Important Update
ByteScout tutorials are designed to explain the code for both VB.NET beginners and advanced programmers. ByteScout BarCode Reader SDK: the SDK for barcode decoding. Can read all popular types from Code 128, GS1, UPC and Code 39 to QR Code, Datamatrix, PDF417. Images, pdf, TIF images and live web camera are supported as input. Designed to handle documents with noise and defects. Includes optional splitter and merger for pdf and tiff based on barcodes. Batch mode is optimized for high performance with multiple threads. Decoded values can be exported to XML, JSON, CSV or into custom data format. It can read barcode from live video cam (simplified) in VB.NET.
VB.NET code samples for VB.NET developers help to speed up coding of your application when using ByteScout BarCode Reader SDK. Just copy and paste the code into your VB.NET application’s code and follow the instruction. Code testing will allow the function to be tested and work properly with your data.
Free trial version of ByteScout BarCode Reader SDK is available on our website. Documentation and source code samples are included.
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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)
' Show barcode decoder dialog and get decoded barcode value
Dim decodedBarcodeValue As String = WebCamBarcodeDecoder.DecodeBarcode()
If decodedBarcodeValue IsNot Nothing Then
MessageBox.Show("Found barcode: " & decodedBarcodeValue)
Else
MessageBox.Show("Decoding cancelled")
End If
End Sub
End Class
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Partial Class WebCamBarcodeDecoder
''' <summary>
''' Required designer variable.
''' </summary>
Private components As System.ComponentModel.IContainer = Nothing
''' <summary>
''' Clean up any resources being used.
''' </summary>
''' <param name="disposing">true if managed resources should be disposed; otherwise, false.</param>
Protected Overrides Sub Dispose(disposing As Boolean)
If disposing AndAlso (components IsNot Nothing) Then
components.Dispose()
End If
MyBase.Dispose(disposing)
End Sub
#Region "Windows Form Designer generated code"
''' <summary>
''' Required method for Designer support - do not modify
''' the contents of this method with the code editor.
''' </summary>
Private Sub InitializeComponent()
Me.pictureVideoPreview = New System.Windows.Forms.PictureBox()
Me.btnCancel = New System.Windows.Forms.Button()
CType(Me.pictureVideoPreview, System.ComponentModel.ISupportInitialize).BeginInit()
Me.SuspendLayout()
'
'pictureVideoPreview
'
Me.pictureVideoPreview.Anchor = CType((((System.Windows.Forms.AnchorStyles.Top Or System.Windows.Forms.AnchorStyles.Bottom) _
Or System.Windows.Forms.AnchorStyles.Left) _
Or System.Windows.Forms.AnchorStyles.Right), System.Windows.Forms.AnchorStyles)
Me.pictureVideoPreview.BackColor = System.Drawing.Color.White
Me.pictureVideoPreview.BorderStyle = System.Windows.Forms.BorderStyle.Fixed3D
Me.pictureVideoPreview.Location = New System.Drawing.Point(12, 12)
Me.pictureVideoPreview.Name = "pictureVideoPreview"
Me.pictureVideoPreview.Size = New System.Drawing.Size(640, 480)
Me.pictureVideoPreview.SizeMode = System.Windows.Forms.PictureBoxSizeMode.CenterImage
Me.pictureVideoPreview.TabIndex = 8
Me.pictureVideoPreview.TabStop = False
'
'btnCancel
'
Me.btnCancel.Anchor = CType((System.Windows.Forms.AnchorStyles.Bottom Or System.Windows.Forms.AnchorStyles.Right), System.Windows.Forms.AnchorStyles)
Me.btnCancel.DialogResult = System.Windows.Forms.DialogResult.Cancel
Me.btnCancel.Font = New System.Drawing.Font("Tahoma", 8.25!, System.Drawing.FontStyle.Bold, System.Drawing.GraphicsUnit.Point, CType(204, Byte))
Me.btnCancel.Location = New System.Drawing.Point(562, 497)
Me.btnCancel.Name = "btnCancel"
Me.btnCancel.Size = New System.Drawing.Size(90, 26)
Me.btnCancel.TabIndex = 4
Me.btnCancel.Text = "Cancel"
Me.btnCancel.UseVisualStyleBackColor = True
'
'WebCamBarcodeDecoder
'
Me.AutoScaleDimensions = New System.Drawing.SizeF(6.0!, 13.0!)
Me.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font
Me.CancelButton = Me.btnCancel
Me.ClientSize = New System.Drawing.Size(664, 536)
Me.Controls.Add(Me.btnCancel)
Me.Controls.Add(Me.pictureVideoPreview)
Me.MaximizeBox = False
Me.Name = "WebCamBarcodeDecoder"
Me.ShowIcon = False
Me.StartPosition = System.Windows.Forms.FormStartPosition.CenterScreen
Me.Text = "QR Code decoder"
CType(Me.pictureVideoPreview, System.ComponentModel.ISupportInitialize).EndInit()
Me.ResumeLayout(False)
End Sub
#End Region
Private pictureVideoPreview As System.Windows.Forms.PictureBox
Private WithEvents btnCancel As System.Windows.Forms.Button
End Class
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Imports System
Imports System.ComponentModel
Imports System.Drawing
Imports System.Windows.Forms
Imports System.Threading
Imports Bytescout.BarCodeReader
Imports TouchlessLib
Partial Public Class WebCamBarcodeDecoder
Inherits Form
' Touchless API library manager (to use it you should have TouchlessLib.dll referenced and WebCamLib.dll copied to the output directory).
Private _touchlessLibManager As TouchlessMgr
' Background barcode decoding thread.
Private ReadOnly _backgroundWorker As New BackgroundWorker()
' Array with all latest barcodes from the last scanning session.
