Question

I have a service class which has overloaded constructors. One constructor has 5 parameters and the other has 4.

Before I call,

var service = IoC.Resolve<IService>();

I want to do a test and based on the result of this test, resolve service using a specific constructor. In other words,

        bool testPassed = CheckCertainConditions();
        if (testPassed)
        {
            //Resolve service using 5 paramater constructor
        }
        else
        {
            //Resolve service using 4 parameter constructor
            //If I use 5 parameter constructor under these conditions I will have epic fail.
        }

Is there a way I can specify which one I want to use?

Answer 1

My underlying problem was that I was trying to resolve my class which had the following signature:

public DatabaseSchemaSynchronisationService(IDatabaseService databaseService, IUserSessionManager userSessionManager)

This was basically useless to me because my usersessionmanager had no active NHibernate.ISession because a connection to my database had not yet been made. What I was trying to do was check if I did have a connection and only then resolve this class which served as a service to run database update scripts.

When changing my whole class to perform the scripts in a different way, all I needed in its constructor’s signature was:

public DatabaseSchemaSynchronisationService(ISessionFactory sessionFactory)

This allowed me to open my own session. I did, however have to first check if the connection was ready before attempting to resolve the class, but having IDatabaseSchemaSynchronisationService as a parameter to another class’s constructor; this class also gettting resolved somewhere where I could not check the db connection was a bad idea.

Instead in this second class, I took the IDatabaseSchemaSynchronisationService paramater out of the constructor signature and made it a local variable which only gets instantiated (resolved) :

if (connectionIsReady)

Thanks to everyone who answered.