BorlandTalk.com Borland discussion newsgroups   Archives   FAQ   Search   Memberlist   Usergroups   Register   Profile   Log in to check your private messages   Log in  somethings about Message Handler          BorlandTalk.com Forum Index -> Delphi VCL Components Writing View previous topic :: View next topic   Author Message Pascal Guest Posted: Sun Nov 16, 2003 8:54 am    Post subject: somethings about Message Handler I don't understand somethings about Message Handler, hope anybody would like to answer me: I know I can write the following statement to be a handler for a message, but I don't understand what section is the best section to put it? private or protected is better? procedure WMSIZE(var Message: TCMCancelMode); message WM_SIZE; and in the implement code, should I put 'Inherited' as follow? procedure TMyControl.WMSIZE(var Message: TCMCancelMode); begin inherited; //other codes........... end; Thanks. --Pascal Back to top Mike Lischke Guest Posted: Sun Nov 16, 2003 9:36 am    Post subject: Re: somethings about Message Handler Pascal wrote: Quote: BUT if TMyControl is inherited from TMyParentControl, if I don't use inherited, will it make TParentControl LOSE WMSIZE message or not? Yes, this would happen. Message handler do not have the override keyword, they always are virtual and override ancestor implementations if used in a control. Calling inherited is essential unless you don't want the ancestor to handle the message too or you know for sure, there is no ancestor, which will handle the particular message. Mike -- www.delphi-gems.com www.delphi-unicode.net www.lischke-online.de Back to top Finn Tolderlund Guest Posted: Sun Nov 16, 2003 9:50 am    Post subject: Re: somethings about Message Handler "Pascal" <dontreply (AT) openfind (DOT) com> skrev i en meddelelse news:3fb73b4e (AT) newsgroups (DOT) borland.com... Quote: I know I can write the following statement to be a handler for a message, but I don't understand what section is the best section to put it? private or protected is better? private is fine. Quote: procedure WMSIZE(var Message: TCMCancelMode); message WM_SIZE; and in the implement code, should I put 'Inherited' as follow? procedure TMyControl.WMSIZE(var Message: TCMCancelMode); begin inherited; //other codes........... end; Since you are not overriding a procedure there is no point in using inherited. -- Finn Tolderlund Back to top Pascal Guest Posted: Sun Nov 16, 2003 10:28 am    Post subject: Re: somethings about Message Handler "Finn Tolderlund" <no (AT) spam (DOT) dk> ¼¶¼g©ó¶l¥ó·s»D :3fb74860 (AT) newsgroups (DOT) borland.com... Quote: procedure WMSIZE(var Message: TCMCancelMode); message WM_SIZE; and in the implement code, should I put 'Inherited' as follow? procedure TMyControl.WMSIZE(var Message: TCMCancelMode); begin inherited; //other codes........... end; Since you are not overriding a procedure there is no point in using inherited. -- Finn Tolderlund BUT if TMyControl is inherited from TMyParentControl, if I don't use inherited, will it make TParentControl LOSE WMSIZE message or not? Back to top Peter Below (TeamB) Guest Posted: Sun Nov 16, 2003 10:47 am    Post subject: Re: somethings about Message Handler In article <3fb73b4e (AT) newsgroups (DOT) borland.com>, Pascal wrote: Quote: I know I can write the following statement to be a handler for a message, but I don't understand what section is the best section to put it? private or protected is better? It really does not matter. Inherited in a message handler works differently than for a virtual method. For the latter the ancestors method has to have at least protected visibility, but for message handlers the lookup in the ancestor is not done via the methods name at compile time, but via the message code itself, at run-time. This uses a special table in the class record, the "dynamic message table" (DMT), which associates a message code