Better Alternative than Application State? -- asp.net

Milosz Skalecki [MCAD]
4/23/2008 4:13:00 PM

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;
}

}

--
Milosz

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Peter Bromberg [C# MVP]
4/24/2008 9:47:01 AM

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

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Milosz Skalecki [MCAD]
4/24/2008 11:41:05 AM

Hi George,

Just a small suggesyion - no need for calling Init method from application
start. It enough to use a static constructor.
--
Milosz

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George Ter-Saakov
4/24/2008 1:04:49 PM

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.

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George Ter-Saakov
4/24/2008 2:53:39 PM

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.

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Milosz Skalecki [MCAD]
4/24/2008 4:27:01 PM

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 â€œlazy
initializationâ€), 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 â€œlazy initializationâ€ 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

--
Milosz

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George Ter-Saakov
4/25/2008 8:56:55 AM

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.

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Milosz Skalecki [MCAD]
4/25/2008 4:05:00 PM

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-_2D00_-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.
--
Milosz

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George Ter-Saakov
4/28/2008 9:02:04 AM

Good info...
Thanks a lot

George.

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jaja
4/28/2008 6:05:47 PM

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.

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George Ter-Saakov
4/29/2008 8:31:58 AM

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.

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