ich habe folgende Definition für TPropInfo für Delphi gefunden:
Code: Alles auswählen
TPropInfo = packed record
PropType: PPTypeInfo;
GetProc: Pointer;
SetProc: Pointer;
StoredProc: Pointer;
Index: Integer;
Default: Integer;
NameIndex: SmallInt;
Name: TSymbolName;
function NameFld: TTypeInfoFieldAccessor; inline;
function Tail: PPropInfo; inline;
end;Ich sehe auch kein Feld, das die Daten eines Feldes einer Klasse aufnimmt.
Wie kann ich da den Inhalt des Datenfeldes (property oder Feldvariable) verändern?
TPropList ist ja ein Array of TPropInfo. Damit sollte ich das jeweilige Feld per Index erreichen. Wie kann ich es aber dann in seinem Inhalt verändern?
Eine Unit, die mir Typinformation anzeigt, habe ich hier, aus Delphi 4 Developer Handbook:
Code: Alles auswählen
unit MainFrm;
interface
uses
Windows, Messages, SysUtils, Classes, Graphics, Controls, Forms, Dialogs,
StdCtrls, ExtCtrls, DBClient, MidasCon, MConnect;
type
TMainForm = class(TForm)
pnlTop: TPanel;
pnlLeft: TPanel;
lbBaseClassInfo: TListBox;
spSplit: TSplitter;
lblBaseClassInfo: TLabel;
pnlRight: TPanel;
lblClassProperties: TLabel;
lbPropList: TListBox;
lbSampClasses: TListBox;
procedure FormCreate(Sender: TObject);
procedure lbSampClassesClick(Sender: TObject);
private
{ Private declarations }
public
{ Public declarations }
end;
var
MainForm: TMainForm;
implementation
uses TypInfo;
{$R *.DFM}
function CreateAClass(const AClassName: string): TObject;
{ This method illustrates how you can create a class from the class name. Note
that this requires that you register the class using RegisterClasses() as
show in the initialization method of this unit. }
var
C : TFormClass;
SomeObject: TObject;
begin
C := TFormClass(FindClass(AClassName));
SomeObject := C.Create(nil);
Result := SomeObject;
end;
procedure GetBaseClassInfo(AClass: TObject; AStrings: TStrings);
{ This method obtains some basic RTTI data from the given object and adds that
information to the AStrings parameter. }
var
ClassTypeInfo: PTypeInfo;
ClassTypeData: PTypeData;
EnumName: String;
begin
ClassTypeInfo := AClass.ClassInfo;
ClassTypeData := GetTypeData(ClassTypeInfo);
with AStrings do
begin
Add(Format('Class Name: %s', [ClassTypeInfo.Name]));
EnumName := GetEnumName(TypeInfo(TTypeKind), Integer(ClassTypeInfo.Kind));
Add(Format('Kind: %s', [EnumName]));
Add(Format('Size: %d', [AClass.InstanceSize]));
Add(Format('Defined in: %s.pas', [ClassTypeData.UnitName]));
Add(Format('Num Properties: %d',[ClassTypeData.PropCount]));
end;
end;
procedure GetClassAncestry(AClass: TObject; AStrings: TStrings);
{ This method retrieves the ancestry of a given object and adds the
class names of the ancestry to the AStrings parameter. }
var
AncestorClass: TClass;
begin
AncestorClass := AClass.ClassParent;
{ Iterate through the Parent classes starting with Sender's
Parent until the end of the ancestry is reached. }
AStrings.Add('Class Ancestry');
while AncestorClass <> nil do
begin
AStrings.Add(Format(' %s',[AncestorClass.ClassName]));
AncestorClass := AncestorClass.ClassParent;
end;
end;
procedure GetClassProperties(AClass: TObject; AStrings: TStrings);
{ This method retrieves the property names and types for the given object
and adds that information to the AStrings parameter. }
var
PropList: PPropList;
ClassTypeInfo: PTypeInfo;
ClassTypeData: PTypeData;
i: integer;
NumProps: Integer;
begin
ClassTypeInfo := AClass.ClassInfo;
ClassTypeData := GetTypeData(ClassTypeInfo);
if ClassTypeData.PropCount <> 0 then
begin
// allocate the memory needed to hold the references to the TPropInfo
// structures on the number of properties.
GetMem(PropList, SizeOf(PPropInfo) * ClassTypeData.PropCount);
try
// fill PropList with the pointer references to the TPropInfo structures
GetPropInfos(AClass.ClassInfo, PropList);
for i := 0 to ClassTypeData.PropCount - 1 do
// filter out properties that are events ( method pointer properties)
if not (PropList[i]^.PropType^.Kind = tkMethod) then
AStrings.Add(Format('%s: %s', [PropList[i]^.Name, PropList[i]^.PropType^.Name]));
// Now get properties that are events (method pointer properties)
NumProps := GetPropList(AClass.ClassInfo, [tkMethod], PropList);
if NumProps <> 0 then begin
AStrings.Add('');
AStrings.Add(' EVENTS ================ ');
AStrings.Add('');
end;
// Fill the AStrings with the events.
for i := 0 to NumProps - 1 do
AStrings.Add(Format('%s: %s', [PropList[i]^.Name, PropList[i]^.PropType^.Name]));
finally
FreeMem(PropList, SizeOf(PPropInfo) * ClassTypeData.PropCount);
end;
end;
end;
procedure TMainForm.FormCreate(Sender: TObject);
begin
// Add some example classes to the list box.
lbSampClasses.Items.Add('TApplication');
lbSampClasses.Items.Add('TButton');
lbSampClasses.Items.Add('TForm');
lbSampClasses.Items.Add('TListBox');
lbSampClasses.Items.Add('TPaintBox');
lbSampClasses.Items.Add('TMidasConnection');
lbSampClasses.Items.Add('TFindDialog');
lbSampClasses.Items.Add('TOpenDialog');
lbSampClasses.Items.Add('TTimer');
lbSampClasses.Items.Add('TComponent');
lbSampClasses.Items.Add('TGraphicControl');
end;
procedure TMainForm.lbSampClassesClick(Sender: TObject);
var
SomeComp: TObject;
begin
lbBaseClassInfo.Items.Clear;
lbPropList.Items.Clear;
// Create an instance of the selected class.
SomeComp := CreateAClass(lbSampClasses.Items[lbSampClasses.ItemIndex]);
try
GetBaseClassInfo(SomeComp, lbBaseClassInfo.Items);
GetClassAncestry(SomeComp, lbBaseClassInfo.Items);
GetClassProperties(SomeComp, lbPropList.Items);
finally
SomeComp.Free;
end;
end;
initialization
begin
RegisterClasses([TApplication, TButton, TForm, TListBox, TPaintBox,
TMidasConnection, TFindDialog, TOpenDialog, TTimer, TComponent,
TGraphicControl]);
end;
end.
[code]
Wie kann ich dann die Feldinhalte verändern, wie das im Objektinspektot der IDE möglich ist?
Verein
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