Reading Barcodes

Take the following steps to start a project:

  1. Start Visual Studio .NET.

  2. Choose File->New->Project... from the menu.

  3. In the New Project dialog box, Choose either "Visual C# Projects" or "VB Projects" in the Projects Type List, and choose "Windows Application" (or "Windows Forms Application" in Visual Studio 2010) in the Templates List.

  4. Type the project name as "ReadingBarcodes" in the Project Name field, and then choose OK. If desired, type a new location for your project or select a directory using the Browse button, and then choose OK.

  5. In the "Solution Explorer" window, right-click on the "References" folder, and select "Add Reference..." from the context menu. In the Add Reference dialog box, select the ".NET" tab and browse to the "C:\LEADTOOLS 19\Bin\DotNet\Win32" folder (or "C:\LEADTOOLS 19\Bin\DotNet4\Win32" if you are going to use .NET 4) and select the following DLLs:

    • Leadtools.dll
    • Leadtools.Forms.dll
    • Leadtools.Barcode.dll
    • Leadtools.Barcode.OneD.dll
    • Leadtools.Codecs.dll
    • Leadtools.Codecs.Tif.dll
    • Leadtools.Codecs.Fax.dll

    Click the Select button and then press the OK button to add the above DLLs to the application.

  6. Switch to Form1 code view (right-click Form1 in the solution explorer then select View Code ) and add the following lines at the beginning of the file:

    C#
    VB
    Imports Leadtools 
          Imports Leadtools.Codecs 
          Imports Leadtools.Forms 
          Imports Leadtools.Barcode 
    using Leadtools; 
          using Leadtools.Codecs; 
          using Leadtools.Forms; 
          using Leadtools.Barcode; 

  7. Drag and drop two buttons in Form1. Change the following properties:

    Property Value
    Name loadImageButton
    Text Load image
    Name readBarcodesButton
    Text Read barcodes
  8. Add the following private variables to Form1

    C#
    VB
    Private barcodeEngineInstance As BarcodeEngine ' The barcode engine 
    Private theImage As RasterImage ' The current loaded image 
    Private imageFileName As String ' Last file name we loaded, this is used in the "Writing Barcodes" tutorial 
    private BarcodeEngine barcodeEngineInstance; // The barcode engine 
    private RasterImage theImage; // The current loaded image 
    private string imageFileName; // Last file name we loaded, this is used in the "Writing Barcodes" tutorial 

  9. Add the following initialization code to Form1

    C#
    VB
    Protected Overrides Sub OnLoad(ByVal e As EventArgs) 
       ' Use the developer and license file by LEADTOOLS 
       Dim MY_LICENSE_FILE As String = "d:\temp\TestLic.lic" 
       Dim MY_DEVELOPER_KEY As String = "xyz123abc" 
       RasterSupport.SetLicense(MY_LICENSE_FILE, MY_DEVELOPER_KEY) 
                     
       ' Create the BarcodeEngine instance 
       barcodeEngineInstance = New BarcodeEngine() 
                     
       MyBase.OnLoad(e) 
    End Sub 
    protected override void OnLoad(EventArgs e) 
    { 
       // Replace the keys with unlock support string provided by LEADTOOLS, or use the evaluation kernel 
                     
       // Unlock reading 1D barcodes 
       string MY_LICENSE_FILE = "d:\\temp\\TestLic.lic"; 
       string MY_DEVELOPER_KEY = "xyz123abc"; 
       RasterSupport.SetLicense(MY_LICENSE_FILE, MY_DEVELOPER_KEY); 
                     
       // Create the BarcodeEngine instance 
       barcodeEngineInstance = new BarcodeEngine(); 
                     
       base.OnLoad(e); 
    } 

  10. Add the following clean up code to Form1

    C#
    VB
    Protected Overrides Sub OnFormClosed(ByVal e As FormClosedEventArgs) 
       ' Delete our resources 
                     
       If Not theImage Is Nothing Then 
          theImage.Dispose() 
       End If 
                     
       MyBase.OnFormClosed(e) 
    End Sub 
    protected override void OnFormClosed(FormClosedEventArgs e) 
    { 
       // Delete our resources 
                     
       if(theImage != null) 
       { 
          theImage.Dispose(); 
       } 
                     
       base.OnFormClosed(e); 
    } 

  11. Add the following code to loadImageButton click procedure:

    C#
    VB
    Private Sub loadImageButton_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles loadImageButton.Click 
       Dim fileName As String = "C:\Users\Public\Documents\LEADTOOLS Images\Barcode1.tif" 
       ' Or comment out the following to load your own file 
       ' Using dlg As New OpenFileDialog 
       '    If dlg.ShowDialog(Me) = System.Windows.Forms.DialogResult.OK Then 
       '       fileName = dlg.FileName 
       '    Else 
       '       Return 
       '    End If 
       ' End Using 
                     
