VintaSoft Barcode .NET SDK 15.1: Documentation for Web developer
In This Topic
    Recognize barcodes in image in ASP.NET Core application with Angular
    In This Topic
    This tutorial shows how to create a blank ASP.NET Core Web application in Visual Studio .NET 2022 and recognize barcodes in image in ASP.NET Core application with Angular.

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

      Open Visual Studio .NET 2022 and create a new project, of ASP.NET Core with Angular application type:

      Configure the project to use .NET 8.0:

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

      Add references to the Vintasoft.Barcode.dll, Vintasoft.Barcode.SkiaSharp.dll, Vintasoft.Shared.dll, Vintasoft.Shared.Web.dll, Vintasoft.Barcode.Web.Services.dll and Vintasoft.Barcode.AspNetCore.ApiControllers.dll assemblies from "<InstallPath>\VintaSoft Barcode .NET v15.1\Bin\DotNet8\AnyCPU\" folder in ASP.NET Core Web application.

    3. Server side: Create web service for barcode recognition.

      • Press the right mouse button on the "Controllers" folder and select the "Add => Controller..." menu from context menu
      • Select Empty API controller template, set the controller name to the "MyVintasoftBarcodeApiController" and press the "Add" button
      • Specify that MyVintasoftBarcodeApiController class is derived from Vintasoft.Barcode.AspNetCore.ApiControllers.VintasoftBarcodeApiController class

        Here are source codes of MyVintasoftBarcodeApiController class:
        using Microsoft.AspNetCore.Hosting;
        using Microsoft.AspNetCore.Mvc;
        using Vintasoft.Barcode.AspNetCore.ApiControllers;
        
        namespace WebApplication1.Controllers
        {
            public class MyVintasoftBarcodeApiController : VintasoftBarcodeApiController
            {
        
                public MyVintasoftBarcodeApiController(IWebHostEnvironment hostingEnvironment)
                    : base(hostingEnvironment)
                {
                }
        
            }
        }
        
        
    4. Server side: Add Newtonsoft JSON for deserialization of barcode recognition results.

      Add reference to the Microsoft.AspNetCore.Mvc.NewtonsoftJson nuget-package:


      Open the "Program.cs" file and add code line "services.AddControllersWithViews().AddNewtonsoftJson();". This is necessary for correct deserialization of barcode recognition results.

      Here are source codes of Program.cs:
      var builder = WebApplication.CreateBuilder(args);
      
      // Add services to the container.
      
      builder.Services.AddControllersWithViews().AddNewtonsoftJson();
      builder.Services.AddControllersWithViews();
      
      var app = builder.Build();
      
      // Configure the HTTP request pipeline.
      if (!app.Environment.IsDevelopment())
      {
          // The default HSTS value is 30 days. You may want to change this for production scenarios, see https://aka.ms/aspnetcore-hsts.
          app.UseHsts();
      }
      
      app.UseHttpsRedirection();
      app.UseStaticFiles();
      app.UseRouting();
      
      
      app.MapControllerRoute(
          name: "default",
          pattern: "{controller}/{action=Index}/{id?}");
      
      app.MapFallbackToFile("index.html");
      
      app.Run();
      
      
    5. Compile the project for restoring dependencies using 'npm'.

    6. Client side: Delete files, which are not necessary in this demo.

      Delete directories "ClientApp\src\app\counter\", "ClientApp\src\app\fetch-data\", "ClientApp\src\app\home\", "ClientApp\src\app\nav-menu\" - these Angular components are not necessary in this demo.

      Delete files "WeatherForecast.cs" and "Controllers\WeatherForecastController.cs" - the WeatherForecast Web API controller is not necessary in this demo.


      Open file "ClientApp\src\app\app.component.html" and delete line "<app-nav-menu></app-nav-menu>" from HTML markup - this demo does not need navigation menu.

      Open file "ClientApp\src\app\app.module.ts" and delete code that uses the following Angular components: NavMenuComponent, HomeComponent, CounterComponent, FetchDataComponent - these Angular components are not necessary in this demo.
      Here are source codes of "app.module.ts" file after update:
      import { BrowserModule } from '@angular/platform-browser';
      import { NgModule } from '@angular/core';
      import { FormsModule } from '@angular/forms';
      import { HttpClientModule, HTTP_INTERCEPTORS } from '@angular/common/http';
      import { RouterModule } from '@angular/router';
      
      import { AppComponent } from './app.component';
      
      @NgModule({
        declarations: [
          AppComponent
        ],
        imports: [
          BrowserModule.withServerTransition({ appId: 'ng-cli-universal' }),
          HttpClientModule,
          FormsModule,
          RouterModule.forRoot([
          ])
        ],
        providers: [],
        bootstrap: [AppComponent]
      })
      export class AppModule { }
      
      
    7. Client side: Add JavaScript files and TypeScript modules to the ASP.NET Core Web application.

      Add the "assets" folder to the "ClientApp\src\app\" folder.

      Copy Vintasoft.Shared.js, Vintasoft.Shared.d.ts, Vintasoft.Barcode.js and Vintasoft.Barcode.d.ts files from "<InstallPath>\VintaSoft Barcode .NET v15.1\Bin\JavaScript\" folder to the "ClientApp\src\app\assets\" folder.

