How to: Access the Report Preview Control (ASP.NET Core Blazor)

• May 12, 2026
• 2 minutes to read

This example accesses the DxReportViewer component that ASP.NET Core Blazor XAF applications use to display reports.

When a user previews a report, an XAF ASP.NET Core Blazor application opens a Detail View that contains a ReportViewerViewItem. Follow the steps below to access this View Item and its component:

1. Add the Reports V2 Module to your application. For more information, refer to the following topic: Add Reports V2 Module to an Existing XAF Application.
2. Create a Detail View Controller and specify the TargetViewId as ReportsBlazorModuleV2.ReportViewerDetailViewName.

3. Override the OnActivated method and access the Report Viewer’s control as demonstrated in the following code snippet:

   using DevExpress.ExpressApp;
   using DevExpress.ExpressApp.ReportsV2.Blazor;
   using DevExpress.XtraReports;
   
   namespace YourSolutionName.Blazor.Server.Controllers;
   
   public class AccessReportViewerController : ViewController<DetailView> {
   
       public AccessReportViewerController() {
           TargetViewId = ReportsBlazorModuleV2.ReportViewerDetailViewName;
       }
   
       protected override void OnActivated() {
           base.OnActivated();
           View.CustomizeViewItemControl<ReportViewerViewItem>(this, CustomizeReportViewerViewItem);
       }
   
       private void CustomizeReportViewerViewItem(ReportViewerViewItem reportViewerViewItem) {
           //Access the Report Viewer's control.
           IReport report = reportViewerViewItem.ReportViewerModel.Report;
           // ...
       }
   }
   

Customize the Report Viewer Toolbar

Handle the OnCustomizeToolbar event to customize the Report Viewer’s toolbar.

Tip

The ReportViewerModel object allows you to implement any of the techniques described in the following help topic: Customize the Report Viewer Toolbar.

using DevExpress.ExpressApp;
using DevExpress.ExpressApp.ReportsV2.Blazor;
using Microsoft.AspNetCore.Components;
using DevExpress.Blazor.Reporting.Models;

namespace YourSolutionName.Blazor.Server.Controllers;

public class CustomizeReportViewerToolbar : ViewController<DetailView> {
        public CustomizeReportViewerToolbar() {
            TargetViewId = ReportsBlazorModuleV2.ReportViewerDetailViewName;
        }
    protected override void OnActivated() {
        base.OnActivated();
        View.CustomizeViewItemControl<ReportViewerViewItem>(this, CustomizeToolbar);
    }

    private void CustomizeToolbar(ReportViewerViewItem reportViewerViewItem) {
        reportViewerViewItem.ReportViewerModel.OnCustomizeToolbar = EventCallback.Factory.Create<ToolbarModel>(this, (m) => {
            var customToolbarItem = new ToolbarItem() {
                IconCssClass = "message",
                Text = "Show Message",
                Click = (args) => {
                    Application.ShowViewStrategy.ShowMessage("The button has been clicked", InformationType.Success);
                    return Task.CompletedTask;
                }
            };
            m.AllItems.Add(customToolbarItem);
        });
    }
}