Overview

This package provides an extension for Unity Container that resolves constructor and method default values taking the values via reflection.

Installation

NuGet package is available here.

PM> Install-Package UnityExtras.DefaultParameterValue

Example

Suppose there's a class with several optional constructor parameters:

class ClassA
{
    public ClassA(int x = 34, string s = "qwerty", object obj = null)
    {
        X = x;
        S = s;
        Obj = obj;
    }

    public int X { get; }
    public string S { get; }
    public object Obj { get; }
}

Suppose then, we're going to use the default values when building an instance of this class. Such an intension can be specified per parameter:

var a = new UnityContainer()
    .RegisterType<ClassA>(
        new InjectionConstructor(
            new DefaultParameterValue<int>(),
            new DefaultParameterValue<string>(),
            new DefaultParameterValue<object>()))
    .Resolve<ClassA>();

a.X.ShouldBe(34);
a.S.ShouldBe("qwerty");
a.Obj.ShouldBeNull();

The second option is to use a container extension to resolve all parameter default values, unless explicitly specified:

var obj = new object();
var a = new UnityContainer()
    .AddNewExtension<DefaultParameterValueExtension>()
    .RegisterType<object>()
     .RegisterType<ClassA>(
        new InjectionConstructor(
            new ResolvedParameter<int>(),
            new ResolvedParameter<string>(),
            obj))
    .Resolve<ClassA>();

a.X.ShouldBe(34);
a.S.ShouldBe("qwerty");
a.Obj.ShouldBeSameAs(obj);