Changing constructor parameter value structure map configuration

Question

I have a scenario similar to this:

public class A
{
    private readonly string _test;

    public A() : this("hello world")
    {

    }

    public A(string test)
    {
        _test = test;
    }
}

public class B
{
    private readonly A _a;

    public B(A a)
    {
        _a = a;
    }
}

Now let's say that I have another class, in this class I am going to inject B but instead this time I want to pass a value for _test in class A

public class MainClass
{
    private readonly B _b;

    public MainClass()
    {
        // this is what I want as an injected result by structure map
        _b = new B(new A("change me"));   
    }
}

so to do this in StructureMap, I have created the following Configuration

var testContainer = new Container(cg =>
            {
                cg.For<A>().Use<A>();

                cg.For<B>().Use<B>().Ctor<A>("a").Is<A>().Ctor<string>("test").Is("change me");

            });

            var tsa = testContainer.GetInstance<A>();
            var tsb = testContainer.GetInstance<B>();

But this doesn't seem to inject the string "change me" to the class A

How can I pass the string to Class A constructor for Class B only?

Evk · Accepted Answer · 2017-12-11 07:56:10Z

2

Your current approach defines two separate constructor parameters to construct type B: one of type A and name "a", and another with type string and name "test". Second one is not present and so is ignored.

Instead, you can do it like this:

cg.For<B>().Use<B>().Ctor<A>().IsSpecial(i => i.Type<A>().Ctor<string>().Is("change me"));

answered Dec 11, 2017 at 7:56

Evk

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1 Comment

Ashish-BeJovial Over a year ago

If your class's constructor has single parameter as "ITaxation" interface instead string than what will be the syntax? same way more than two parameters in same constructor than what will be the syntax?

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