Title: Persistant logfile
Question: I realise this can be achived by opening a file when you open your app and closing it when you end your app
but i carn't be bothered to cut and paste ;-)
Anyway this component is simple and useful for apps that need to create a log file.
Answer:
// *****************************************************************************
// Text file Logging component for Delphi32.
// Copyright 2001, Gavin Uttley. All Rights Reserved.
// This component can be freely used and distributed in commercial and private
// environments, provided this notice is not modified in any way.
//
// *****************************************************************************
// Feel free to contact me if you have any questions, comments or suggestions at
// gav@rootpeg.co.uk
// You can always find the latest version of this component at:
// http://www.rootpeg.co.uk
// if you modify the code please send me a copy with an updated revision history
//
// *****************************************************************************
// Date last modified: 17/08/01
// *****************************************************************************
// TLogit v1.0
// *****************************************************************************
// Description:
// A component that allows application wide persistant log files
// Properties:
// property Active : Boolean;
// property LogName : string;
// property AppendToLog : Boolean;
// property DateTimeStamp : Boolean;
// Procedures:
// procedure WriteMsg(Sender: TObject; Msg: String);
// procedure WriteLogln(Msg: string);
// *****************************************************************************
// Revision History:
// 1.0: Initial release
// *****************************************************************************
unit Logit;
interface
uses SysUtils, Classes;
type
TLogit = class(TComponent)
public
constructor Create(AOwner: TComponent); override;
procedure Free;
private
FLogFile : TextFile;
FActive : Boolean;
FLogName : String;
FAppend : Boolean;
FStamp : Boolean;
procedure WriteLog(s: string); //internal write
procedure SetActive(Value: Boolean);
published
property Active : Boolean read FActive write SetActive default False;
property LogName : string read FLogName write FLogName;
property AppendToLog : Boolean read FAppend write FAppend default True; //Append to log if it exists
property DateTimeStamp: Boolean read FStamp write FStamp default False; //first writes date/time start of ln.
procedure WriteMsg(Sender: TObject; Msg: String); // use this for Callback fired logging events. params must be same.
procedure WriteLogln(Msg: string); // use this for any other writing to the log
end;
procedure Register;
implementation
procedure Register;
begin
RegisterComponents('Misc', [TLogit]);
end;
constructor TLogIt.Create(AOwner: TComponent);
begin
inherited Create(AOwner);
end;
procedure TLogIt.Free;
begin
if FLogName '' then
CloseFile(FLogFile);
end;
procedure TLogIt.SetActive(Value: Boolean);
begin
if Value then begin //if set active to true
if FLogName = '' then //does the log have name?
raise Exception.Create('Log name not set'); //warn user
Assignfile(FLogFile, FLogName); //assign log to filename
if FAppend and (fileexists(FLogName))then //if file exists AND to be appended
Append(FLogFile)
else
Rewrite(FLogFile); //else create file if new or not appended
end;
FActive := Value; //Set Active value
end;
procedure TLogIt.WriteLog(s: String);
begin
if FActive then begin //is the log open?
if FStamp then //do you want a timestamp?
WriteLn(FLogFile, FormatDateTime('dd/mm/yy hh:nn:ss',now) +' '+ s)
else
WriteLn(FLogFile, s);
end else begin
Free; //just in case.
raise Exception.Create('Cannot writeln, Log not open'); //warn user
end;
end;
procedure TLogit.WriteMsg(Sender: TObject; msg:string);
begin
WriteLog(Msg); //use internal write procedure
end;
procedure TLogit.WriteLogln(msg: string);
begin
WriteLog(Msg); //use internal write procedure
end;
end.