Scope of static class constructor and static class fields

Question

I have 2 Console Applications (Console1 and Console2) in one solution. Both applications reference a class library (CL). CL contains a static class (SC) which contains fields that are set per constructor.

My question is if I call the static class within Console1 and the constructor of the SC is called upon first calling any of Console1's containing static methods and fields are set within SC. Now if I run Console2 concurrently, though independently, and also access the SC, what is the precise scope of the static class SC? Will any changes such as calling its constructor that originated from within Console1 have any bearing whatsoever on how the SC behaves when being used in Console2?

No, the second console application will use another instance of that static class. There is no danger — Joseph Devlin, Feb 05 '13 at 11:16

score 3 · Accepted Answer · answered Feb 05 '13 at 11:15

3

The scope is the AppDomain.

Because you have two separate processes, you have two separate AppDomains and two separate "instances" of the static class. There is no state sharing - none at all.

answered Feb 05 '13 at 11:15

Daniel Hilgarth

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Great, answers all my questions. By the way, where can I check in the future, I did not find any reference to the scope when I googled "static classes MSDN", at least I did not see anything on the following page: http://msdn.microsoft.com/en-us/library/79b3xss3.aspx – Matt Feb 05 '13 at 11:20
@Freddy: Well, for one, it is documented on that page you linked: "A static constructor is only called one time, and a static class remains in memory for the lifetime of the *application domain in which your program resides*.". But it is not really highlighted, because it is a fundamental concept that two different processes with the same classes don't share any state. That's not restricted to C#, it is the same in C++, Java etc. – Daniel Hilgarth Feb 05 '13 at 11:25
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Your question may be about static classes but the answers you are getting will all boil down to this: If you run two separate instances of a project the classes used in one instance will not interact with the other. In fact you could run two instances of the same project and you will have no problems. – Joseph Devlin Feb 05 '13 at 11:25
@DanielHilgarth, you are correct, my wrong, missed that. Kazuo, I commented within your own answer. – Matt Feb 05 '13 at 11:33
I marked yours as answer as you were the first to mention AppDomain and the answers are all very similar (probably due to my trivial question ;-) – Matt Feb 05 '13 at 11:36

score 1 · Answer 2 · answered Feb 05 '13 at 11:16

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If Console1 and Console2 are running independently like two completely separate exe files, SC constructor will be called again, else it won't.

answered Feb 05 '13 at 11:16

Uchiha_Sasuke

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score 1 · Answer 3 · answered Feb 05 '13 at 11:17

Console 1 and 2 are running as separate processes. The assemblies are loaded per process (per app domain to be precise), and each will initialize the static constructor and such. Therefore the 'running instances of the assemblies' are completely separate.

score 1 · Answer 4 · answered Feb 05 '13 at 11:29

Your question may be about static classes but the answers you are getting will all boil down to this: If you run two separate instances of a project the classes used in one instance will not interact with the other. In fact you could run two instances of the same project and you will have no problems. It is no different to running two instances of Microsoft word

Scope of static class constructor and static class fields

4 Answers4