Problem with the TPictureList
Hi,
I created a class(TUrunKartiClass) with TPictureList. But when i load pictures to TPictureList class and then try to use it in a function i get an access violation error as described in the code. When i run through the code i get an access violaiton error here : myPicture.Graphic.SaveToSt
What is wrong with this.
Thanks in advance.
I created a class(TUrunKartiClass) with TPictureList. But when i load pictures to TPictureList class and then try to use it in a function i get an access violation error as described in the code. When i run through the code i get an access violaiton error here : myPicture.Graphic.SaveToSt
What is wrong with this.
Thanks in advance.
//THIS IS THE CLASS I HAVE CREATED.
unit UrunKartiClass;
interface
uses Graphics, Contnrs, Classes;
type
TPictureList = Class(TObjectList)
protected
procedure SetResim(I: Integer; APicture: TPicture);
function GetResim(I: Integer): TPicture;
public
function Add(APicture: TPicture): Integer;
property Items[I: Integer]: TPicture read GetResim write SetResim;
End;
TUrunKartiClass = class
private
UrunKodu : String;
UrunAdi : String;
UrunGrubu : String;
Birimi : String;
UrunBoyutlari : String;
Aciklama : String;
EnSonKayitTarihi : String;
published
public
UrunResimleriList : TPictureList;
Constructor Create(
pUrunKodu : String;
pUrunAdi : String;
pUrunGrubu : String;
pBirimi : String;
pUrunBoyutlari : String;
pAciklama : String
);Overload;
Constructor Create(pUrunKodu : String); Overload;
Function Kaydet : Boolean;
Function UrunResimleriniKaydet( pUrunResimleri : array of TPicture) : Boolean;
Function UrunKartiKayitliMi : Boolean;
end;
implementation
uses DatabaseBaglantisi, MSAccess, General, Sysutils, Windows, DB;
Procedure TPictureList.SetResim(I : Integer; APicture : TPicture) ;
begin
inherited Put(I, APicture);
end;
Function TPictureList.GetResim(I : Integer) : TPicture ;
begin
Result := TPicture(inherited Get(I));
end;
Function TPictureList.Add(APicture : TPicture) : Integer ;
begin
Result := inherited Add(APicture);
end;
Constructor TUrunKartiClass.Create(
pUrunKodu : String;
pUrunAdi : String;
pUrunGrubu : String;
pBirimi : String;
pUrunBoyutlari : String;
pAciklama : String);
begin
UrunKodu := pUrunKodu;
UrunAdi := pUrunAdi;
UrunGrubu := pUrunGrubu;
UrunBoyutlari := pUrunBoyutlari;
Aciklama := pAciklama;
end;
Constructor TUrunKartiClass.Create(pUrunKodu : String);
begin
//BU CONSTRUCTOR ILE DATABASE DEN KAYIT BULUNUP OBJECT E ATANACAK.
end;
Function TUrunKartiClass.Kaydet : Boolean;
var TempQuery : TMSQuery;
i : Integer;
TempStream : TMemoryStream;
myPicture : TPicture;
begin
//DEFAULT OLARAK KAYDETMEDI OLARAK VARSAYALIM.
Result := False;
if ConnectToDB then
begin
try
Mouse_Bekleme;
DBConnection.StartTransaction;
//INSERTS UPDATES DELETES COME HERE
try
TempQuery := TMSQuery.Create(TempQuery);
TempQuery.Connection := DBConnection;
TempQuery.SQL.Clear;
TempQuery.Params.Clear;
TempQuery.SQL.Text := 'Insert into Tab_Urun_Kartlari Values(' +
':ProjeGrubu, :ProjeKodu, :UrunKodu, :UrunAdi, :UrunGrubu, :Birimi, ' +
':UrunBoyutlari, :Aciklama, :EnSonKayitTarihi ' +
')';
TempQuery.ParamByName('ProjeGrubu').AsInteger := 1;
TempQuery.ParamByName('ProjeKodu').AsInteger := 1;
TempQuery.ParamByName('UrunKodu').AsString := Trim(UrunKodu);
TempQuery.ParamByName('UrunAdi').AsString := Trim(UrunAdi);
TempQuery.ParamByName('UrunGrubu').AsString := Trim(UrunGrubu);
TempQuery.ParamByName('Birimi').AsString := Trim(Birimi);
TempQuery.ParamByName('UrunBoyutlari').AsString := Trim(UrunBoyutlari);
TempQuery.ParamByName('Aciklama').AsString := Trim(Aciklama);
TempQuery.ParamByName('EnSonKayitTarihi').AsString := EnSonKayitTarihi;
TempQuery.Execute;
MesajGoster(IntToStr(UrunResimleriList.Count), mb_ok);
for i := 0 to UrunResimleriList.Count - 1 do
begin
TempQuery.SQL.Clear;
TempQuery.Params.Clear;
TempQuery.SQL.Text := 'Insert into Tab_Urun_Resimleri Values(' +
':ProjeGrubu, :ProjeKodu, :UrunKodu, :ResimID, :UrunResmi ' +
')';
TempQuery.ParamByName('ProjeGrubu').AsInteger := 1;
TempQuery.ParamByName('ProjeKodu').AsInteger := 1;
TempQuery.ParamByName('UrunKodu').AsString := Trim(UrunKodu);
TempQuery.ParamByName('ResimID').AsInteger := i + 1;
try
//SIMDI ÜRÜN RESIMLERINI KAYDEDELIM.
