VintaSoft Barcode .NET SDK 15.0: Documentation for Web developer
In This Topic
    Recognize barcodes in image in ASP.NET WebForms application
    In This Topic
    This tutorial shows how to create a blank ASP.NET WebForms application in Visual Studio .NET 2019 and recognize barcodes in image in ASP.NET WebForms application.


    Here are steps, which must be done:
    1. Create a blank ASP.NET WebForms application.

      Open Visual Studio .NET 2019 and create a new project, of ASP.NET Web application type, and configure the project to use .NET Framework 4.7.2:

      Select the "Empty" template for ASP.NET Web application and configure the project to use WebForms:

    2. Server side: Add references to the Vintasoft assemblies to ASP.NET WebForms application.

      Add references to the Vintasoft.Barcode.dll, Vintasoft.Shared.dll, Vintasoft.Shared.Web.dll, Vintasoft.Barcode.Web.Services.dll and Vintasoft.Barcode.Web.HttpHandlers.dll assemblies from "<InstallPath>\VintaSoft Barcode .NET v15.0\Bin\DotNet4\AnyCPU\" folder in ASP.NET WebForms application.

    3. Server side: Add generic handler, which allows to recognize barcodes in image, to ASP.NET WebForms application.

      • Add the "Handlers" folder to ASP.NET WebForms application.
      • Press the right mouse button on the "Handlers" folder and select the "Add => New Item..." menu from context menu
      • Select "Generic Handler" template, set the handler name to the "MyVintasoftBarcodeHandler" and press the "Add" button
      • Specify that MyVintasoftBarcodeHandler class is derived from Vintasoft.Barcode.Web.HttpHandlers.VintasoftBarcodeHandler class

        Here are C# source codes of MyVintasoftBarcodeHandler class:
        namespace WebApplication1.Handlers
        {
            /// <summary>
            /// Summary description for MyVintasoftBarcodeHandler
            /// </summary>
            public class MyVintasoftBarcodeHandler : Vintasoft.Barcode.Web.HttpHandlers.VintasoftBarcodeHandler
            {
        
                public bool IsReusable
                {
                    get
                    {
                        return false;
                    }
                }
        
            }
        }
        
    4. Client side: Add Vintasoft JavaScript files to the project.

      • Add the "Scripts" folder to ASP.NET WebForms Web application.

      • Copy Vintasoft.Shared.js and Vintasoft.Barcode.js files from "<InstallPath>\VintaSoft Barcode .NET v15.0\Bin\JavaScript\" folder into "Scripts" folder.
    5. Client side: Add JavaScript code, which recognizes barcodes and displays barcode recognition result, to the Default web form.

      • Create folder "UploadedImageFiles\SessionID" and copy image file with barcodes "<InstallPath>VintaSoft\Barcode .NET v15.0\Images\AllSupportedBarcodes.png" to the folder. We will recognize barcodes in this image.
      • Create the Default web form - file "Default.aspx".
        • Press the right mouse button on the project and select the "Add => WebForm" menu from context menu:
        • Specify "Default" as web form name => created web form will be opened:
      • Add references to Vintasoft JavaScript files:

        Here is HTML code that adds references to Vintasoft JavaScript files:
        <script src="~/Scripts/Vintasoft.Shared.js" type="text/javascript"></script>
        <script src="~/Scripts/Vintasoft.Barcode.js" type="text/javascript"></script>
        
        
      • Add HTML markup (a div element that will display barcode recognition result) to the web view:

        Here is HTML markup code:
        <div id="barcodeInformation"></div>
        
      • Add JavaScript code that recognizes barcodes and displays barcode recognition result:

        Here is JavaScript code that recognizes barcodes and displays barcode recognition result:
        <script type="text/javascript">
        
            /**
             * Barcodes are recognized successfully.
             */
            function __readBarcodes_success(data) {
                if (data.success) {
                    // get the barcode recognition result
                    var barcodeRecognitionResults = data.results;
        
                    var htmlMarkup = '';
                    // if no barcodes found
                    if (barcodeRecognitionResults.length == 0) {
                        htmlMarkup = 'No barcodes found.';
                    }
                    // if barcodes are found
                    else {
                        htmlMarkup = barcodeRecognitionResults.length.toString() + ' barcodes are found.<br />';
                        htmlMarkup += '<br />';
        
                        // for each recognized barcode
                        for (var i = 0; i < barcodeRecognitionResults.length; i++) {
                            // get the barcode recognition result
                            var barcodeRecognitionResult = barcodeRecognitionResults[i];
        
                            // output information about recognized barcode
                            htmlMarkup += '[' + (i + 1) + ':' + barcodeRecognitionResult.barcodeType + ']<br />';
                            htmlMarkup += '  Value: ' + barcodeRecognitionResult.value + '<br />';
                            htmlMarkup += '  Confidence: ' + barcodeRecognitionResult.confidence + '<br />';
                            htmlMarkup += '  Reading quality: ' + barcodeRecognitionResult.readingQuality.toFixed(2) + '<br />';
                            htmlMarkup += '  Threshold: ' + barcodeRecognitionResult.threshold + '<br />';
                            htmlMarkup += '  Region: ' +
                                'LT=(' + barcodeRecognitionResult.region.leftTop.x + ',' + barcodeRecognitionResult.region.leftTop.y + '); ' +
                                'RT=(' + barcodeRecognitionResult.region.rightTop.x + ',' + barcodeRecognitionResult.region.rightTop.y + '); ' +
                                'LB=(' + barcodeRecognitionResult.region.leftBottom.x + ',' + barcodeRecognitionResult.region.leftBottom.y + '); ' +
                                'RB=(' + barcodeRecognitionResult.region.rightBottom.x + ',' + barcodeRecognitionResult.region.rightBottom.y + '); ' +
                                'Angle=' + barcodeRecognitionResult.region.angle.toFixed(1) + '°<br />';
        
                            htmlMarkup += '<br />';
                        }
                    }
        
                    var barcodeInformationElement = document.getElementById("barcodeInformation");
                    barcodeInformationElement.innerHTML = htmlMarkup;
                }
            }
        
            /**
             * Barcode recognition is failed.
             */
            function __readBarcodes_fail(data) {
                // show information about error
                alert(data.errorMessage);
            }
        
        
            // set the session identifier
            Vintasoft.Shared.WebImagingEnviromentJS.set_SessionId("SessionID");
        
            // create HTTP handler that allows to recognize barcodes in image
            var barcodeService = new Vintasoft.Shared.WebServiceHandlerJS("/Handlers/MyVintasoftBarcodeHandler.ashx");
        
            // create the barcode reader
            var barcodeReader = new Vintasoft.Barcode.WebBarcodeReaderJS(barcodeService);
            // specify that Code39 barcode must be searched
            barcodeReader.get_Settings().set_BarcodeType(new Vintasoft.Barcode.WebBarcodeTypeEnumJS("Code39"));
        
            // create web image that references to a file "AllSupportedBarcodes.png" in directory "/UploadedImageFiles/SessionID/"
            var imageSource = new Vintasoft.Shared.WebImageSourceJS("AllSupportedBarcodes.png");
            var image = new Vintasoft.Shared.WebImageJS(imageSource, 0);
        
            // send an asynchronous request for barcode recognition
            barcodeReader.readBarcodes(image, this.__readBarcodes_success, this.__readBarcodes_fail);
        </script>
        
        
    6. Run the ASP.NET WebForms application and see the result.