E/A Error 103 nervt :(

[Rastaman]

Hallo! Folgendes :

Delphi-Quellcode:

unit uMain;

interface

uses
  Windows, Messages, SysUtils, Variants, Classes, Controls, Forms,
  Dialogs, StdCtrls, ComCtrls;

type
  TForm1 = class(TForm)
    Button1: TButton;
    ProgressBar: TProgressBar;
    OpenDialog1: TOpenDialog;
    Button2: TButton;
    Button3: TButton;
    Label1: TLabel;
    SaveDialog1: TSaveDialog;
    Button4: TButton;
    procedure Button4Click(Sender: TObject);
    procedure Button3Click(Sender: TObject);
    procedure Button2Click(Sender: TObject);
    procedure Button1Click(Sender: TObject);
  private
   function copywithprogress(Src, Dest: String): Boolean;
  public
    { Public-Deklarationen }
  end;

var
  Form1: TForm1;
  Stopped: Boolean;

implementation

{$R *.dfm}
{$WARNINGS OFF}

function TForm1.copywithprogress(Src, Dest: String): Boolean;
const
  BufferSize = 102400;  //100 KByte
var
  SizeOfFile, BytesCopied: LongInt;
  Size: Integer;
  Buffer: Array [0..BufferSize] of Byte;
  FInFile, FOutFile: File;
  Time: Cardinal;
  FilePathSource, FilePathDestination: String;
begin
  Result := False;

  if not fileexists(Src) then
  begin
    raise Exception.Create('Source File Doesnt Exist');
    exit;
  end;

  if Src = Dest then
  begin
    raise EInOutError.Create('Source and Destination File are equal');
    exit;
  end;

  Stopped := False;
  Time := GetTickCount;
  AssignFile(FInFile, Src);
  AssignFile(FOutFile, Dest);
  try  //Reset Try BEGIN
    Reset(FInFile,1);
    try  //ReWrite Try BEGIN
      ReWrite(FOutFile,1);
      try
        SizeOfFile := FileSize(FInFile);
        ProgressBar.Max := SizeOfFile;
        ProgressBar.Position := 0;
        BytesCopied := 0;

        FilePathSource := ExtractFilePath(Src);
        FilePathDestination := ExtractFilePath(Dest);
        if Length(FilePathSource) > 20 then
          FilePathSource := Copy(FilePathSource,1,15) + '...';
        if Length(FilePathDestination) > 20 then
          FilePathDestination := Copy(FilePathDestination,1,15) + '...';
        Label1.Caption := 'Von ' + FilePathSource + ' nach ' + FilePathDestination;
        repeat
          if stopped = True then
          begin
            CloseFile(FInFile);
            CloseFile(FOutFile);
            Progressbar.Position := 0;
            Label1.Caption := '';
            Form1.Caption := 'FileCopy';
            if MessageBox(Self.Handle,
                          'Copying Process Stopped. Delete The Destination File?',
                          'Stopped',
                          MB_YESNO
                          or MB_ICONQUESTION) = ID_YES then
              DeleteFile(SaveDialog1.FileName);
            Result := False;
            break;
            Exit;
          end;
          BlockRead(FInFile, Buffer, BufferSize, Size);
          Inc(BytesCopied, Size);
          Form1.Caption := 'MBytes Copied: ' + IntToStr(BytesCopied div 1024 div 1024);
          ProgressBar.Position := BytesCopied;
          BlockWrite(FOutFile, Buffer, Size);
          Application.ProcessMessages;
        until Size < BufferSize;
      finally
        RaiseLastOSError;
      end;
    finally //ReWrite Try Finally
      CloseFile(FOutFile);
    end; //ReWrite Try END
  except  //Reset Try Finally
    CloseFile(FInFile);
  end; //Reset Try END
  Result := True;
  Time := GetTickCount - Time;
  Form1.Caption := Form1.Caption + '  Finished in ' + IntToStr(Time) + ' ms';

end;


procedure TForm1.Button1Click(Sender: TObject);
begin
  Button4.Enabled := True;
  if CopyWithProgress(OpenDialog1.FileName, SaveDialog1.FileName) then
    MessageBox(Self.Handle,
               'Copying Finished',
               'Information',
                MB_ICONINFORMATION);
  Button4.Enabled := False;
end;

procedure TForm1.Button2Click(Sender: TObject);
begin
  if OpenDialog1.Execute then
    SaveDialog1.Filter := StrLower(PChar(ExtractFileExt(OpenDialog1.FileName)));
end;

procedure TForm1.Button3Click(Sender: TObject);
begin
  if OpenDialog1.FileName = '' then
  begin
    MessageBox(Self.Handle,
               'Please Select A Source File First',
               'Information',
               MB_ICONINFORMATION);
    exit;
  end;

  if SaveDialog1.Execute then
   if StrLower(PChar(ExtractFileExt(Savedialog1.FileName))) <> Savedialog1.Filter then
     SaveDialog1.FileName := SaveDialog1.FileName + SaveDialog1.Filter;
end;

procedure TForm1.Button4Click(Sender: TObject);
begin
  Stopped := True;
end;

end.

Klappt Alles, aber wen nich während des Kopierens auf Abbrechen klicke (Button4)
und das dann halt in der Schleife aufgerufen wird, dann kommt die Abfrage, alles gut, aber
dann E/A Error 103. Prog läuft weiter, Datei is je nach JA oder NEIN gelöscht, aber der Fehler nervt halt.
Ausserdem beende ich ja dann mit Exit die procedure --> das Closefile aus dem finally kann eigentlich nicht
mehr aufgerufen werden. Trotzdem 103
Hat einer ne Ahnung worans liegt?