Writing to the Windows Event Log using Delphi -

how can delphi app write windows event log?

what difference between teventlogger , reportevent? how use reportevent function?

if writing windows service , need write local machine's windows event log can call tservice.logmessage mentioned here.

//tmytestservice = class(tservice)  procedure tmytestservice.servicestart(sender: tservice; var started: boolean); begin   logmessage('this error.');   logmessage('this error.', eventlog_error_type);   logmessage('this information.', eventlog_information_type);   logmessage('this warning.', eventlog_warning_type); end; 

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for other type of applications can use svcmgr.teventlogger undocumented helper class tservice write the local machine's windows event log mentioned here, here , here.

uses   svcmgr;  procedure tform1.eventloggerexamplebuttonclick(sender: tobject); begin   teventlogger.create('my test app name')   begin     try       logmessage('this error.');       logmessage('this error.', eventlog_error_type);       logmessage('this information.', eventlog_information_type);       logmessage('this warning.', eventlog_warning_type);           free;     end;   end; end; 

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you can use windows api reportevent function mentioned here , here.

i've created simple class make easier, available on github.

//----------------- example usage: ---------------------------------  uses   eventlog;  procedure tform1.eventlogexamplebuttonclick(sender: tobject); begin   teventlog.source := 'my test app name';    teventlog.writeerror('this error.');   teventlog.writeinfo('this information.');   teventlog.writewarning('this warning.'); end;  //------------------------------------------------------------------  unit eventlog;  interface  type   teventlog = class   private     class procedure checkeventloghandle;     class procedure write(aentrytype: word; aeventid: cardinal; amessage: string); static;   public     class var source: string;     class destructor destroy;      class procedure writeinfo(amessage: string); static;     class procedure writewarning(amessage: string); static;     class procedure writeerror(amessage: string); static;      class procedure addeventsourcetoregistry; static;   end;  threadvar eventloghandle: thandle;  implementation  uses windows, registry, sysutils;  class destructor teventlog.destroy; begin   if eventloghandle > 0   begin     deregistereventsource(eventloghandle);   end; end;  class procedure teventlog.writeinfo(amessage: string); begin   write(eventlog_information_type, 2, amessage); end;  class procedure teventlog.writewarning(amessage: string); begin   write(eventlog_warning_type, 3, amessage); end;  class procedure teventlog.writeerror(amessage: string); begin   write(eventlog_error_type, 4, amessage); end;  class procedure teventlog.checkeventloghandle; begin   if eventloghandle = 0   begin    eventloghandle := registereventsource(nil, pchar(source));   end;   if eventloghandle <= 0   begin     raise exception.create('could not obtain event log handle.');   end; end;  class procedure teventlog.write(aentrytype: word; aeventid: cardinal; amessage: string); begin   checkeventloghandle;   reportevent(eventloghandle, aentrytype, 0, aeventid, nil, 1, 0, @amessage, nil); end;  // requires admin rights. typically called once-off during application's installation class procedure teventlog.addeventsourcetoregistry; var   reg: tregistry; begin   reg := tregistry.create;   try     reg.rootkey := hkey_local_machine;     if reg.openkey('\system\currentcontrolset\services\eventlog\application\' + source, true)     begin       reg.writestring('eventmessagefile', paramstr(0)); // application exe's path       reg.writeinteger('typessupported', 7);       reg.closekey;     end     else     begin       raise exception.create('error updating registry. action requires administrative rights.');     end;       reg.free;   end; end;  initialization  teventlog.source := 'my application name';  end. 

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reportevent supports writing log entry either local or remote machine's event log. remote example see john kaster's edn article.

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note have create message file , register event source otherwise log messages starting this:

the description event id xxx source xxxx cannot found. either component raises event not installed on local computer or installation corrupted. can install or repair component on local computer.

if event originated on computer, display information had saved event.

the following information included event:

1, more information on how create message file see finn tolderlund's tutorial or michael hex's article or can use existing mc , res file included in github project.

2, embed res file application including messagefile.res in dpr file. alternatively can create dll messages.

program mytestapp;  uses   forms,   formmain in 'formmain.pas' {mainform},   eventlog in 'eventlog.pas';  {$r *.res} {$r messagefile\messagefile.res}  begin   application.initialize; 

3, once-off registration requires admin rights writing registry done part of application's installation process.

//for example addeventsourcetoregistry('my application name', paramstr(0)); //or addeventsourcetoregistry('my application name', 'c:\program files\myapp\messages.dll');  //--------------------------------------------------  procedure addeventsourcetoregistry(asource, afilename: string); var   reg: tregistry; begin   reg := tregistry.create;   try     reg.rootkey := hkey_local_machine;     if reg.openkey('\system\currentcontrolset\services\eventlog\application\' + asource, true)     begin       reg.writestring('eventmessagefile', afilename);       reg.writeinteger('typessupported', 7);       reg.closekey;     end     else     begin       raise exception.create('error updating registry. action requires administrative rights.');     end;       reg.free;   end; end; 

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if have need windows event logging , other logging requirements can use logging frameworks such log4d , tracetool

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see here if want write event log window in delphi ide.