       ' Load the image 
       Using codecs As New RasterCodecs 
          Dim newImage As RasterImage = codecs.Load(fileName, 0, CodecsLoadByteOrder.BgrOrGray, 1, 1) 
                     
          ' Delete old image if any 
          If Not theImage Is Nothing Then 
             theImage.Dispose() 
          End If 
                     
          theImage = newImage 
          imageFileName = fileName 
       End Using 
    End Sub 
    private void loadImageButton_Click(object sender, EventArgs e) 
    { 
       string fileName = @"C:\Users\Public\Documents\LEADTOOLS Images\Barcode1.tif"; 
       // Or comment out the following to load your own file 
       //using(OpenFileDialog dlg = new OpenFileDialog()) 
       //{ 
       //   if(dlg.ShowDialog(this) == System.Windows.Forms.DialogResult.OK) 
       //   { 
       //      fileName = dlg.FileName; 
       //   } 
       //   else 
       //   { 
       //      return; 
       //   } 
       //} 
                     
       // Load the image 
       using(RasterCodecs codecs = new RasterCodecs()) 
       { 
          string fileName = @"C:\Users\Public\Documents\LEADTOOLS Images\Barcode1.tif"; 
          RasterImage newImage = codecs.Load(fileName, 0, CodecsLoadByteOrder.BgrOrGray, 1, 1); 
                     
          // Delete old image if any 
          if(theImage != null) 
          { 
             theImage.Dispose(); 
          } 
                     
          theImage = newImage; 
          imageFileName = fileName; 
       } 
    } 

  12. Add the following code to readBarcodesButton click procedure:

    C#
    VB
    Private Sub readBarcodesButton_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles readBarcodesButton.Click 
       If theImage Is Nothing 
          MessageBox.Show("Load an image first") 
          Return 
       End If 
                     
       Try 
          ' Read all the barcodes 
          ' The first parameter is the image from which to read the barcodes. 
          ' The second parameter is the search rectangle. Pass an empty rectangle to indicate the entire image. 
          ' The third parameter is the maximum number of barcodes to read. Pass 0 for all found in the image. 
          ' The last parameter is an array of the BarcodeSymbology we are interested in. Pass null (or Nothing) 
          ' to indicate that we do not care, and want all available barcodes to be read (found in the image and supported by 
          ' the current unlock support mechanism) 
          Dim dataArray() As BarcodeData = barcodeEngineInstance.Reader.ReadBarcodes(theImage, LogicalRectangle.Empty, 0, Nothing) 
                     
          Dim sb As New StringBuilder() 
          sb.AppendFormat("{0} barcode(s) found", dataArray.Length) 
          sb.AppendLine() 
                     
          For i As Integer = 0 To dataArray.Length - 1 
             Dim data As BarcodeData = dataArray(i) 
                     
             sb.AppendFormat("Symbology: {0}, Location: {1}, Data: {2}", data.Symbology.ToString(), data.Bounds.ToString(), data.Value) 
             sb.AppendLine() 
          Next 
                     
          MessageBox.Show(sb.ToString()) 
       Catch ex As Exception 
          MessageBox.Show(ex.Message) 
       End Try 
    End Sub 
    private void readBarcodesButton_Click(object sender, EventArgs e) 
    { 
       if(theImage == null) 
       { 
          MessageBox.Show("Load an image first"); 
          return; 
       } 
                     
       try 
       { 
          // Read all the barcodes 
          // The first parameter is the image we want to read the barcodes from 
          // The second parameter is the search rectangle. Pass an empty rectangle to indicate the entire image. 
          // The third parameter is the maximum number of barcodes to read. Pass 0 for all barcodes found in the image. 
          // Last parameter is an array of the BarcodeSymbology we are interested in. Pass null (or Nothing) 
          // to indicate that we do not care, and want all barcodes available to be read(that have been found in the image and are supported by 
          // the current unlock support mechanism) 
          BarcodeData[] dataArray = barcodeEngineInstance.Reader.ReadBarcodes(theImage, LogicalRectangle.Empty, 0, null); 
                     
          StringBuilder sb = new StringBuilder(); 
          sb.AppendFormat("{0} barcode(s) found", dataArray.Length); 
          sb.AppendLine(); 
                     
          for(int i = 0; i < dataArray.Length; i++) 
          { 
             BarcodeData data = dataArray[i]; 
                     
             sb.AppendFormat("Symbology: {0}, Location: {1}, Data: {2}", data.Symbology.ToString(), data.Bounds.ToString(), data.Value); 
             sb.AppendLine(); 
          } 
                     
          MessageBox.Show(sb.ToString()); 
       } 
       catch(Exception ex) 
       { 
          MessageBox.Show(ex.Message); 
       } 
    } 

  13. Build, and Run the program to test it. Click "Load Image" to load the image and "Read Barcodes" to search for and show the 1D barcodes that have been read.
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