How to Use the ConnectionString on Funq.Container?

Question

How can you leverage the connection string property when initializing a registered type with the Funq.Container? ServiceStack shows how to include a connection string while registering a type with the IoC container (Funq.Container) but I cannot find any examples actually using that connection string. I'd like to use this on the client end to specify the base URI for my internal JsonClient.

The examples show this:

container.Register(new MyType(c.Resolve<IDependency>(), connectionString));

But none of the examples show anything ever happening with the connectionString variable.

Answer 1

What that example is saying is the container will create an instance of MyType for each request. When it creates an instance of MyType, the dependency IDependency will be passed as a parameter to the constructor of MyType and so will the connectionString.

Your example code needs an input parameter c though:

container.Register(c => new MyType(c.Resolve<IDependency>(), connectionString));

The usage of the connectionString is up to you. You can use it how you want in your object of MyType. You may wish to expose it as a public property, so it can be accessed. Or use it to alongside you IDependency. By way of an expanded example:

public class MyType
{
    private IDependency _someDependency;
    public string ConnectionString { get; private set }

    public MyType(IDependency dependency, string connectionString)
    {
        _someDependency = dependency.SetConnectionString(connectionString); // Assumes this method exists.
        ConnectionString = connectionString;
    }
}

In your service when MyType is autowired you now have access to the object.

public class MyService : Service
{
    public MyType MyType { get; set; }

    public void Get(SomeRequest request)
    {
         string connectionString = MyType.ConnectionString;
    }
}

If you wish to resolve MyType somewhere else you can use

MyType myType = HostContext.Container.Resolve<MyType>();
string connectionString = myType.ConnectionString;

I hope this clears up that all that is happening is the connectionString is passed into the object constructor and you are free to use it as you require.

Answer 2

Check the docs again. The paragraph directly above the section you referred to shows a delegate method where the object being instantiated requires a connection string. I believe the author is trying to suggest that you could supply the connection string (or any other needed parameters) to the object via the constructor...

container.Register(c => new MyType(c.Resolve<IDependency>(), connectionString));
container.Register<IMyType>(c => new MyType(c.Resolve<IDependency>(), connectionString));
container.Register(c => CreateAndInitialzeMyType(c.Resolve<IDependency1>(), c.Resolve<IDependency2>));

In this example, the method being shown is the class' constructor method... which may require optional parameters.

The doc in question: The IoC container