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.NET Forum / ASP.NET / General / April 2008Better Alternative than Application State?
In addition to Web.config, I have a few configuration values that I store in a sql server database. I would like to read them from the database only once per Application.Start (there is no need to read the values per session, as the values are used throughout the entire application and are needed by many pages). Just wondering if Application state would be the best place to store these values. Are there better alternatives for my scenario? I don't think the Cache is a good alternative because items in it can get removed unpredictably, and I need these values to hang around on a permanent basis. Your comments and thoughts are appreciated. Static member(s) will also be appropriate in this scenario. i.e. public static class ConfigStuff { public static readonly int Value1; static ConfigStuff() { // initialize static members with values from database // .... Value1 = 10; } }  SignatureMilosz > In addition to Web.config, I have a few configuration values that I store in > a sql server database. I would like to read them from the database only once [quoted text clipped - 10 lines] > > Your comments and thoughts are appreciated. Your scenario is basically what Application state is for. -- Peter To be a success, arm yourself with the tools you need and learn how to use them. Site: http://www.eggheadcafe.com http://petesbloggerama.blogspot.com http://ittyurl.net > In addition to Web.config, I have a few configuration values that I store in > a sql server database. I would like to read them from the database only once [quoted text clipped - 10 lines] > > Your comments and thoughts are appreciated. I always have a class with static varaibles in my applications for that purpose.... Call it clsGlobal for example. class clsGlobal { public static string _sConnection; public static void Init() { _sConnection = System.Configuration.ConfigurationSettings.AppSettings["ConnectionString"]; } public static string FormatMoney(decimal dTotal) { return dTotal.ToString("$0.00"); } } Application_Start(...) { clsGlobal.Init(); } Then everywere in my application i use clsGlobal._sConnection or something like <%#clsGlobal.FormatMoney(Eval("OrderTotal"))%> Hope you get an idea.... George. > Your scenario is basically what Application state is for. > -- Peter [quoted text clipped - 25 lines] >> >> Your comments and thoughts are appreciated. Hi George, Just a small suggesyion - no need for calling Init method from application start. It enough to use a static constructor. SignatureMilosz > I always have a class with static varaibles in my applications for that > purpose.... [quoted text clipped - 57 lines] > >> > >> Your comments and thoughts are appreciated. I would say it's a novel idea (at least for me). But I would classify it as dangerous. Have you actually tried to use it? Here is an explanation: Are you positive that .NET library is properly initialized at the point when static constructor called? I mean that your System.Configuration.ConfigurationSettings.AppSettings["ConnectionString"]; will actually work correctly. I would imagine that when application is loaded into memory .NET must do a lot of work before this line can be executed... Like load web.config for example. Or even determine that it must be web.config and not executablename.config... And static constructor is executed first thing application is loaded into memory and only then execution point is given to WinMain or whatever it is in ASP.NET world. ------------------------------------------------------------------ I apologize, I hate to be the downer here.... But I would stick with calling it in Application_Start. Nobody wants it's application suddenly stop working (even if it does now) when you switch to new version of .NET PS: I know those problems first hand when I worked on C++ (long time ago) and application would blow up when i called printf in static constructor. Thanks George. > Hi George, > [quoted text clipped - 68 lines] >> >> >> >> Your comments and thoughts are appreciated. Hi George, Hi George, With all respect, i must say you're talking rubbish. I have used "static" approach in .NET many times without any problems, I also come from C++ world but things look different in .NET, let me start from the beginning. .NET static constructor is used to initialize static data members as soon as the class is referenced first time, whereas an instance constructor is used to create an instance of that class with <new> keyword (it is called “lazy initialization”), not as you said "static constructor is executed first thing application is loaded into memory and only then execution point is given to WinMain or whatever it is in ASP.NET world". It is a big difference because it will not be run if you have not used it anywhere. In addition, ConfigurationManager (which is actually called from WebConfigurationManager) uses “lazy initialization” as well meaning it loads the contents of the web config only if it has been requested. As you may expect, ASP.NET gets many things from the web config anyway. Initialization on demand fixes "static initialization order fiasco" in C++, which you pointed out. So don't worry about this issue as it does not exist in C#. King regards Milosz SignatureMilosz > I would say it's a novel idea (at least for me). But I would classify it as > dangerous. Have you actually tried to use it? [quoted text clipped - 96 lines] > >> >> > >> >> Your comments and thoughts are appreciated. I did talked about thing I am not sure about. ".NET static constructor is used to initialize static data members as soon as the class is referenced first time" I did not know that... I just knew that it was not the case in C++ so I kind of assumed C# has the same behavior. That phrase does change it all.... I just did not see those specific in MSDN documentation. -------------------------------------------------------------------------------------------- Wonder how does .NET solves concurrency problem if 2 separate threads access my static clsGlobal._sConnection? Is .NET smart enough to put a lock on the class to run static constructor only once? How does .NET knows that static constructor ran already? Does .NET checks if static constructor ran every time you access the static variable? Seems to me unnecessary performance hit. Thanks George. > Hi George, > [quoted text clipped - 138 lines] >> >> >> >> >> >> Your comments and thoughts are appreciated. Hi George, No probs. I'm not sure how CLR deals with static constructor initialization internally, but i'm sure it is thread safe (i can only guess, but i reckon it is synchronised boolean flag check & static constructor execution, the same as Scott pointed out here http://odetocode.com/Blogs/scott/archive/2004/07/29/360.aspx), and some more details http://bartdesmet.net/blogs/bart/archive/2006/10/30/Answers-to-C_2300_-Quiz-_2D0 0_-Static-constructors-and-type-initialization-.aspx I addition, in my example ConnectionString static property was marked as readonly (which means it can only be initialized in constructor or inline) and set in static constructor which is not lazy init (well, not explicitly, implicitly through lazy static constructor) so it is thread safe, because simply no one can change its value :). Anyway, have a nice weekend. SignatureMilosz > I did talked about thing I am not sure about. > ".NET static constructor is used to initialize static data members as soon [quoted text clipped - 158 lines] > >> >> >> > >> >> >> Your comments and thoughts are appreciated. Good info... Thanks a lot George. > Hi George, > [quoted text clipped - 207 lines] >> >> >> >> >> >> >> >> Your comments and thoughts are appreciated. 1- There's no static constructors on C++ 2 - The std lib does not do any startup initialization (it's all done at compile/link time), so you can call printf on the 1st line of your program without problems. > Hi George, > [quoted text clipped - 68 lines] >> >> >> >> Your comments and thoughts are appreciated. You right, there is no static constructors in C++ I was referring to static class variables. It shows how much I forgot about C++ :) Like in this example: class MyClass { public: int i; MyClass() { i = 40; printf("%d", i); } }; static MyClass obj; void main() { ..... } In this example MyClass() will be called before main(). So if you call printf there it's not considered to be 1st line of your program... 1st line is always main(). May be it was not printf I had problem with but something similar from C++ library. I forgot, last time I used C++ was about 6 years ago. Since then I learned to avoid static initializers. George. > 1- There's no static constructors on C++ > 2 - The std lib does not do any startup initialization (it's all done at > compile/link time), so you can call printf on the 1st line of your program > without problems. Free MagazinesGet these publications absolutely FREE for up to 12 months. There are no hidden fees and no obligation. Simply choose a title, complete the application form and submit it. Read more ...
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