How to Read Barcode in WPF with VB.NET
We’re proud to reveal that Dynamsoft’s Dynamic .NET TWAIN 5.0 is on its way to release soon. In addition to WinForms support, the new version will include a WPF control. You can use it in your WPF app to capture images from TWAIN scanners and UVC/WIA webcams, to edit and save images to local disks, to a server or a database. Today, I’d like to cover how, using VB.NET, you can use the Dynamic .NET TWAIN 5.0 SDK to implement barcode reading in a WPF application.
The relevant source code can be downloaded here.
1. Create a New WPF Project
First, start Visual Studio .NET, and create a new WPF project. Select Visual Basic as the type and choose WPF Application as the template.
2. Add a Reference
Right-click on the project root, and select Add Reference… from the menu. Click Browse to locate DynamicDotNetTWAIN.dll and add it.
3. Add Dynamic .NET TWAIN Component
If there is no Dynamic .NET TWAIN component available, you might need to open the toolbox. To do so, right-click on the panel and select Choose Items… Switch to the tab WPF Components and click Browse… to load DynamicDotNetTWAIN.Wpf.dll
4. Add Buttons and Textbox
Next, you’ll want to drag two buttons and one textbox from the toolbox to design a form. The buttons are used to load an image and make the detection of a barcode. And, the textbox is used to display the information decoded from barcode.
5. Code for Loading Image
Now, what you need to do is to acquire an image using the Windows standard API. Then you’ll need to load it using the Dynamic .NET TWAIN component method. Just a couple of lines of code are needed for loading an image. It’s pretty simple.
Dim filedlg As OpenFileDialog filedlg = New OpenFileDialog() filedlg.Multiselect = True Dim strFilename As String If (filedlg.ShowDialog() = DialogResult.OK) Then For Each strFilename In filedlg.FileNames DynamicDotNetTwain1.LoadImage(strFilename) Next End If
6. Code for Barcode Recognition
To decode a barcode, the path for the barcode library needs to be first be specified. Then, with one additional line of code, you’ll get results.
Set the path of barcode library
Dim strDllFolder As String strDllFolder = Application.ExecutablePath Dim pos As Integer pos = strDllFolder.LastIndexOf("\Samples\") If (pos <> -1) Then strDllFolder = strDllFolder.Substring(0, strDllFolder.IndexOf("\", pos)) + "\Bin\BarcodeResources\" End If Me.DynamicDotNetTwain1.BarcodeDllPath = strDllFolder
Get the results and display them on screen
Me.TextBox1.Text = "" Dim aryResult() As Result aryResult = Me.DynamicDotNetTwain1.ReadBarcode(Me.DynamicDotNetTwain1.CurrentImageIndexInBuffer, BarcodeFormat.All) Dim strText As StringBuilder strText = New StringBuilder() If aryResult.Length = 1 Then strText.AppendFormat(aryResult.Length & " total barcode" & ("") & " found." & Constants.vbCrLf) Else strText.AppendFormat(aryResult.Length & " total barcode" & ("s") & " found." & Constants.vbCrLf) End If For i As Integer = 0 To aryResult.Length - 1 Dim objResult As Result objResult = aryResult(i) strText.AppendFormat(" Result " & (i + 1) & Constants.vbCrLf) strText.AppendFormat(" BarcodeFormat: " & objResult.BarcodeFormat.ToString() & Constants.vbCrLf) strText.AppendFormat(" Text read: " & objResult.Text & Constants.vbCrLf) Next i Me.TextBox1.Text = strText.ToString()
I hope this brief tutorial is helpful to anyone who is looking for a .NET barcode reader SDK in VB.NET.
For further inquiries, please feel free to send me an email at kgao[at]dynamsoft.com.
Dynamic .NET TWAIN 5.0 is scheduled to be released late next month. To stay informed about all our product announcements, blog posts and more, be sure to follow us on Twitter, like us on Facebook or add us on Google+. Also, if you’d like to be amongst the first to try out the new version first, please contact support[at]dynamsoft.com.