EFOpenError

Hi, I'm using :

function GetTextFromFile(AFile: string; var Returnstring: string): Boolean;
var
  FileStream: TFileStream;
begin
  Result := False;
  if not FileExists(AFile) then Exit;
  FileStream := TFileStream.Create(AFile, fmOpenRead);
  try
    if FileStream.Size <> 0 then
    begin
      SetLength(Returnstring, FileStream.Size);
      FileStream.Read(Returnstring[1], FileStream.Size);
      Result := True;
    end;
  finally
    FileStream.Free;
  end;
end;

Example :

procedure TForm1.Button1Click(Sender: TObject);
begin
GetTextFromFile(FILELISTBOX1.FileName,Edit1.Text);
end;

How to read FILES ON EFOpenError "Cannot open file ..." ?

Thank You.