TdxBackendDataSetCollection Class

Declaration

delphi

TdxBackendDataSetCollection = class(
    TcxComponentCollection
)

Remarks

A backend dataset collection manages datasets (TDataSet descendants) for a TdxBackendDataSetJSONConnection component.

Associate a collection item with a dataset (TdxMemData, TFDTable, TFDQuery, etc.) using a TDataSource component (like any other data-aware VCL control, such as TcxGrid).

Main API Members

The list below outlines key members of the TdxBackendDataSetCollection class. These members allow you to manage datasets as data sources for backend client components.

Collection Management APIs

AddCreates a new backend dataset item and adds it to the collection.ClearClears the collection.CountReturns the number of collection items accessible through the Items property.DeleteDeletes individual stored dataset collection items.Items

Provides indexed access to stored dataset collection items.

Tip

Cast the returned object to the TdxBackendDataSetCollectionItem class to access all public API members.

General-Purpose API Members

AssignCopies datasets between collections.BeginUpdate | EndUpdateAllow you to avoid redundant notifications during batch collection changes.

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++

delphi

uses
  dxReport, // Declares the TdxReport component and related types
  dxBackend.ConnectionString.JSON.DataSet; // Declares the TdxBackendDataSetJSONConnection component
// ...

procedure TMyForm.Button1Click(Sender: TObject);
var
  ADataConnection: TdxBackendDataSetJSONConnection;
  AReport: TdxReport;
  ALayoutStream: TStream;
begin
  ADataConnection := TdxBackendDataSetJSONConnection.Create(Self);
  try
    ADataConnection.Name := 'DataSetJSONData';
    ADataConnection.DataSets.Add('Data', FDataSource);
    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;

cpp

#include "dxReport.hpp" // Declares the TdxReport component and related types
#include "dxBackend.ConnectionString.JSON.DataSet.hpp" // Declares the TdxBackendDataSetJSONConnection component

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

void __fastcall TMyForm::Button1Click(TObject *Sender)
{
  TdxBackendDataSetJSONConnection *ADataConnection;
  TdxReport *AReport;
  TStream *ALayoutStream;
  ADataConnection = new TdxBackendDataSetJSONConnection(this);
  try
  {
    ADataConnection->Name = "DataSetJSONData";
    ADataConnection->DataSets->Add("Data", FDataSource);
    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;
  }
}

Direct TdxBackendDataSetCollection Class Reference

The TdxBackendDataSetJSONConnection.DataSets property references a TdxBackendDataSetCollection object.

Inheritance

TObject TPersistent TcxComponentCollection TdxBackendDataSetCollection