C++Talk.NET C++ language newsgroups   Archives   FAQ   Search   Memberlist   Usergroups   Register   Profile   Log in to check your private messages   Log in  How to load a class from given class name in a string ?          C++Talk.NET Forum Index -> C++ language (comp.lang.c++) View previous topic :: View next topic   Author Message wow Guest Posted: Fri Feb 27, 2004 5:10 pm    Post subject: How to load a class from given class name in a string ? Hi, Have a problem at hand..... I have a text file as follows: AA : class_a BB : class_b ............ XX : class_x Now my c++ prg should read this file and create objects of the classes in the file at runtime, dynamically. Its not conformed that class_a, class_b,...., class_x are static. I mean the text file can be changed at any time so class_a may be class_aaa later. Thus i cant use if/ switch in my program. If u r going to ask about runtime polimorphism or inheriting all classes with a dummy base class and then use its pointer then it wont work. I m talking about functionality that is provided by CRuntimeClass in MFC, but i have to do the same in c++. Can anyone help??? So finally, i have a string, have to read the string, take it as classname and create object of it. All these at runtime. Thanx in advance... Pravin. Back to top Karl Heinz Buchegger Guest Posted: Fri Feb 27, 2004 6:20 pm    Post subject: Re: How to load a class from given class name in a string ? wow wrote: Quote: Hi, Have a problem at hand..... I have a text file as follows: AA : class_a BB : class_b ........... XX : class_x Now my c++ prg should read this file and create objects of the classes in the file at runtime, dynamically. Its not conformed that class_a, class_b,...., class_x are static. I mean the text file can be changed at any time so class_a may be class_aaa later. Thus i cant use if/ switch in my program. If u r going to ask about runtime polimorphism or inheriting all classes with a dummy base class and then use its pointer then it wont work. I m talking about functionality that is provided by CRuntimeClass in MFC, but i have to do the same in c++. Can anyone help??? So finally, i have a string, have to read the string, take it as classname and create object of it. All these at runtime. In other words: you are looking for the 'factory pattern' Search the web with this keywords and you should find something. -- Karl Heinz Buchegger [email]kbuchegg (AT) gascad (DOT) at[/email] Back to top ak Guest Posted: Sat Feb 28, 2004 8:23 am    Post subject: Re: How to load a class from given class name in a string ? On 27 Feb 2004 09:10:38 -0800, [email]wowpravin (AT) hotmail (DOT) com[/email] (wow) wrote: //So finally, i have a string, have to read the string, take it as //classname and create object of it. All these at runtime. // sounds like COM :) /ak Back to top Sharad Kala Guest Posted: Sat Feb 28, 2004 8:48 am    Post subject: Re: How to load a class from given class name in a string ? "ak com>" <ak@workmail Quote: On 27 Feb 2004 09:10:38 -0800, [email]wowpravin (AT) hotmail (DOT) com[/email] (wow) wrote: //So finally, i have a string, have to read the string, take it as //classname and create object of it. All these at runtime. // sounds like COM This is offtopic but I don't think that's correct. <OT> IIRC, in COM one does not create objects given a string. Given a string/ProgId/CLSID one can load the object(dll/exe) and reach an interface though. </OT> -Sharad Back to top ak Guest Posted: Sun Feb 29, 2004 11:51 am    Post subject: Re: How to load a class from given class name in a string ? On Sat, 28 Feb 2004 14:18:40 +0530, "Sharad Kala" <no.spam_sharadk_ind (AT) yahoo (DOT) com> wrote: // //"ak com>" <ak@workmail //news:lvj0405pugfnh710v6v608cbsrisvo451o (AT) 4ax (DOT) com... //> On 27 Feb 2004 09:10:38 -0800, //> [email]wowpravin (AT) hotmail (DOT) com[/email] (wow) wrote: //> //> //So finally, i have a string, have to read the string, take it as //> //classname and create object of it. All these at runtime. //> // //> //> sounds like COM // //This is offtopic but I don't think that's correct. //<OT> //IIRC, in COM one does not create objects given a string. //Given a string/ProgId/CLSID one can load the object(dll/exe) and reach an //interface though. //</OT> //-Sharad // <OT> its the factory pattern, COM is one example of using the factory pattern. actually yes, the string/progid/clsid/guid are used to load the dll / exe as well as create the objects they implement; manipulating the objects is done via interfaces. </OT> Back to top Display posts from previous: All Posts1 Day7 Days2 Weeks1 Month3 Months6 Months1 Year Oldest FirstNewest First         C++Talk.NET Forum Index -> C++ language (comp.lang.c++) All times are GMT Page 1 of 1   Jump to: Select a forum C/C++----------------C LanguageC Language (Moderated)C++ Language (Moderated)C++ language (comp.lang.c++)C++ language, library and standards Non-English C/C++ Newsgroups----------------C++ (German)C++ (French)  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.