Public FoundBarcode As String = Nothing
' Form initialization.
Public Sub New()
InitializeComponent()
' Setup background working thread
_backgroundWorker.WorkerSupportsCancellation = True
AddHandler _backgroundWorker.DoWork, New DoWorkEventHandler(AddressOf BackgroundWorker_DoWork)
AddHandler _backgroundWorker.RunWorkerCompleted, New RunWorkerCompletedEventHandler(AddressOf BackgroundWorker_RunWorkerCompleted)
End Sub
' On form loading.
Private Sub VideoScanForm_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
' Initialize camera and cancel if no camera avalaible
If InitCamera() = False Then
DialogResult = New DialogResult()
Close()
End If
StartDecoding()
End Sub
' Camera initialization.
Private Function InitCamera() As Boolean
' Create Touchless API library manager to work with web camera
_touchlessLibManager = New TouchlessMgr()
If _touchlessLibManager.Cameras.Count = 0 Then
MessageBox.Show("No camera devices available.")
Return False
End If
' Get first available web camera
Dim camera As Camera = _touchlessLibManager.Cameras(0)
' ... and set it as the current device
_touchlessLibManager.CurrentCamera = camera
' Set camera image dimensions acquired from camera
camera.CaptureWidth = 640
camera.CaptureHeight = 480
' Handle camera's OnImageCaptured event
AddHandler camera.OnImageCaptured, New EventHandler(Of CameraEventArgs)(AddressOf CurrentCamera_OnImageCaptured)
Return True
End Function
Public Sub StartDecoding()
' Start the background decoding thread
_backgroundWorker.RunWorkerAsync()
End Sub
Private Sub StopDecoding()
' Signal the background thread to stop
_backgroundWorker.CancelAsync()
End Sub
Private Sub DeinitCamera()
If _touchlessLibManager IsNot Nothing Then
If _touchlessLibManager.CurrentCamera IsNot Nothing Then
RemoveHandler _touchlessLibManager.CurrentCamera.OnImageCaptured, AddressOf CurrentCamera_OnImageCaptured
_touchlessLibManager.CurrentCamera = Nothing
End If
End If
_touchlessLibManager.Dispose()
_touchlessLibManager = Nothing
End Sub
' Barcode decoding procedure executing in the background thread.
Private Sub BackgroundWorker_DoWork(ByVal sender As Object, ByVal e As DoWorkEventArgs)
Dim worker As BackgroundWorker = TryCast(sender, BackgroundWorker)
' Create barcode reader instance
Dim reader As New Reader()
reader.RegistrationName = "demo"
reader.RegistrationKey = "demo"
' Enable QR Code decoding
reader.BarcodeTypesToFind.QRCode = True
Try
' Get image from camera every 1.5s and try to find a barcode on it
While True
' If the decoding is canceled then exit
If (worker.CancellationPending = True) Then
e.Cancel = True
Return
Else
' get current frame bitmap from camera using Touchless lib
Dim bitmap As Bitmap = _touchlessLibManager.CurrentCamera.GetCurrentImage()
If bitmap IsNot Nothing Then
' -----------------------------------------------------------------------
' NOTE: We can read barcodes from specific page to increase performance .
' For sample please refer to "Decoding barcodes from PDF by pages" program.
' -----------------------------------------------------------------------
' Search barcodes
Dim result As FoundBarcode() = reader.ReadFrom(bitmap)
If result IsNot Nothing And result.Length > 0 Then
' return value of the first found barcode
e.Result = result(0).Value
Return
End If
End If
' Pause the loop for 1.5s
Thread.Sleep(1500)
End If
End While
Finally
reader.Dispose()
End Try
End Sub
' Background thread procedure is finished
Private Sub BackgroundWorker_RunWorkerCompleted(ByVal sender As Object, ByVal e As RunWorkerCompletedEventArgs)
' If decoding is not canceled then get the decoding result from background thread and close the form
If Not e.Cancelled Then
' Get barcode value for background thread result
FoundBarcode = DirectCast(e.Result, String)
' Close form with OK result
DialogResult = DialogResult.OK
Close()
End If
End Sub
' Update picture box with the last captured frame from web camera.
Private Sub CurrentCamera_OnImageCaptured(ByVal sender As Object, ByVal e As CameraEventArgs)
pictureVideoPreview.Image = _touchlessLibManager.CurrentCamera.GetCurrentImage()
End Sub
' Cancel button click.
Private Sub btnCancel_Click(ByVal sender As Object, ByVal e As EventArgs) Handles btnCancel.Click
DialogResult = DialogResult.Cancel
Close()
End Sub
' On form closing.
Private Sub VideoScanForm_FormClosing(ByVal sender As System.Object, ByVal e As System.Windows.Forms.FormClosingEventArgs) Handles MyBase.FormClosing
StopDecoding()
DeinitCamera()
End Sub
' Shared (static) function for convenient use.
' It creates the form and returns the decoded barcode value as string.
' Returns Nothing if the decoding is canceled.
Public Shared Function DecodeBarcode() As String
Dim form As New WebCamBarcodeDecoder()
If form.ShowDialog() = DialogResult.OK Then
Return form.FoundBarcode
End If
Return Nothing
End Function
End Class
60 Day Free Trial or Visit ByteScout BarCode Reader SDK Home Page
Explore ByteScout BarCode Reader SDK Documentation
Explore Samples
Sign Up for ByteScout BarCode Reader SDK Online Training
Get Your API Key
Explore Web API Docs
Explore Web API Samples
60 Day Free Trial or Visit ByteScout BarCode Reader SDK Home Page
Explore ByteScout BarCode Reader SDK Documentation
Explore Samples
Sign Up for ByteScout BarCode Reader SDK Online Training
Get Your API Key
Explore Web API Docs
Explore Web API Samples