private object ResolveObject(Type typeToResolve, HashSet <Type> resolvingTypes = null)
{
RegisteredObject registeredObject;
if (!_registeredObjects.TryGetValue(typeToResolve, out registeredObject))
{
if (typeToResolve.IsInterface || typeToResolve.IsAbstract)
{
throw new TypeNotRegisteredException(string.Format(
"The type {0} has not been registered.", typeToResolve.Name));
}
registeredObject = new RegisteredObject(typeToResolve, typeToResolve, LifeCycle.Transient);
}
return(GetInstance(registeredObject, resolvingTypes));
}
private object GetInstance(RegisteredObject registeredObject, HashSet <Type> resolvingTypes = null)
{
if (registeredObject.Instance == null ||
registeredObject.LifeCycle == LifeCycle.Transient)
{
foreach (var constructorInfo in ResolveConstructors(registeredObject))
{
try
{
if (resolvingTypes == null)
{
resolvingTypes = new HashSet <Type> {
registeredObject.TypeToResolve
};
}
else
{
resolvingTypes.Add(registeredObject.TypeToResolve);
}
var parameters = constructorInfo.GetParameters().Select(pi => pi.ParameterType).ToArray();
if (parameters.Any(resolvingTypes.Contains))
{
throw new CyclicDependencyException();
}
registeredObject.CreateInstance(parameters.Select(pi => ResolveObject(pi, resolvingTypes)).ToArray());
}
catch (MissingMethodException)
{
continue;
}
break;
}
if (registeredObject.Instance == null)
{
throw new MissingMethodException();
}
}
if (resolvingTypes != null)
{
resolvingTypes.Remove(registeredObject.TypeToResolve);
}
return(registeredObject.Instance);
}
private IEnumerable <ConstructorInfo> ResolveConstructors(RegisteredObject registeredObject)
{
var constructors = registeredObject.ConcreteType.GetConstructors();
//with DependencyConstructor attribute
var dependencyConstructor =
constructors.FirstOrDefault(
ci => ci.GetCustomAttribute <DependencyConstructorAttribute>() != null);
if (dependencyConstructor != null)
{
yield return(dependencyConstructor);
}
var defaultConstructors = constructors.OrderBy(ci => ci.GetParameters().Count());
if (!defaultConstructors.Any())
{
throw new MissingMethodException();
}
foreach (var constructorInfo in defaultConstructors)
{
yield return(constructorInfo);
}
}
