Finding Published Properties At Run-time

You can find all the information displayed in the Delphi Object Inspector at runtime, for any *published* property.

The information you need is accessed through the TypInfo unit, you can find an example that does it all in the TWriter.WriteProperties and TWriter.WriteProperty methods of TWriter, defined in Classes.pas.

I've implemented a fully working Delphi-like Object Inspector, so you can be assured that this can be implemented.

If you need source code to help you, I am afraid you will need to further raise the points for this question.

I assume you'd prefer comments first on this one too.

AFAIK you won't find any RTTI documentation in the helpfiles. You need 3rd-party books.

But the code in source\vcl\TypInfo.pas is quite readable, a bit of trying and failing ought to get you going.

Here's some code which'll add property Name, type and value(s) for most (I've skipped a few typekinds) published properties of any object. Just reconstruct the form and step through it. Delphi only generates RTTI for published properties, not public.

Code's tested with D3, it might be somewhat different using D2 but I doubt it.

--
unit Unit1;

interface

uses
  Windows, Messages, SysUtils, Classes, Graphics, Controls, Forms, Dialogs,
  StdCtrls, Grids;

type
  TForm1 = class(TForm)
    Button1: TButton;
    ListBox1: TListBox;
    StringGrid1: TStringGrid;
    procedure Button1Click(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  Form1: TForm1;

implementation
uses
  TypInfo;
 
{$R *.DFM}

function TypeName (PropInfo : PPropInfo) : STRING;
begin
  Result := PropInfo^.PropType^^.Name;
end;

function EnumeratedName (PropInfo : PPropInfo; OrdValue : INTEGER) : STRING;
begin
  Result := GetEnumName(PropInfo^.PropType^, OrdValue);
end;

function SetMemberName (PropInfo : PPropInfo; Index : INTEGER) : STRING;
begin
  Result := GetEnumName(GetTypeData(PropInfo^.PropType^)^.CompType^, Index);
end;


procedure GetPropInfo (AObject : TObject; PropInfo : PPropInfo; AStrings : TStrings);
var
  s, v          : STRING;
  ndx,
  OrdValue      : INTEGER;
  FloatValue    : EXTENDED;
begin


  S := 'Name = '+PropInfo^.Name+
       ', Type = ' + TypeName(PropInfo) +
       ', Value = ';

  case PropInfo^.PropType^^.Kind of
    tkUnknown : v := 'Unknown';
    tkInteger : v := IntToStr(GetOrdProp(AObject, PropInfo));
    tkChar    : v := '#'+IntToStr(GetOrdProp(AObject, PropInfo));
    tkFloat   : v := FloatToStrF(GetFloatProp(AObject, PropInfo), ffFixed, 18, 2);
    tkLString,
    tkString  : v := GetStrProp(AObject, PropInfo);
    tkSet :
      begin
        OrdValue := GetOrdProp(AObject, PropInfo);
        for ndx := 0 to 31 do begin
          if ( (1 shl ndx) and OrdValue) <> 0 then begin
            if v = '' then
              v := SetMemberName(PropInfo, ndx)
            else
              v := v + ', ' + SetMemberName(PropInfo, ndx);
          end;
        end;
        v := '['+v+']';
      end;
    tkEnumeration : v := EnumeratedName (PropInfo, GetOrdProp(AObject, PropInfo));
    tkClass : v := '$'+IntToHex(GetOrdProp(AObject, PropInfo), 8);
  end;
  AStrings.Add(s+v);
end;

procedure GetObjectRTTI (AObject : TObject; AStrings : TStrings);
var
  PropList  : PPropList;
  ndx       : INTEGER;
  PropCount : INTEGER;
begin
  PropCount := GetTypeData(AObject.ClassInfo)^.PropCount;
  GetMem(PropList, PropCount * SizeOf(POINTER));
  GetPropList(AObject.ClassInfo, tkAny, PropList);
  for ndx := 0 to PropCount-1 do
    GetPropInfo (AObject, PropList^[ndx], AStrings);
  FreeMem(PropList);
end;


procedure TForm1.Button1Click(Sender: TObject);
begin
  GetObjectRTTI (StringGrid1, Listbox1.Items);
end;

end.
---

Regards,

Erik.

Humm... ygolan seem to have answered while I was writing...

Erik.

What an excellent answer...

Everyone else I asked (mailing lists, newsgroups) kept saying
"Check out Secrets of Delphi 2".

I'm not usually too keen on buying books...

Anyhow, all I usually need is a good pointer in the right
direction and away I go...typinfo.pas and your code has
helped me...I'm already 30% of the way through my visual
designer...thanks!!!

"Mark a comment as an answer" doesn't work...please post a
short note, sperling, that says "Grade me!".

Thanks for the code.