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TFileStream

Posted on 2002-06-18
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Last Modified: 2010-05-18
HiCan i read with TFileStream  line by line
(every Line can be in different length)

Example will be wellcome
thank u
Asi
0
Comment
Question by:asi
6 Comments
 
LVL 11

Expert Comment

by:robert_marquardt
ID: 7088977
The easiest way to read a text file is to use a TStringList.

var
  List: TStringList;
begin
  List := TStringList.Create;
  List.LoadFromFile(FileName);
  // do something with the lsit
  List.Free;
end;
0
 

Author Comment

by:asi
ID: 7089401
I need to read a very  big file name.
TStringList is not the way
0
 
LVL 6

Expert Comment

by:edey
ID: 7090054
to do it with a stream you have to read the file char by char until you hit a #10. It's also possible to use a text file. my help (D6) contained this example:

AssignFile, OpenDialog, Readln, CloseFile Example:
var

  F: TextFile;
  S: string;
begin
  if OpenDialog1.Execute then            { Display Open dialog box }
  begin
    AssignFile(F, OpenDialog1.FileName); { File selected in dialog }
    Reset(F);
    Readln(F, S);                        { Read first line of file }
    Edit1.Text := S;                     { Put string in a TEdit control }
    CloseFile(F);
  end;
end;

GL
Mike
0
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LVL 14

Expert Comment

by:DragonSlayer
ID: 7091548
open using FileStream, then load stream data as needed, into TStringStream?
0
 

Accepted Solution

by:
philcm earned 25 total points
ID: 7108132
You'll need to create a command for your filestream!  Ideal thing is to creat a new Object that inherits TFileStream and add the funtion ReadFSLn.  Either way... I've attached code that should help you.  

ReadFSLn will read 1 one and return it has a string. Note that there is 3 things (According to ReadLN in Delphi) that determins a line.  

Hope this help you

//------------------------------------------------------------------------------
//Possible Line Combo  (LF, CR+LF, CR+EOF)
//------------------------------------------------------------------------------
function TForm1.ReadFSLn(FS: TFileStream): String;
var
  Buffer : Char;
  LastChr : Char;
begin
  //Init!
  Result := '';
  Buffer := #0;
  LastChr := #0;
  //Loop till you find the end of a line
  while FS.Position < FS.Size do //Make sure never to pass the EOF
  begin
    FS.Read(Buffer,1);
    Result := Result + Buffer;
    if (Buffer = #10) or ((LastChr = #13) and (Buffer=#10)) or (Buffer=#0) then
      exit; //Line found exit!
    LastChr := Buffer;
  end;
end;


procedure TForm1.Button1Click(Sender: TObject);
var
  FS : TFileStream;
begin
  FS := TFileStream.Create('D:\NewLog.log',fmOpenRead);
  try
    while FS.Position < FS.Size do
      Memo1.Lines.Add( ReadFSLn(FS) );

  finally
    FreeAndNil(FS);
  end;

end;
0
 

Expert Comment

by:junsom
ID: 23677840
thanks so much
0

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