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ReportingConfigurationBuilder.UseAsyncEngine() Method

Allows you to use asynchronous interfaces and methods.

Namespace: DevExpress.AspNetCore.Reporting

Assembly: DevExpress.AspNetCore.Reporting.v23.1.dll

NuGet Package: DevExpress.AspNetCore.Reporting


public ReportingConfigurationBuilder UseAsyncEngine()


Type Description

A ReportingConfigurationBuilder that can be used to further configure reporting services.


The UseAsyncEngine method turns on asynchronous mode for the Web Document Viewer. It allows the application to access threads from the thread pool while reporting components load, save, or export reports.


In asynchronous mode, you should use asynchronous interfaces and methods with the “Async” postfix instead of their counterparts.

Asynchronous mode does not guarantee that all services will call their asynchronous method implementations. If in your application you call the “synchronous” method counterpart, it may cancel asynchronous process execution, and subsequently reporting services start calling their synchronous method implementations.

To switch to asynchronous mode, call the UseAsyncEngine method at application startup:

using DevExpress.AspNetCore.Reporting;
using Microsoft.Extensions.DependencyInjection;
    public class Startup {
        // ...
        public void ConfigureServices(IServiceCollection services) {
            // ...
            services.ConfigureReportingServices(configurator => {
                // ...
        // ...

If you bind a reporting control to a report model (the WebDocumentViewerModel instance), the reporting engine uses asynchronous API calls. You should generate a report model in the controller and pass the model to the Document Viewer:

using System.Collections.Generic;
using System.ComponentModel.Design;
using System.IO;
using System.Threading.Tasks;
using DevExpress.AspNetCore.Reporting.WebDocumentViewer;
using DevExpress.DataAccess.Sql;
using DevExpress.XtraReports.Services;
using DevExpress.XtraReports.Web.ReportDesigner.Services;
using DevExpress.XtraReports.Web.WebDocumentViewer;
using Microsoft.AspNetCore.Mvc;

namespace ReportingAppAsyncServices.Controllers {
    public class HomeController : Controller
        public IActionResult Index()
            return View();

        public async Task<IActionResult> Designer([FromServices] IReportDesignerModelBuilder reportDesignerModelBuilder, [FromQuery] string reportName = "RootReport")
            var dataSources = new Dictionary<string, object>
                ["Northwind"] = GetNorthwindSqlDataSource()
            var designerModel = await reportDesignerModelBuilder
            return View(designerModel);

        public async Task<IActionResult> Viewer([FromServices] IWebDocumentViewerClientSideModelGenerator modelGenerator, [FromQuery] string reportName = "RootReport")
            var viewerModel = await modelGenerator.GetModelAsync(reportName, WebDocumentViewerController.DefaultUri);
            return View(viewerModel);
        public async Task<IActionResult> ExportToPdf([FromServices] IReportProviderAsync reportProviderAsync, [FromQuery] string reportName = "RootReport")
            var report = await reportProviderAsync.GetReportAsync(reportName, null);
            var reportServiceContainer = (IServiceContainer)report;
            reportServiceContainer.AddService(typeof(IReportProviderAsync), reportProviderAsync);
            using (var stream = new MemoryStream()) {
                await report.CreateDocumentAsync();
                await report.ExportToPdfAsync(stream);
                return File(stream.ToArray(), System.Net.Mime.MediaTypeNames.Application.Pdf);

        SqlDataSource GetNorthwindSqlDataSource()
            // Create a SQL data source with the specified connection string.
            SqlDataSource ds = new SqlDataSource("NWindConnectionString");
            // Create a SQL query to access the Products data table.
            SelectQuery query = SelectQueryFluentBuilder.AddTable("Products").SelectAllColumnsFromTable().Build("Products");
            return ds;

If a reporting control is bound to a report instance or a string (report name), the reporting engine does not use asynchronous methods and interfaces.

View Example: How to Use the Asynchronous Engine for Web Reporting

Asynchronous API

The following table lists interfaces and methods with their asynchronous counterparts:

Report Provider

A report provider creates or retrieves a report object based on the report identifier (report URL). When you implement a custom IReportProviderAsync service, use asynchronous methods. Note that in asynchronous mode, blocking requests use the IReportProvider service instead of the IReportProviderAsync service.

Interface Async Counterpart
IReportProvider IReportProviderAsync

Web Report Storage (ReportStorageWebExtension class)

If your application includes a web report storage, and you wish to use the asynchronous engine, implement the async equivalents of the ReportStorageWebExtension methods. Note that in asynchronous mode, blocking requests use methods without the Async postfix.

Method Async Counterpart
GetData GetDataAsync
none AfterGetDataAsync
GetUrls GetUrlsAsync
SetData SetDataAsync
SetNewData SetNewDataAsync

Report Model

Use async methods in controller actions to create a report model and pass it to the client.

Method Async Counterpart
WebDocumentViewerClientSideModelGenerator.GetModel WebDocumentViewerClientSideModelGenerator.GetModelAsync
ReportDesignerClientSideModelGenerator.GetModel ReportDesignerClientSideModelGenerator.GetModelAsync


Method Async Counterpart
CreateDocument CreateDocumentAsync
ExportToCsv ExportToCsvAsync
ExportToDocx ExportToDocxAsync
ExportToHtml ExportToHtmlAsync
ExportToImage ExportToImageAsync
ExportToMail ExportToMailAsync
ExportToMht ExportToMhtAsync
ExportToPdf ExportToPdfAsync
ExportToRtf ExportToRtfAsync
ExportToText ExportToTextAsync
ExportToXls ExportToXlsAsync
ExportToXlsx ExportToXlsxAsync
Print PrintAsync

JSON Web Token Authentication

Interface Async Counterpart
IWebDocumentViewerExportResultUriGenerator IWebDocumentViewerExportResultUriGeneratorAsync

Report Wizard Customization Service

Method Async Counterpart
CustomizeReportTypeList CustomizeReportTypeListAsync
TryCreateCustomReport TryCreateCustomReportAsync
CustomizeReportOnFinish CustomizeReportOnFinishAsync
See Also