TdxReportDataSetJSONConnection Class

A component designed to fetch data from one or multiple datasets (TDataSet descendant instances).

Declaration

TdxReportDataSetJSONConnection = class(
    TdxReportCustomInMemoryJSONConnection
)

Remarks

TdxReportDataSetJSONConnection is a data connection component designed to bind a Report Generator (TdxReport) to one or multiple datasets (TdxMemData, TFDTable, TFDQuery, etc.) like any other data-aware VCL control (TcxGrid, for instance).

The TdxReportDataSetJSONConnection component serializes data from associated datasets and stores it in memory in the JSON format^[1] compatible with the DevExpress Reports for Web engine (used as the base for TdxReport).

Main API Members

The list below outlines key members of the TdxReportDataSetJSONConnection class. These members allow you to configure data connection settings.

Data Connection Settings

Active

Specifies if the data connection is active.

AutoRefreshData

Specifies if the data connection component automatically reloads data from associated datasets every time a TdxReport component starts to generate a report for design, preview, and export operations.

DisplayName

Specifies the data connection’s name in both Report Designer and Collection Editor dialogs.

The DisplayName property value is used to refer to the data connection in the report template.

ConnectionString

Provides access to serialized data (in the JSON format) from associated datasets. Use the DataSets property to manage the source dataset collection.

DataSets

Allows you to manage source datasets.

General-Purpose API Members

Collection | Index: Specify the parent collection component.

Code Example: Load and Populate Report Templates from Datasets

This code example loads an XML-based report template (REPX) from a dataset, configures export settings, populates the template with data from another dataset, and displays the report preview:

Delphi
C++

uses
  dxReport,  // Declares the TdxReport component and related types
  dxReport.ConnectionString.JSON.DB;  // Declares the TdxReportDataSetJSONConnection component
// ...

procedure TMyForm.Button1Click(Sender: TObject);
var
  ADataConnection: TdxReportDataSetJSONConnection;
  AReport: TdxReport;
  ALayoutStream: TStream;
begin
  ADataConnection := TdxReportDataSetJSONConnection.Create(Self);
  try
    ADataConnection.Name := 'DataSetJSONData';
    ADataConnection.DataSets.Add('Data', FDataSet);
    AReport := TdxReport.Create(Self);
    try
      AReport.ReportName := 'Report';
      ALayoutStream := FLayoutDataSet.CreateBlobStream(FLayoutDataSet.FieldByName('Layout'), bmRead);
      try
        AReport.Layout.LoadFromStream(ALayoutStream);
      finally
        ALayoutStream.Free;
      end;
      AReport.Language := 'fr-FR';
      AReport.ExportFormats := [TdxReportExportFormat.PDF,
        TdxReportExportFormat.RTF, TdxReportExportFormat.HTML];
      AReport.FilterString := 'id = 5';
      AReport.ShowViewer;
    finally
      AReport.Free;
    end;
  finally
    ADataConnection.Free;
  end;
end;

#include "dxReport.hpp"  // Declares the TdxReport component and related types
#include "dxReport.ConnectionString.JSON.DB.hpp" // Declares the TdxReportDataSetJSONConnection component

// Add the following linker directives to the corresponding CPP source file:
#pragma link "dxReport"  // Required to use dxReport.hpp declarations
#pragma link "dxReport.ConnectionString.JSON.DB" //Required to use TdxReportDataSetJSONConnection declarations
// ...

void __fastcall TMyForm::Button1Click(TObject *Sender)
{
  TdxReportDataSetJSONConnection *ADataConnection;
  TdxReport *AReport;
  TStream *ALayoutStream;
  ADataConnection = new TdxReportDataSetJSONConnection(this);
  try
  {
    ADataConnection->Name = "DataSetJSONData";
    ADataConnection->DataSets->Add("Data", FDataSet);
    AReport = new TdxReport(this);
    try
    {
      AReport->ReportName = "Report";
      ALayoutStream = FLayoutDataSet->CreateBlobStream(FLayoutDataSet->FieldByName("Layout"), bmRead);
      try
      {
        AReport->Layout->LoadFromStream(ALayoutStream);
      }
      __finally
      {
        delete ALayoutStream;
      }
      AReport->Language = "fr-FR";
      AReport->ExportFormats = TdxReportExportFormats() << TdxReportExportFormat::PDF
        << TdxReportExportFormat::RTF << TdxReportExportFormat::HTML;
      AReport->FilterString = "id = 5";
      AReport->ShowViewer();
    }
    __finally
    {
      delete AReport;
    }
  }
  __finally
  {
    delete ADataConnection;
  }
}

Indirect TdxReportDataSetJSONConnection Class References

The following public API members reference the TdxReportDataSetJSONConnection class as a TdxReportCustomDataConnection object:

TdxReportDataConnectionCollection.Add: Creates a data connection of the required type and adds the connection to the collection.
TdxReportDataConnectionCollection.Items: Provides indexed access to all data connection components stored in the collection.
TdxReportDataConnectionManager.Items: Provides indexed access to stored data connection components.

Other Report Data Connection Components

TdxReportInMemoryJSONConnection: A component designed for interaction with data stored in memory.
TdxReportDatabaseSQLConnection: A component designed to fetch data from an SQL database (SQL Server, PostgreSQL, SQLite, etc.).