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RTTI Part 5. Summary.

© Lyapin Ilya

RTTI is undocumented in Delphi 3,Delphi 4, Delphi 5 as well as in any version of C++ Builder. There are two places where you can find information about RTTI - typinfo.pas source file, which is located in X:\delphi\Source\VCL directory and this article. This article contains a complete listing of RTTI types, functions and procedures.

TypeInfo function.

Function TypeInfo(TypeIdent):pointer;
Retrieves a pointer to the RTTI for given type. This function is built into the compiler and does not have actual declaration, but can be used anywhere.

TObject.ClassInfo

class function ClassInfo: Pointer;
Returns a pointer to the RTTI table for the object type. You should use in instead of TypeInfo when RTTI functions are used on objects.

GetTypeData.

function GetTypeData(TypeInfo: PTypeInfo): PTypeData;
GetTypeData retrieves a detailed type information (See TTypeData record). The only argument is a pointer to the type's RTTI information.

E.g.
pIntTypeData:=GetTypeData(typeInfo(integer))
pObjTypeData:=GetTypeData(obj.ClassInfo)

TTypeKind

TTypeKind enumerated type is defined as foolowing:
TTypeKind = (tkUnknown, tkInteger, tkChar, tkEnumeration, tkFloat, tkString, tkSet, tkClass, tkMethod, tkWChar, tkLString, tkWString, tkVariant, tkArray, tkRecord, tkInterface, tkInt64, tkDynArray);
TTypeKinds = set of TTypeKind;

Note that tkInt64 and tkDynArray constants are not included in Delphi 3 There are no corresponding types (Int64 and Dynamic array) in Delphi 3.
TTypeKinds is a set of TTypeKind values.

Enumerated type functions.

function GetEnumName(TypeInfo: PTypeInfo; Value: Integer): string;
function GetEnumValue(TypeInfo: PTypeInfo; const Name: string): Integer;
GetEnumName is used to obtain a string equivalent of enum value, SetEnumValue retrieves ordinal value from the string representation.
The first argument of either function is a pointer to the RTTI for an enumerated type. The second argument is a string or an ordinal correspondingly.
Example:
S:=GetEnumName(TypeInfo(TBitBtnKind),3);
ShowMessage(S); // displays "bkHelp"
I:=GetEnumValue(TypeInfo(TBitBtnKind),s);
ShowMessage(IntToStr(i)); // displays 3

GetPropInfo.

function GetPropInfo(TypeInfo: PTypeInfo; const PropName: string): PPropInfo;
GetPropInfo retrieves a detailed information on the given property. The first argument is a pointer to the RTTI for an object' class. PropName is a string that contains the name of the property.
Delphi 5 also defines an overloaded routine where a kind of the property can be specified:
function GetPropInfo(TypeInfo: PTypeInfo; const PropName: string; TypeKinds: TTypeKinds): PPropInfo;
This function returns nil if the property of given name has other type than specified.
Example:
for i:=0 to ComponentCount-1 do
pPInfo:=GetPropInfo(Components[i].ClassInfo,'Color');
GetPropInfos and GetPropList.
procedure GetPropInfos(TypeInfo: PTypeInfo; PropList: PPropList);
function GetPropList(TypeInfo: PTypeInfo; TypeKinds: TTypeKinds;
PropList: PPropList): Integer;

These routines retrieve the list of an object's propertyes. The first argument is a pointer to the RTTI for an object. PropList is a pointer to an array of PPropInfo records. Application should allocate memory for the array.
I recommend you to write something like following:
Count := GetPropList( Obj.ClassInfo ,tkAll, nil);
PpList := AllocMem( Count * Sizeof ( ppList[0]));