TempStream := TMemoryStream.create;
TempStream.Position := 0;
myPicture := TPicture.Create;
myPicture := UrunResimleriList.GetResim(i);
MesajGoster(IntToStr(i), mb_ok);
//*************I GET ACCESS VIOLATION ERROR HERE**********
myPicture.Graphic.SaveToStream(TempStream);
TempQuery.ParamByName('UrunResmi').LoadFromStream(TempStream,ftBlob);
TempQuery.Execute;
finally
TempStream.Free;
FreeAndNil(myPicture);
end;
end;
finally
TempQuery.Free;
end;
DBConnection.Commit;
Result := True;
Mouse_Normal;
KaydedildiMesajiGoster;
Except
on E : Exception do
begin
DBConnection.Rollback;
Mouse_Normal;
KaydedilemediMesajiGoster;
MesajGoster2('HATA OLUSTU. LÜTFEN HATAYI NOT ALIP BILGI ISLEME BILDIRINIZ. HATA AÇIKLAMASI = '+E.Message, mb_ok);
Result := False;
end;
end;
DisconnectFromDB;
end else Result := False;
end;
Function TUrunKartiClass.UrunResimleriniKaydet( pUrunResimleri : array of TPicture) : Boolean;
begin
end;
Function TUrunKartiClass.UrunKartiKayitliMi() : Boolean;
begin
end;
end.
// I USE ABOVE CLASS HERE
procedure TfrmUrunTanimlama.btnKaydetClick(Sender: TObject);
var
TempStream: TMemoryStream;
i : Integer;
TempUrunKarti : TUrunKartiClass;
myPicture : TPicture;
begin
TempUrunKarti := TUrunKartiClass.Create(
Trim(txtUrunKodu.Text),
Trim(txtUrunAdi.Text),
Trim(txtUrunGrubu.Text),
Trim(comboBirimi.Text),
Trim(txtUrunBoyutlari.Text),
Trim(memoAciklama.Lines.Text)
);
TempUrunKarti.UrunResimleriList := TPictureList.Create(True);
for i := 0 to cxGrid1View1.DataController.RecordCount - 1 do
begin
try
TempStream := TMemoryStream.Create;
TempStream.Position := 0;
myPicture := TPicture.Create;
cxImage.LoadPicture(myPicture, cxImage.GetGraphicClassByName('TJPEGImage'), cxGrid1View1.DataController.Values[i,cxGrid1View1UrunResimleri.Index]);
myPicture.Graphic.SaveToStream(TempStream);
TempUrunKarti.UrunResimleriList.Add(myPicture);
Finally
TempStream.Free;
// objPicture.Free;
FreeAndNil(myPicture);
end;
end;
MesajGoster(Inttostr(TempUrunKarti.UrunResimleriList.Count), mb_ok);
TempUrunKarti.Kaydet;
TempUrunKarti.Free;
end;
ASKER CERTIFIED SOLUTION
membership
This solution is only available to members.
To access this solution, you must be a member of Experts Exchange.
ASKER
Thanks. I made corrections as you said.
Your biggest errors are that you are creating objects before assigning the variables to others instance in lists. Therefore you are leaking memory. And worse, you destroy those instance while they are still stored in the list. When you try to access to the objects in the list again after that, the memory zone they are pointing to have been released which cause the access violations.