public override object Resolve()
{
if (ConstructorInfo == null)
{
throw new InvalidOperationException($"No constructor info for type {InterfaceType.FullName}");
}
// If parameterless, create instance
if (Parameters == null)
{
return(ConstructorInfo.Invoke(null));
}
// If parameters, recursively create parameters instance
object[] parameters = new object[Parameters.Count];
for (int i = 0; i < Parameters.Count; i++)
{
ResolveNodeBase unspecializedParameter = Parameters[i];
object parameterValue = unspecializedParameter.Resolve();
parameters[i] = parameterValue;
}
// and create instance using parameters
return(ConstructorInfo.Invoke(parameters));
}
private ResolveNodeBase InnerBuildResolveTree(Type interfaceType, ICollection <Type> discoveredTypes, List <IParameterValue> userDefinedParameters = null)
{
// Factory ?
Func <object> factory;
if (_factories.TryGetValue(interfaceType, out factory))
{
return new FactoryNode
{
InterfaceType = interfaceType,
Factory = factory
}
}
;
// Instance ?
object instance;
if (_instances.TryGetValue(interfaceType, out instance))
{
return new InstanceNode
{
InterfaceType = interfaceType,
Instance = instance
}
}
;
// Implementation ?
Type implementationType;
if (!_implementations.TryGetValue(interfaceType, out implementationType))
{
return(ErrorNode.TypeNotRegistered);
}
ConstructorInfo[] constructorInfos = implementationType.GetConstructors();
// Valid constructor ?
if (constructorInfos.Length == 0 ||
(constructorInfos.Length == 1 && !constructorInfos[0].IsPublic))
{
return(ErrorNode.NoPublicConstructorOrNoConstructor);
}
// Get parameters for each ctor
var constructorAndParameters = constructorInfos.Select(x => new
{
Constructor = x,
Parameters = x.GetParameters()
}).ToList();
// Get first parameterless if any
var parameterless = constructorAndParameters.FirstOrDefault(x => x.Parameters.Length == 0);
if (parameterless != null)
{
return new BuildableNode
{
InterfaceType = interfaceType,
ConstructorInfo = parameterless.Constructor
}
}
;
// Check if every ctor's parameter is registered in container or resolvable, returns first resolvable
foreach (var c in constructorAndParameters)
{
List <ResolveNodeBase> parametersResolvable = new List <ResolveNodeBase>(c.Parameters.Length);
// Try to resolved every parameters
bool ok = true;
foreach (ParameterInfo parameterInfo in c.Parameters)
{
IParameterValue parameterValue = userDefinedParameters?.FirstOrDefault(x => x.Name == parameterInfo.Name);
if (parameterValue != null)
{
ValueNode parameter = new ValueNode
{
InterfaceType = null,
ParameterValue = parameterValue
};
parametersResolvable.Add(parameter);
}
else
{
if (discoveredTypes.Any(x => x == parameterInfo.ParameterType)) // check cyclic dependency
{
ok = false;
break;
}
discoveredTypes.Add(parameterInfo.ParameterType); // add parameter type to discovered type
ResolveNodeBase parameter = InnerBuildResolveTree(parameterInfo.ParameterType, discoveredTypes, userDefinedParameters);
discoveredTypes.Remove(parameterInfo.ParameterType); // remove parameter type from discovered type
if (parameter is ErrorNode) // once an invalid ctor parameter has been found, try next ctor
{
ok = false;
break;
}
parametersResolvable.Add(parameter);
}
}
if (ok)
{
return new BuildableNode
{
InterfaceType = interfaceType,
ConstructorInfo = c.Constructor,
Parameters = parametersResolvable
}
}
;
}
return(ErrorNode.NoResolvableConstructor);
}
#endregion
}
}