How to Sort Sections on TMemIniFile

Question

I am using TMemIniFile to store configuration and I need to sort the sections in alpha order.

For that I have created a descendant of TMemIniFile

  TRWStudioMemIniFile = class(TMemIniFile)
  public
    procedure UpdateFile; override;
    procedure GetSortedStrings(List: TStrings);
  end;


{ TRWStudioMemIniFile }

procedure TRWStudioMemIniFile.GetSortedStrings(List: TStrings);
var
  I, J: Integer;
  Strings: TStrings;
begin
  List.BeginUpdate;
  try
    Sections.Sort;
    for I := 0 to Sections.Count - 1 do
    begin
      List.Add('[' + Sections[I] + ']');
      Strings := TStrings(Sections.Objects[I]);
      for J := 0 to Strings.Count - 1 do List.Add(Strings[J]);
      List.Add('');
    end;
  finally
    List.EndUpdate;
  end;
end;

procedure TRWStudioMemIniFile.UpdateFile;
var
  List: TStringList;
begin
  List := TStringList.Create;
  try
    GetSortedStrings(List);
    List.SaveToFile(FileName, Encoding);
  finally
    List.Free;
  end;
end;

but it needs to have access to the Sections (actually FSections: TStringList, that is a private member of TMemIniFile)

I have created a Helper class to expose that member thru a property. However this behavior is not supported anymore in Delphi 10.1

I started copy/paste the TMemIniFile to my unit and after and endless process I am ending up making a copy of the entire System.IniFile, just to access the FSections.

My question is how to access that FSections member without need to duplicate everything from that unit just to gain visibility

OR is there another way that I can Sort the Sections before saving? (I am just calling the TStringList.Sort from FSections)

Answer 1

Rather than relying on type-casting and "cracking open" the private member, you can instead get the sections into your own TStringList using the inherited ReadSections() method, sort that list as needed, and then use the inherited ReadSectionValues() method to read the strings for each section:

var
  sections: TStringList;
  values: TStringList;
begin
  sections := TStringList.Create;
  try
    ReadSections(sections);
    sections.Sort;

    values := TStringList.Create;
    try
      List.BeginUpdate;
      try
        for I := 0 to sections.Count - 1 do
        begin
          List.Add('[' + sections[I] + ']');

          values.Clear; // Just in case
          ReadSectionValues(sections[i], values);

          for J := 0 to values.Count - 1 do
            List.Add(values[J]);
          List.Add('');
        end;
      finally
        List.EndUpdate;
      end;
    finally
      values.Free;
    end;
  finally
    sections.Free;
  end;
end;