System;
using System.ComponentModel;
using System.Drawing;
using System.Media;
using System.Reflection;
using System.Text;
using System.Windows.Forms;
using System.Threading;
using Bytescout.BarCodeReader;
using TouchlessLib;


namespace ReadFromVideoCamera
{
    public partial class MainForm: Form
    {
        // Scan delay, ms.
        const int SCAN_DELAY = 1500; // scan barcodes every 1.5 sec

        // Touchless SDK library manager (to use it you should have TouchlessLib.dll referenced and WebCamLib.dll in the build output directory)
        readonly TouchlessMgr _touchlessLibManager;

        // Background thread for barcode scanning
        readonly BackgroundWorker _backgroundWorker = new BackgroundWorker();
        // Synchronization event
        readonly AutoResetEvent _synchronizationEvent = new AutoResetEvent(false);

        // Form constructor
        public MainForm()
        {
            InitializeComponent();

            // Create Touchless library manager
            _touchlessLibManager = new TouchlessMgr();

            // Setup background worker
            _backgroundWorker.WorkerSupportsCancellation = true;
            _backgroundWorker.DoWork += BackgroundWorker_DoWork;
            _backgroundWorker.RunWorkerCompleted += BackgroundWorker_RunWorkerCompleted;
        }

        // On form loading 
        private void Form_Load(object sender, EventArgs e)
        {
            // Fill devices combobox with available video cameras
            foreach (Camera camera in _touchlessLibManager.Cameras)
                cmbCamera.Items.Add(camera);

            // Select the first available camera. See also cmbCamera_SelectedIndexChanged event handler.
            if (_touchlessLibManager.Cameras.Count > 0)
                cmbCamera.SelectedItem = _touchlessLibManager.Cameras[0];
            else
                MessageBox.Show("No video camera available. Please connect the camera.");

            // Populate barcode types combobox
            PopulateBarcodeTypesCombobox();
            // Select some default barcode type
            cmbBarcodeType.SelectedItem = "QRCode";
        }

        protected void PopulateBarcodeTypesCombobox()
        {
            cmbBarcodeType.Items.Clear();

            foreach (PropertyInfo propertyInfo in typeof(BarcodeTypeSelector).GetProperties())
                cmbBarcodeType.Items.Add(propertyInfo.Name);
        }

        // On camera selected
        private void cmbCamera_SelectedIndexChanged(object sender, EventArgs e)
        {
            if (_touchlessLibManager.CurrentCamera != null)
                _touchlessLibManager.CurrentCamera.OnImageCaptured -= CurrentCamera_OnImageCaptured;

            if (cmbCamera.SelectedIndex != -1)
            {
                Camera camera = _touchlessLibManager.Cameras[cmbCamera.SelectedIndex];

                if (camera != null)
                {
                    // Set camera output image dimensions
                    camera.CaptureWidth = int.Parse(tbCameraWidth.Text);
                    camera.CaptureHeight = int.Parse(tbCameraHeight.Text);

                    camera.OnImageCaptured += CurrentCamera_OnImageCaptured;

                    // Select the camera
                    _touchlessLibManager.CurrentCamera = camera;
                }
            }
        }

        private void btnUpdateCameraImageDimensions_Click(object sender, EventArgs e)
        {
            if (_touchlessLibManager.CurrentCamera != null)
            {
                // Update camera's output image dimensions
                _touchlessLibManager.CurrentCamera.CaptureWidth = int.Parse(tbCameraWidth.Text);
                _touchlessLibManager.CurrentCamera.CaptureHeight = int.Parse(tbCameraHeight.Text);
            }
        }

        public void StartDecoding()
        {
            if (cmbCamera.SelectedIndex == -1)
                return;

            // Clear the output text box
            rtbFoundBarcodes.Clear();

            // Check if we have camera selected
            if (cmbCamera.SelectedIndex != -1)
            {
                // Start the decoding in the background thread
                BarcodeTypeSelector barcodeTypesToFind = GetBarcodeTypeFromCombobox();
                _backgroundWorker.RunWorkerAsync(barcodeTypesToFind);

                UpdateControls(true);
            }
            else
            {
                MessageBox.Show("Please select the camera first!");
            }
        }

        private void StopDecoding()
        {
            _backgroundWorker.CancelAsync();

            // Wait until BackgroundWorker finished
            if (_backgroundWorker.IsBusy)
                _synchronizationEvent.WaitOne();

            UpdateControls(false);
        }

        void UpdateControls(bool started)
        {
            if (started)
            {
                btnStart.Enabled = false;
                btnStop.Enabled = true;
                cmbBarcodeType.Enabled = false;
                cmbCamera.Enabled = false;
                tbCameraHeight.Enabled = false;
                tbCameraWidth.Enabled = false;
                btnUpdateCameraImageDimensions.Enabled = false;
                cbStopOnFirstBarcode.Enabled = false;
                lblScanning.Visible = true;
                lblScanning.Text = "Scanning...";
            }
            else
            {
                btnStart.Enabled = true;
                btnStop.Enabled = false;
                cmbBarcodeType.Enabled = true;
                cmbCamera.Enabled = true;
                cbStopOnFirstBarcode.Enabled = true;
                tbCameraHeight.Enabled = true;
                tbCameraWidth.Enabled = true;
                btnUpdateCameraImageDimensions.Enabled = true;
                lblScanning.Visible = true;
            }
        }

        void CurrentCamera_OnImageCaptured(object sender, CameraEventArgs e)
        {
            pictureBoxPreview.Image = e.Image;
        }

        private void btnStart_Click(object sender, EventArgs e)
        {
            StartDecoding();
        }

        private void btnStop_Click(object sender, EventArgs e)
        {
            StopDecoding();
        }

