IReportDataSourceHelper.BeforeShowPreview Event

Occurs when the IReportDataSourceHelper.SetupBeforePrint method is executed.

Namespace: DevExpress.ExpressApp.ReportsV2

Assembly: DevExpress.ExpressApp.ReportsV2.v25.1.dll

NuGet Package: DevExpress.ExpressApp.ReportsV2

Declaration

C#

event EventHandler<BeforeShowPreviewEventArgs> BeforeShowPreview

VB.NET

Event BeforeShowPreview As EventHandler(Of BeforeShowPreviewEventArgs)

Event Data

The BeforeShowPreview event's data class is DevExpress.ExpressApp.ReportsV2.BeforeShowPreviewEventArgs.

Remarks

Handle this event to modify the report content before it is displayed. For instance, you can merge two reports immediately before they are displayed. See the following topic for details: How to: Merge the Pages of Two Reports.

The following code snippet uses the BeforeShowPreview event to gain access to a report after it has been generated and to hide unwanted parameters:

using DevExpress.ExpressApp;
using DevExpress.ExpressApp.Actions;
using DevExpress.ExpressApp.ReportsV2;
using DevExpress.Persistent.Base;
using DevExpress.Persistent.BaseImpl;
using YourSolutionName.Module.BusinessObjects;

namespace YourSolutionName.Blazor.Server.Controllers;
public class CustomBlazorController :ViewController {
    public CustomBlazorController() {
        var myAction1 = new SimpleAction(this, "MyBlazorAction1", PredefinedCategory.Edit);
        myAction1.Execute += MyAction1_Execute;
    }

    private void MyAction1_Execute(object sender, SimpleActionExecuteEventArgs e) {
        var reportOsProvider = ReportDataProvider.GetReportObjectSpaceProvider(this.Application.ServiceProvider);
        var reportStorage = ReportDataProvider.GetReportStorage(this.Application.ServiceProvider);

        IObjectSpace objectSpace = reportOsProvider.CreateObjectSpace(typeof(ReportDataV2));
        Contact userReport = (Contact)e.CurrentObject;
        IReportDataV2 reportData = objectSpace.FirstOrDefault<ReportDataV2>(data => data.DisplayName == "test1");
        string handle = reportStorage.GetReportContainerHandle(reportData);
        ReportServiceController controller = Frame.GetController<ReportServiceController>();

        var dataSourceHelper = Application.ServiceProvider.GetRequiredService<IReportDataSourceHelper>();
        dataSourceHelper.BeforeShowPreview += DataSourceHelper_BeforeShowPreview;

        controller.ShowPreview(handle);
        dataSourceHelper.BeforeShowPreview -= DataSourceHelper_BeforeShowPreview;
    }

    private void DataSourceHelper_BeforeShowPreview(object sender, BeforeShowPreviewEventArgs e) {
        var rep = e.Report;
        rep.Parameters[0].Visible = false;
        rep.FilterString = null;
    }
}