Important Update
MainForm.vb
Imports System.ComponentModel
Imports System.Drawing
Imports System.Media
Imports System.Reflection
Imports System.Text
Imports System.Threading
Imports System.Windows.Forms
Imports Bytescout.BarCodeReader
Imports TouchlessLib
Public Class MainForm
' Scan delay, ms.
Const SCAN_DELAY As Integer = 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)
Dim ReadOnly _touchlessLibManager As TouchlessMgr
' Background thread for barcode scanning
Dim ReadOnly _backgroundWorker As New BackgroundWorker
' Synchronization event
Dim ReadOnly _synchronizationEvent As New AutoResetEvent(False)
' Form constructor
Public Sub New()
InitializeComponent()
' Create Touchless library manager
_touchlessLibManager = New TouchlessMgr()
' Setup background worker
_backgroundWorker.WorkerSupportsCancellation = True
AddHandler _backgroundWorker.DoWork, AddressOf BackgroundWorker_DoWork
AddHandler _backgroundWorker.RunWorkerCompleted, AddressOf BackgroundWorker_RunWorkerCompleted
End Sub
' On form loading
Private Sub MainForm_Load(sender As Object, e As EventArgs) Handles MyBase.Load
' Fill devices combobox with available video cameras
For Each camera As Camera In _touchlessLibManager.Cameras
cmbCamera.Items.Add(camera)
Next
' Select the first available camera. See also cmbCamera_SelectedIndexChanged event handler.
If _touchlessLibManager.Cameras.Count > 0 Then
cmbCamera.SelectedItem = _touchlessLibManager.Cameras(0)
Else
MessageBox.Show("No video camera available. Please connect the camera.")
End If
' Populate barcode types combobox
PopulateBarcodeTypesCombobox()
' Select some default barcode type
cmbBarcodeType.SelectedItem = "QRCode"
End Sub
Private Sub PopulateBarcodeTypesCombobox()
cmbBarcodeType.Items.Clear()
For Each propertyInfo As PropertyInfo In GetType(BarcodeTypeSelector).GetProperties()
cmbBarcodeType.Items.Add(propertyInfo.Name)
Next
End Sub
' On camera selected
Private Sub cmbCamera_SelectedIndexChanged(sender As Object, e As EventArgs) Handles cmbCamera.SelectedIndexChanged
If _touchlessLibManager.CurrentCamera IsNot Nothing Then
RemoveHandler _touchlessLibManager.CurrentCamera.OnImageCaptured, AddressOf CurrentCamera_OnImageCaptured
End If
If cmbCamera.SelectedIndex <> -1 Then
Dim camera As Camera = _touchlessLibManager.Cameras(cmbCamera.SelectedIndex)
If camera IsNot Nothing Then
' Set camera output image dimensions
camera.CaptureWidth = Integer.Parse(tbCameraWidth.Text)
camera.CaptureHeight = Integer.Parse(tbCameraHeight.Text)
AddHandler camera.OnImageCaptured, AddressOf CurrentCamera_OnImageCaptured
' Select the camera
_touchlessLibManager.CurrentCamera = camera
End If
End If
End Sub
Private Sub btnUpdateCameraImageDimensions_Click(sender As Object, e As EventArgs) Handles btnUpdateCameraImageDimensions.Click
If _touchlessLibManager.CurrentCamera IsNot Nothing Then
' Update camera's output image dimensions
_touchlessLibManager.CurrentCamera.CaptureWidth = Integer.Parse(tbCameraWidth.Text)
_touchlessLibManager.CurrentCamera.CaptureHeight = Integer.Parse(tbCameraHeight.Text)
End If
End Sub
Private Sub StartDecoding()
If cmbCamera.SelectedIndex = -1 Then
Return
End If
' Clear the output text box
rtbFoundBarcodes.Clear()
' Check if we have camera selected
If cmbCamera.SelectedIndex <> -1 Then
' Start the decoding in the background thread
Dim barcodeTypesToFind As BarcodeTypeSelector = GetBarcodeTypeFromCombobox()
_backgroundWorker.RunWorkerAsync(barcodeTypesToFind)
UpdateControls(True)
Else
MessageBox.Show("Please select the camera first!")