with a handler methods address. It ignores the visibility specifiers. -- Peter Below (TeamB) Use the newsgroup archives : http://www.mers.com/searchsite.html http://www.tamaracka.com/search.htm http://groups.google.com http://www.prolix.be Back to top Display posts from previous: All Posts1 Day7 Days2 Weeks1 Month3 Months6 Months1 Year Oldest FirstNewest First         BorlandTalk.com Forum Index -> Delphi VCL Components Writing All times are GMT Page 1 of 1   Jump to: Select a forum C++ Builder Newsgroups----------------C++ BuilderC++ Builder (ActiveX)C++ Builder (Announcements)C++ Builder (Command Line Tools)C++ Builder DatabasesC++ Builder Databases (ADO)C++ Builder Databases (Desktop)C++ Builder Databases (InterBase Express)C++ Builder Databases (Multi-Tier)C++ Builder Databases (SQL Servers)C++ Builder (Graphics)C++ Builder (IDE)C++ Builder (Internet)C++ Builder (Internet Socket)C++ Builder (Internet Web)C++ Builder (Jobs)C++ Builder (Language)C++ Builder (Language C++)C++ Builder (Compatibility with MFC)C++ Builder (Native API)C++ Builder (Non-Technical)C++ Builder (Students)C++ Builder (Third Party Tools)C++ Builder (Upgrade)C++ Builder (VCL)C++ Builder (VCL Components Usage)C++ Builder (VCL Components Development)C++ Builder (VCL Usage)C++ Builder (WinAPI)C++ Builder Installation Delphi Newsgroups----------------Delphi (General)Delphi ActiveX Controls UsageDelphi ActiveX Controls DevelopmentDelphi As400Delphi DatabasesDelphi Databases (ADO)Delphi Databases (dbExpress)Delphi Databases (Desktop)Delphi Databases (InterBase Express)Delphi Databases (Multi-Tier)Delphi Databases (SQL Servers)Delphi DeploymentDelphi GraphicsDelphi IDEDelphi InternationalizationDelphi InternetDelphi Internet Isapi-WebBrokerDelphi Internet WebSnapDelphi Internet WinsockDelphi JobsDelphi Language BASMDelphi Language ObjectPascalDelphi Model Driven Architecture (General)Delphi Model Driven Architecture (Third Party)Delphi MultimediaDelphi Native APIDelphi Non-TechnicalDelphi ObjectPascalDelphi OLE AutomationDelphi OO designDelphi OpenToolsAPIDelphi Reporting-ChartingDelphi RTLDelphi StudentsDelphi TeamSourceDelphi Thirdparty ToolsDelphi Thirdparty Tools (General)Delphi Thirdparty Tools (IntraWeb)Delphi Thirdparty Tools (RaveReports)Delphi UpgradeDelphi VCLDelphi VCL ComponentsDelphi VCL Components UsingDelphi VCL Components WritingDelphi WebServices SOAPDelphi WinAPIDelphi XMLDelphi Installationcomp.lang.pascal.delphi.components.misccomp.lang.pascal.delphi.components.usagecomp.lang.pascal.delphi.components.writingcomp.lang.pascal.delphi.databasescomp.lang.pascal.delphi.misccomp.sources.delphi JBuilder Newsgroups----------------JBuilderJBuilder AnnouncementsJBuilder Applet IssuesJBuilder As400JBuilder CompilerJBuilder CORBA/RMIJBuilder DatabasesJBuilder DB SwingJBuilder DebuggerJBuilder DeploymentJBuilder DocumentationJBuilder EnterpriseJBuilder HandheldJBuilder IDEJBuilder JavaJBuilder JavaAPIJBuilder Java LanguageJBuilder Java SwingJBuilder Java BeansJBuilder Java Beans UsageJBuilder Java Beans DevelopmentJBuilder JBCLJBuilder JDataStoreJBuilder JobsJBuilder LinuxJBuilder MacintoshJBuilder & MobileSetJBuilder MultiLingual AppsJBuilder Non-TechnicalJBuilder OpenToolsJBuilder Servlets (JSP)JBuilder StudentsJBuilder Team DevelopmentJBuilder Thirdparty ToolsJBuilder UpgradeJBuilder Installation InterBase Newsgroups----------------InterBaseInterBase Bug DiscussionInterBase GeneralInterBase IBConsoleInterBase OpenSourceInterBase ReplicationInterBase SQLInterBase ThirdpartyInterBase Installation Miscellaneous Borland Newsgroups----------------AppCenterAppServerEnteraVisiBroker  You cannot post new topics in this forum You cannot reply to topics in this forum You cannot edit your posts in this forum You cannot delete your posts in this forum You cannot vote in polls in this forum Powered by phpBB © 2001, 2006 phpBB Group SEO toolkit © 2004-2006 webmedic.