Question

Just want to confirm my understanding is correct. If I use Single instance mode for a service:

[ServiceBehavior(InstanceContextMode=InstanceContextMode.Single)]

and this service calls a class from another asssembly which has a static constructor, that constructor is only called the first time ther service is called? The constructor I am talking about sets up a fair number of AutoMapper maps, and I only want this overhead the first time the service is called.

Taking this further, If I have two different services, and they both us the shared class, am I correct that the static constructor is still only called once?

Best

Ray

Answer 1

There is no connection between InstanceContextMode and how many times static constructor is fired. Static constructor is called once per Application Domain. So if your services are hosted within one Application Domain then your constructor will be called once.
As far as I understand you use the contructor to register AutoMapper configuration… To me it is not a good approach. Assuming your services are hosted on IIS you would better create a Global.asax file and then run you mapping registration code in Application_Start method. Of cource you can wrap it in some static method first.

Hope it helps!