Delphi – Read from the log file changed per second

var
 LogFile: TStrings;
 Stream: TStream;
 begin
 LogFile := TStringList.Create;
 try
 Stream := TFileStream.Create(Log, fmOpenRead or fmShareDenyNone);
 try
 LogFile.LoadFromStream(Stream);
 finally
 Stream.Free;< br /> end;

 while LogFile.Count> Memo1.Lines.Count do
 Memo1.Lines.Add(LogFile[Memo1.Lines.Count]);
 finally< br /> LogFile.Free;
 end;
end;

type
 TForm1 = class(TForm )
 //... other stuff added by IDE
 private
 LastLine: Integer;
 end;


// At the point you need to add the logfile to the memo
for i := LastLine to LogFile.Count-1 do
begin
 if ContentWanted(LogFile[i]) then
 Memo1. Lines.Append(LogFile[i]);
 Inc(LastLine);
end;

type
 TForm1 = class(TForm)
 //... IDE stuff here
 private
 FLastLogLine: Integer;
 procedure ProcessLogFile; 
 public
 // Other stuff
 end;

procedure TForm1.ProcessLogFile;
var
 Log: TStringList;
 LogStream : TFileStream;
 i: Integer;
begin
 Lo g := TStringList.Create;
 try
 LogStream := TFileStream.Create(...);
 try
 Log.LoadFromStream(LogStream);
 finally< br /> LogStream.Free;
 end;

 for i := FLastLogLine to Log.Count-1 do
 if Pos('[Globals] []', Log[ i]) <>0 then
 Memo1.Lines.Append(Log[i]);

 // We've now processed all the lines in Log. Save
 / / the last line we processed as the starting point
 // for the next pass.
 FLastLogLine := Log.Count-1; 
 finally
 Log.Free;
 end;
end;

procedure TForm1.Timer1Timer(Sender: TObject);
begin
 Timer1.Enabled := False;
 try
 ProcessLogFile;
 finally
 Timer1.Enabled := True;
 end;
end;
end;

I need to read from a .log file that is constantly changing by another application. (Add more data often)

So I start from the beginning:

< /p>

var
 LogFile: TStrings;
 Stream: TStream;
 begin
 LogFi le := TStringList.Create;
 try
 Stream := TFileStream.Create(Log, fmOpenRead or fmShareDenyNone);
 try
 LogFile.LoadFromStream(Stream);
 finally
 Stream.Free;
 end;

 while LogFile.Count> Memo1.Lines.Count do
 Memo1.Lines.Add(LogFile[Memo1.Lines. Count]);
 finally
 LogFile.Free;
 end;
end;

This is completely fine. It will update in real time while adding data Memo. However, I want to see some added data in the memo. I want to not add these lines, but still can update the memo in real time without the garbage line.

The best way is What?

You obviously need to check if the line contains what you want to include, and only add it when you have it (if you don’t want to include it, Then don’t add it, in either case). It will also be more efficient to track the last line in the LogFile processed before, so you can skip these lines every time-if you set the variable as a private member of the form itself, it will Automatically initialize to 0 when your application starts:

type
 TForm1 = class(TForm)
 //... other stuff added by IDE
 private
 LastLine: Integer;
 end;


// At the point you need to add the logfile to the memo
for i := LastLine to LogFile.Count-1 do
begin
 if ContentWanted(LogFile[i]) then
 Memo1.Lines.Append(LogFile[i]);
 Inc(LastLine);
end;

So handle this problem completely according to your code:

type
 TForm1 = class(TForm)
 //... IDE stuff here
 private
 FLastLogLine: Integer;
 procedure ProcessLogFile;
 public
 // Other stuff
 end;

procedure TForm1.ProcessLogFile;
var
 Log: TStringList;
 LogStream: TFileStream;
 i: Integer;< br />begin
 Log := TStringList.Create;
 try
 LogStream: = TFileStream.Create(...);
 try
 Log.LoadFromStream(LogStream);
 finally
 LogStream.Free;
 end;
< br /> for i := FLastLogLine to Log.Count-1 do
 if Pos('[Globals] []', Log[i]) <>0 then
 Memo1.Lines.Append(Log [i]);

 // We've now processed all the lines in Log. Save
 // the last line we processed as the starting point
 // for the next pass.
 FLastLogLine := Log.Count-1; 
 finally
 Log.Free;
 end;
end;

procedure TForm1.Timer1Timer(Sender: TObject);
begin
 Timer1.Enabled := False;
 try
 ProcessLogFile;
 finally
 Timer1.Enabled := True;
 end;
end;
end;