How to Persist Settings Between Application Runs

• Dec 28, 2020
• 3 minutes to read

The ExpressPrinting System allows you to persist its settings to an INI file, registry, or stream. This topic describes how you can accomplish this automatically between application runs, and how to use a set of specially designed methods to do this manually at arbitrary points in an application.

Persisting Settings Automatically

Information that is automatically persisted by the ExpressPrinting System between application runs includes:

• The position, size, and form layout of the Print Preview dialog (provided that the SaveFormsPosition option is enabled). At design time, the position and size of any dialog windows opened by you are also stored.

• Format settings of component printers.

• PDF export options.

• The root path of file-based explorers.

• Settings of print style managers, including styles and AutoText entries.

Settings other than those listed above should be persisted manually using ExpressPrinting System methods or the TcxPropertiesStore component.

To allow the ExpressPrinting System to automatically preserve its settings, specify the destination storage device and location for the information being stored:

• An INI file. Assign dxstIniFile to the OptionsStoring.StorageType property of the currently active TdxPSEngineController component, and designate the filename via the OptionsStoring.IniFileName property. You can specify the full path to the file in order to store this file to a specific location, other than the application’s starting folder. You can also use a path relative to the application’s starting folder.

For print style managers, you should explicitly specify the AutoSave and StorageName properties to allow them to save their settings to separate files.

• The system registry. Assign dxstRegistry to the OptionsStoring.StorageType property of the currently active engine controller and designate the registry path via the OptionsStoring.RegistryPath property. Values of this property represent the registry keys relative to the HKEY_USERS root key.

Once these properties are set, ExpressPrinting System settings are automatically saved when a dialog window, which corresponds to the settings, is destroyed, and are loaded when the dialog window is created.

Persisting Settings Manually

You can save settings of report links and certain printing components and dialog windows to an INI file or registry at any time, by calling a corresponding method:

• An INI file. Call an object’s SaveToIniFile method.

• The system registry. Call an object’s SaveToRegistry method.

To restore an object’s settings, call its LoadFromIniFile or LoadFromRegistry method.

You can also store settings of component printers and style managers to files or streams and restore them via the SaveToFile, SaveToStream, LoadFromFile, and LoadFromStream methods.

The following code sample demonstrates how to save settings of a component printer and its report links to a specific INI file and then restore from it.

Delphi

var
  AFileName: string;
begin
  AFileName := 'comp_printer_settings.ini';
  dxComponentPrinter1.SaveToIniFile(AFileName);
  ...
  dxComponentPrinter1.LoadFromIniFile(AFileName);
end;

C++

String AFileName = "comp_printer_settings.ini";
  dxComponentPrinter1->SaveToIniFile(AFileName);
  ...
  dxComponentPrinter1->LoadFromIniFile(AFileName);

Note that these methods persist only a few report link properties, including format settings and the report’s start page. If this doesn’t meet your requirements, you can persist all report link settings via a stream’s WriteComponent and ReadComponent methods, as shown in the code sample below.

Delphi

procedure SaveReportLink(AReportLink: TdxGridReportLink; AFileName: string);
var
  AStream: TFileStream;
begin
  AStream := TFileStream.Create(AFileName, fmCreate);
  try
    AStream.WriteComponent(AReportLink);
  finally
    AStream.Free;
  end;
end;
procedure LoadReportLink(AReportLink: TdxGridReportLink; AFileName: string);
var
  AStream: TFileStream;
begin
  AStream := TFileStream.Create(AFileName, fmOpenRead);
  try
    AReportLink.RestoreDefaults;
    AStream.ReadComponent(AReportLink);
  finally
    AStream.Free;
  end;
end;

C++

void __fastcall TForm1::SaveReportLink(TdxGridReportLink *AReportLink, String AFileName)
{
  TFileStream *AStream = new TFileStream(AFileName, fmCreate);
  try {
    AStream->WriteComponent(AReportLink);
  }
  __finally {
    AStream->Free();
  }
}
void __fastcall TForm1::LoadReportLink(TdxGridReportLink *AReportLink, String AFileName);
{
  TFileStream *AStream = new TFileStream(AFileName, fmOpenRead);
  try {
    AReportLink->RestoreDefaults();
    AStream->ReadComponent(AReportLink);
  }
  __finally {
    AStream->Free();
  }
}