      Set "Build Action" to the "TypeScript file" for Vintasoft.Shared.d.ts and Vintasoft.Barcode.d.ts files:


      Add references to Vintasoft JavaScript files to the "projects => Demo => architect => build => options => scripts" section in "ClientApp\angular.json" file:
      ...
      "scripts": [
        "src/app/assets/Vintasoft.Shared.js",
        "src/app/assets/Vintasoft.Barcode.js"
      ]
      ...
      

    8. Client side: Create Angular component that recognizes barcodes in image.

      • Create folder "wwwroot\UploadedImageFiles\SessionID" and copy image file with barcodes "<InstallPath>VintaSoft\Barcode .NET v15.1\Images\AllSupportedBarcodes.png" to the folder. We will recognize barcodes in this image.


        Create folder "ClientApp\src\app\barcode-reader-demo\".


        Create "barcode-reader-demo.component.html" file that will contain HTML markup of Angular component:
        • Select "Add => New Item..." context menu for folder "ClientApp\src\app\barcode-reader-demo\" => "Add new item" dialog will appear
        • Select "HTML Page" type for new item
        • Set "barcode-reader-demo.component.html" as element name
        • Click the "Add" button => dialog will be closed and file "barcode-reader-demo.component.html" will be added into folder "ClientApp\src\app\barcode-reader-demo\"

        Add HTML markup (demo header and image element that will display barcode recognition result) to the "barcode-reader-demo.component.html" file:
        <h1>Angular Barcode Reader Demo</h1>
        
        <div id="barcodeInformation" ></div>
        
        



        Create "barcode-reader-demo.component.ts" file that will contain code of Angular component:
        • Select "Add => New Item..." context menu for folder "ClientApp\src\app\barcode-reader-demo\" => "Add new item" dialog will appear
        • Select "TypeScript File" type for new item
        • Set "barcode-reader-demo.component.ts" as element name
        • Click the "Add" button => dialog will be closed and file "barcode-reader-demo.component.ts" will be added into folder "ClientApp\src\app\barcode-reader-demo\"

        Add TypeScript code to the "barcode-reader-demo.component.cs" file:
        import { Component } from '@angular/core';
        
        @Component({
          selector: 'barcode-reader-demo',
          templateUrl: './barcode-reader-demo.component.html'
        })
        export class BarcodeReaderDemoComponent {
        
          ngOnInit() {
            // set the session identifier
            Vintasoft.Shared.WebImagingEnviromentJS.set_SessionId("SessionID");
        
            // create service that allows to recognize barcodes
            let barcodeService: Vintasoft.Shared.WebServiceControllerJS = new Vintasoft.Shared.WebServiceControllerJS("vintasoft/api/MyVintasoftBarcodeApi");
        
            // create the barcode reader
            let barcodeReader: Vintasoft.Barcode.WebBarcodeReaderJS = 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/"
            let imageSource: Vintasoft.Shared.WebImageSourceJS = new Vintasoft.Shared.WebImageSourceJS("AllSupportedBarcodes.png");
            let image: Vintasoft.Shared.WebImageJS = new Vintasoft.Shared.WebImageJS(imageSource, 0);
        
            // send an asynchronous request for barcode recognition
            barcodeReader.readBarcodes(image, this.__readBarcodes_success, this.__readBarcodes_fail);
          }
        
          /**
           * Barcodes are recognized successfully.
           * @param {object} data Object with information about recognized barcodes.
           */
          private __readBarcodes_success(data: Vintasoft.Barcode.WebBarcodeReadResponseParamsJS) {
            if (data.success) {
              // get the barcode recognition result
              let barcodeRecognitionResults: Vintasoft.Barcode.WebBarcodeRecognitionResultJS[] = data.results;
        
              let htmlMarkup: string = '';
              // 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 (let i: number = 0; i < barcodeRecognitionResults.length; i++) {
                  // get the barcode recognition result
                  let barcodeRecognitionResult: Vintasoft.Barcode.WebBarcodeRecognitionResultJS = 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 />';
                }
              }
        
              let barcodeInformationElement: HTMLDivElement = document.getElementById("barcodeInformation") as HTMLDivElement;
              barcodeInformationElement.innerHTML = htmlMarkup;
            }
          }
        
          /**
           * Barcode recognition is failed.
           * @param {object} data Object with information about error.
           */
          private __readBarcodes_fail(data) {
            // show information about error
            alert(data.errorMessage);
          }
        }
        
        



      • Add created Angular component to the Angular application module - "ClientApp\src\app\app.module.ts" file.
        Here are source codes of "app.module.ts" file after update:
        import { BrowserModule } from '@angular/platform-browser';
        import { NgModule } from '@angular/core';
        import { FormsModule } from '@angular/forms';
        import { HttpClientModule, HTTP_INTERCEPTORS } from '@angular/common/http';
        import { RouterModule } from '@angular/router';
        
        import { AppComponent } from './app.component';
        import { BarcodeReaderDemoComponent } from './barcode-reader-demo/barcode-reader-demo.component';
        
        @NgModule({
          declarations: [
            AppComponent,
            BarcodeReaderDemoComponent
          ],
          imports: [
            BrowserModule.withServerTransition({ appId: 'ng-cli-universal' }),
            HttpClientModule,
            FormsModule,
            RouterModule.forRoot([
              { path: '', component: BarcodeReaderDemoComponent, pathMatch: 'full' },
            ])
          ],
          providers: [],
          bootstrap: [AppComponent]
        })
        export class AppModule { }
        
        

    9. Run the ASP.NET Core Web application with Angular and see the result.