TRegistryIniFile Class

TRegistryIniFile is a wrapper for the Windows system registry.

Pascal

TRegistryIniFile = class(TCustomIniFile);

C++

class TRegistryIniFile : public TCustomIniFile;

File

Registry

Description

TRegistryIniFile presents a simple interface to the system registry and hides the need to know about the underlying structure of the registry. TRegistryIniFile enables handling the Windows system registry as if it were a Windows 3.x INI file. Instead of processing an INI file, however, TRegistryIniFile reads from and writes to the system registry. Because TRegistryIniFile, like TIniFile, descends from TCustomIniFile, you can use it in common code that writes to both INI files and the registry.

In addition, application developers that are switching from the use of INI files to the system registry can use this object to migrate their application with a minimum of coding changes. By finding all references to TIniFile in an application, replacing them with TRegistryIniFile, and recompiling the application, a developer can update an application to use the system registry instead of INI files without having to code any new logic into the application.

Note: Information contained in existing users' INI files is not migrated into the system registry using the method described above. A one-time operation to explicitly copy the INI file data, through TRegistryIniFile, must be used to do this.

TRegistryIniFile adapts the methods inherited from TCustomIniFile to operate on Registry entries rather than INI file keys. It reinterprets the FileName property as a subkey under the system registry's root key (HKEY_CURRENT_USER by default). What corresponds to a section in an INI file is treated as a key in the system registry, and what corresponds to data entries under a section in an INI file are treated as data values under a key in the system registry.

C++ Examples:

Copy Code

/*
This example demonstrates the usage of Ini files in order to store
and load form configuration between sessions. Example assumes
a RadioGroup and two buttons are present on the main form.
*/
void __fastcall TForm2::btStoreClick(TObject *Sender)
{
    /* Open an instance */
    TCustomIniFile* SettingsFile = OpenIniFileInstance();

    // Store current form properties to be used in later sessions.
    try
    {
        SettingsFile->WriteInteger (Name, "Top", Top);
        SettingsFile->WriteInteger (Name, "Left", Left);
        SettingsFile->WriteInteger (Name, "Width", Width);
        SettingsFile->WriteInteger (Name, "Height", Height);
        SettingsFile->WriteString  (Name, "Caption", Caption);
        SettingsFile->WriteBool    (Name, "InitMax", WindowState == wsMaximized );
    }
    catch(Exception* e)
    {
    }

    delete SettingsFile;
}

void __fastcall TForm2::btLoadClick(TObject *Sender)
{
    /* Open an instance */
    TCustomIniFile* SettingsFile = OpenIniFileInstance();

    try
    {
        /*
        Read all saved values from the last session. The section name
        is the name of the form. Also use form's properties as defaults
        */
        Top     = SettingsFile->ReadInteger(Name, "Top", Top );
        Left    = SettingsFile->ReadInteger(Name, "Left", Left );
        Width   = SettingsFile->ReadInteger(Name, "Width", Width );
        Height  = SettingsFile->ReadInteger(Name, "Height", Height );
        Caption = SettingsFile->ReadString (Name, "Caption", Caption);

        // Load last window state
        if (SettingsFile->ReadBool(Name, "InitMax", WindowState == wsMaximized))
            WindowState = wsMaximized;
        else
            WindowState = wsNormal;
    }
    catch(Exception* e)
    {
    }

    delete SettingsFile;
}

TCustomIniFile* __fastcall TForm2::OpenIniFileInstance()
{
    /*
    Open/create a new INI file that has the same name as our executable
    only with the INI extension.
    */

    switch (RadioGroup1->ItemIndex)
    {
        case 0:
            /* Registry mode selected: in HKEY_CURRENT_USER\Software\... */
            return new TRegistryIniFile(String("Software\\") + Application->Title);
        case 1:
            /* Ini file mode selected */
            return new TIniFile(ChangeFileExt(Application->ExeName, ".INI"));
        case 2:
            /* Memory based Ini file mode selected */
            return new TMemIniFile(ChangeFileExt(Application->ExeName, ".INI"));
      }
}

Delphi Examples:

Copy Code

{
This example demonstrates the use of Ini files in order to store
and load form configurations between sessions. This example requires
a RadioGroup and two buttons.
}
procedure TForm2.btLoadClick(Sender: TObject);
var
  SettingsFile : TCustomIniFile;
begin
  { Open an instance }
  SettingsFile := OpenIniFileInstance();

  try
    {
    Read all saved values from the last session. The section name
    is the name of the form. Also use form's properties as defaults
    }
    Top     := SettingsFile.ReadInteger(Name, 'Top', Top );
    Left    := SettingsFile.ReadInteger(Name, 'Left', Left );
    Width   := SettingsFile.ReadInteger(Name, 'Width', Width );
    Height  := SettingsFile.ReadInteger(Name, 'Height', Height );
    Caption := SettingsFile.ReadString (Name, 'Caption', Caption);

    { Load last window state }
    case SettingsFile.ReadBool(Name, 'InitMax', WindowState = wsMaximized) of
      true : WindowState := wsMaximized;
      false: WindowState := wsNormal;
    end;

  finally
    SettingsFile.Free;
  end;
end;

procedure TForm2.btStoreClick(Sender: TObject);
var
  SettingsFile: TCustomIniFile;
begin
  { Open an instance }
  SettingsFile := OpenIniFileInstance();

  {
  Store current form properties to be used in later sessions.
  }
  try
    SettingsFile.WriteInteger (Name, 'Top', Top);
    SettingsFile.WriteInteger (Name, 'Left', Left);
    SettingsFile.WriteInteger (Name, 'Width', Width);
    SettingsFile.WriteInteger (Name, 'Height', Height);
    SettingsFile.WriteString  (Name, 'Caption', Caption);
    SettingsFile.WriteBool    (Name, 'InitMax', WindowState = wsMaximized );
    SettingsFile.WriteDateTime(Name, 'LastRun', Now);
  finally
    SettingsFile.Free;
  end;

end;

function TForm2.OpenIniFileInstance: TCustomIniFile;
begin
  {
  Open/create a new INI file that has the same name as our executable
  only with the INI extension.
  }

  case RadioGroup1.ItemIndex of
    0:
      begin
        { Registry mode selected: in HKEY_CURRENT_USER\Software\... }
        Result := TRegistryIniFile.Create('Software\' + Application.Title);
      end;
    1:
      begin
        { Ini file mode selected }
        Result := TIniFile.Create(ChangeFileExt(Application.ExeName, '.INI'));
      end;
    2:
      begin
        { Memory based Ini file mode selected }
        Result := TMemIniFile.Create(ChangeFileExt(Application.ExeName, '.INI'));
      end;
  end;
end;