Possible to loop only declared properties of a class? - delphi

Question

The extended RTTI has the GetDeclaredProperties function which is exactly what i need, however i faced problems if i use the extended RTTI in multi-threading.
Therefore, i used GetPropList, but this gives me a list of all properties - not only published in the current class (or explicit stated).
i.e.
TBaseSettings = class(TPersistent)
published
property Charset: string read FCharset write FCharset;
end;
TBasicSettings = class(TBaseSettings)
published
property forums: Variant read fforums write fforums;
end;
TConcreteSettings = class(TBasicSettings)
published
property forums; // <-- make it explicit visible: OK
property prefix: Variant read fprefix write fprefix; // <-- OK
end;
I don't want to read the Charset property.
My first guess was to use a modified version of https://stackoverflow.com/a/1565686 to check for inheritance, but actually the forums property is also inherited.
Maybe this is not possible with the classic RTTI? I use Delphi 2010.

Answer 1

In case it's convenient to have your code calling GetDeclaredPropList in a similar way to calling GetPropList, see below.
Edit: I've rewritten the code in Delphi 7 and I believe it should work in Delphi 2010, too (which I don't have at hand).
type
PPropData = ^TPropData;
function AfterString(P: Pointer): Pointer;
begin
Result := Pointer(NativeUInt(P) + (PByte(P)^ + 1));
end;
function GetPropData(TypeData: PTypeData): PPropData;
begin
Result := AfterString(#TypeData^.UnitName);
end;
function NextPropInfo(PropInfo: PPropInfo): PPropInfo;
begin
Result := AfterString(#PropInfo^.Name);
end;
procedure GetDeclaredPropInfos(TypeInfo: PTypeInfo; PropList: PPropList);
var
TypeData: PTypeData;
PropData: PPropData;
PropInfo: PPropInfo;
I: Integer;
begin
TypeData := GetTypeData(TypeInfo);
PropData := GetPropData(TypeData);
FillChar(PropList^, Sizeof(PPropInfo) * PropData^.PropCount, 0);
PropInfo := PPropInfo(#PropData^.PropList);
for I := 0 to PropData^.PropCount - 1 do
begin
PropList^[I] := PropInfo;
PropInfo := NextPropInfo(PropInfo);
end;
end;
function GetDeclaredPropList(TypeInfo: PTypeInfo; out PropList: PPropList): Integer; overload;
begin
Result := GetPropData(GetTypeData(TypeInfo))^.PropCount;
if Result > 0 then
begin
GetMem(PropList, Result * SizeOf(Pointer));
GetDeclaredPropInfos(TypeInfo, PropList);
end;
end;
function GetDeclaredPropList(AObject: TObject; out PropList: PPropList): Integer; overload;
begin
Result := GetDeclaredPropList(PTypeInfo(AObject.ClassInfo), PropList);
end;
// example usage:
var
I, Count: Integer;
PropList: PPropList;
PropInfo: PPropInfo;
begin
Count := GetDeclaredPropList(TypeInfo(TConcreteSettings), PropList);
try
for I := 0 to Count - 1 do
begin
PropInfo := PropList^[I];
Writeln(PropInfo^.Name);
end;
finally
FreeMem(PropList);
end;
end.

Answer 2

var
TypeData: PTypeData;
PropData: PPropData;
PropInfo: PPropInfo;
I: Integer;
begin
TypeData := GetTypeData(TypeInfo(TConcreteSettings));
PropData := GetPropData(TypeData);
if Assigned(PropData) then
begin
PropInfo := #PropData^.PropList;
for I := 0 to PropData^.PropCount - 1 do
begin
Writeln(PropInfo^.Name);
PropInfo := NextPropInfo(PropInfo);
end;
end;
end;
For implementation of GetPropData and NextPropInfo see my other answer above.