        // Background thread procedure used by BackgroundWorker
        public void BackgroundWorker_DoWork(object sender, DoWorkEventArgs e)
        {
            BackgroundWorker worker = (BackgroundWorker) sender;
            BarcodeTypeSelector barcodeTypesToFind = (BarcodeTypeSelector) e.Argument;

            // Create and setup barcode reader instance
            using (Reader reader = new Reader())
            {
                reader.RegistrationName = "demo";
                reader.RegistrationKey = "demo";

                reader.BarcodeTypesToFind = barcodeTypesToFind;

                // Work while not canceled
                while (true)
                {
                    // Check cancellation
                    if (worker.CancellationPending)
                    {
                        e.Cancel = true;
                        _synchronizationEvent.Set();
                        return;
                    }

                    // Get image from camera by invoking method from UI thread
                    Bitmap bitmap = (Bitmap) Invoke(new GetCameraImageDelegate(GetCameraImage));
                    if (bitmap == null)
                    {
                        e.Result = null;
                        return;
                    }

                    /* -----------------------------------------------------------------------
                    NOTE: We can read barcodes from specific page to increase performance.
                    For sample please refer to "Decoding barcodes from PDF by pages" program.
                    ----------------------------------------------------------------------- */

                    // Search the image for barcodes
                    FoundBarcode[] result = reader.ReadFrom(bitmap);

                    // Update UI asynchronously
                    BeginInvoke(new Action<FoundBarcode[]>(UpdateStatus), new object[] { result });

                    // Pause
                    Thread.Sleep(SCAN_DELAY);
                }
            }
        }

        delegate Bitmap GetCameraImageDelegate();

        Bitmap GetCameraImage()
        {
            if (!IsDisposed && !Disposing && _touchlessLibManager.CurrentCamera != null)
                return _touchlessLibManager.CurrentCamera.GetCurrentImage();

            return null;
        }

        // Update UI with found barcodes information
        void UpdateStatus(FoundBarcode[] foundBarcodes)
        {
            if (foundBarcodes != null && foundBarcodes.Length > 0)
            {
                // Play sound if we found any barcode
                SystemSounds.Beep.Play();

                StringBuilder stringBuilder = new StringBuilder();

                stringBuilder.AppendFormat("Time: {0:HH:mm:ss:tt}", DateTime.Now);
                stringBuilder.AppendLine();

                // Display found barcodes in the output text box
                foreach (FoundBarcode barcode in foundBarcodes)
                {
                    stringBuilder.AppendFormat("Found barcode: {0} {1}", barcode.Type, barcode.Value);
                    stringBuilder.AppendLine();
                }

                rtbFoundBarcodes.Text = stringBuilder.ToString();

                // Update status text with number of found barcodes
                lblFoundBarcodes.Text = string.Format("Found {0} barcodes:", foundBarcodes.Length);
            }

            // Make "Scanning..." label flicker.
            lblScanning.Visible = !lblScanning.Visible;
            lblScanning.Refresh();

            // Check if we need to stop on first barcode found
            if (cbStopOnFirstBarcode.Checked && foundBarcodes != null && foundBarcodes.Length > 0)
            {
                StopDecoding();
            }
        }

        // Background thread is finished
        private void BackgroundWorker_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e)
        {
            // Update UI asynchronously
            BeginInvoke(new Action<RunWorkerCompletedEventArgs>(OnBackgroundWorkerFinished), new object[] { e });
        }

        void OnBackgroundWorkerFinished(RunWorkerCompletedEventArgs completedEventArgs)
        {
            if (completedEventArgs.Cancelled)
            {
                lblScanning.Text = "Stopped";
            }
            else if (completedEventArgs.Error != null)
            {
                lblScanning.Text = "Error: " + completedEventArgs.Error.Message;
            }
            else
            {
                lblScanning.Text = "Done!";
            }

            UpdateControls(false);
        }

        // Gets selected barcode type
        private BarcodeTypeSelector GetBarcodeTypeFromCombobox()
        {
            BarcodeTypeSelector result = new BarcodeTypeSelector();

            string selectedBarcodeTypeName = (string) cmbBarcodeType.SelectedItem;

            PropertyInfo propertyInfo = typeof(BarcodeTypeSelector).GetProperty(selectedBarcodeTypeName);
            propertyInfo.SetValue(result, true, null);

            return result;
        }

        protected override void OnClosing(CancelEventArgs e)
        {
            StopDecoding();

            _touchlessLibManager.Dispose();

            base.OnClosing(e);
        }

        private void btnExit_Click(object sender, EventArgs e)
        {
            DialogResult = DialogResult.OK;
            Close();
        }

        private void btnCameraProperties_Click(object sender, EventArgs e)
        {
            try
            {
                if (_touchlessLibManager.CurrentCamera != null)
                    _touchlessLibManager.CurrentCamera.ShowPropertiesDialog(Handle);
            }
            catch (Exception exception)
            {
                MessageBox.Show(exception.Message);
            }
        }
    }
}