End If
End Sub
Private Sub StopDecoding()
_backgroundWorker.CancelAsync()
' Wait until BackgroundWorker finished
If _backgroundWorker.IsBusy Then
_synchronizationEvent.WaitOne()
End If
UpdateControls(False)
End Sub
Private Sub UpdateControls(started As Boolean)
If started Then
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
End If
End Sub
Private Sub CurrentCamera_OnImageCaptured(sender As Object, e As CameraEventArgs)
pictureBoxPreview.Image = e.Image
End Sub
Private Sub btnStart_Click(sender As Object, e As EventArgs) Handles btnStart.Click
StartDecoding()
End Sub
Private Sub btnStop_Click(sender As Object, e As EventArgs) Handles btnStop.Click
StopDecoding()
End Sub
' Background thread procedure used by BackgroundWorker
Private Sub BackgroundWorker_DoWork(sender As Object, e As DoWorkEventArgs)
Dim worker As BackgroundWorker = CType(sender, BackgroundWorker)
Dim barcodeTypesToFind As BarcodeTypeSelector = CType(e.Argument, BarcodeTypeSelector)
' Create and setup barcode reader instance
Using reader As New Reader
reader.RegistrationName = "demo"
reader.RegistrationKey = "demo"
reader.BarcodeTypesToFind = barcodeTypesToFind
' Work while not canceled
While True
' Check cancellation
If worker.CancellationPending Then
e.Cancel = True
_synchronizationEvent.Set()
Return
End If
' Get image from camera by invoking method from UI thread
Dim bitmap As Bitmap = CType(Invoke(New GetCameraImageDelegate(AddressOf GetCameraImage)), Bitmap)
If bitmap Is Nothing Then
e.Result = nothing
return
End If
' Search the image for barcodes
Dim result As FoundBarcode() = reader.ReadFrom(bitmap)
' Update UI asynchronously
BeginInvoke(New Action(Of FoundBarcode())(AddressOf UpdateStatus), New Object() { result })
' Pause
Thread.Sleep(SCAN_DELAY)
End While
End Using
End Sub
Delegate Function GetCameraImageDelegate() As Bitmap
Private Function GetCameraImage() As Bitmap
If Not IsDisposed and Not Disposing and _touchlessLibManager.CurrentCamera IsNot Nothing Then
return _touchlessLibManager.CurrentCamera.GetCurrentImage()
End If
Return Nothing
End Function
' Update UI with found barcodes information
Private Sub UpdateStatus(foundBarcodes As FoundBarcode())
If foundBarcodes IsNot Nothing And foundBarcodes.Length > 0 Then
' Play sound if we found any barcode
SystemSounds.Beep.Play()
Dim stringBuilder As StringBuilder = New StringBuilder()
stringBuilder.AppendFormat("Time: {0:HH:mm:ss:tt}", DateTime.Now)
stringBuilder.AppendLine()
' Display found barcodes in the output text box
For Each barcode As FoundBarcode In foundBarcodes
stringBuilder.AppendFormat("Found barcode: {0} {1}", barcode.Type, barcode.Value)
stringBuilder.AppendLine()
Next
rtbFoundBarcodes.Text = stringBuilder.ToString()
' Update status text with number of found barcodes
lblFoundBarcodes.Text = String.Format("Found {0} barcodes:", foundBarcodes.Length)
End If
' Make "Scanning..." label flicker.
lblScanning.Visible = Not lblScanning.Visible
lblScanning.Refresh()
' Check if we need to stop on first barcode found
If cbStopOnFirstBarcode.Checked And foundBarcodes IsNot Nothing And foundBarcodes.Length > 0 Then
StopDecoding()
End If
End Sub
' Background thread is finished
Private Sub BackgroundWorker_RunWorkerCompleted(sender As Object, e As RunWorkerCompletedEventArgs)
' Update UI asynchronously
BeginInvoke(New Action(Of RunWorkerCompletedEventArgs)(AddressOf OnBackgroundWorkerFinished), New Object() {e})
End Sub
Private Sub OnBackgroundWorkerFinished(completedEventArgs As RunWorkerCompletedEventArgs)
If completedEventArgs.Cancelled Then
lblScanning.Text = "Stopped"
ElseIf completedEventArgs.Error IsNot Nothing Then
lblScanning.Text = "Error: " + completedEventArgs.Error.Message
Else
lblScanning.Text = "Done!"
End If
UpdateControls(False)
End Sub
Private Function GetBarcodeTypeFromCombobox() As BarcodeTypeSelector
Dim result As BarcodeTypeSelector = New BarcodeTypeSelector()
Dim selectedBarcodeTypeName As String = CType(cmbBarcodeType.SelectedItem, String)
Dim propertyInfo As PropertyInfo = GetType(BarcodeTypeSelector).GetProperty(selectedBarcodeTypeName)
propertyInfo.SetValue(result, True, Nothing)
Return result
End Function
Protected Overrides Sub OnClosing(e As CancelEventArgs)
StopDecoding()
_touchlessLibManager.Dispose()
MyBase.OnClosing(e)
End Sub
Private Sub btnExit_Click(sender As Object, e As EventArgs) Handles btnExit.Click
DialogResult = DialogResult.OK
Close()
End Sub
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Try
if _touchlessLibManager.CurrentCamera IsNot Nothing
_touchlessLibManager.CurrentCamera.ShowPropertiesDialog(Handle)
End If
Catch ex As Exception
MessageBox.Show(ex.Message)
End Try
End Sub
End Class
Program.vb
Imports System.Collections.Generic Imports System.Windows.Forms NotInheritable Class Program Private Sub New() End Sub ''' <summary> ''' The main entry point for the application. ''' </summary> <MTAThread> _ Friend Shared Sub Main() Application.EnableVisualStyles() Application.SetCompatibleTextRenderingDefault(False) Dim dlg As New MainForm() dlg.ShowDialog() End Sub End Class