/// <summary>
/// Instantiate a type with constructor arguments provided directly and/or from an <see cref="IServiceProvider"/>.
/// </summary>
/// <param name="provider">The service provider used to resolve dependencies</param>
/// <param name="instanceType">The type to activate</param>
/// <param name="parameters">Constructor arguments not provided by the <paramref name="provider"/>.</param>
/// <returns>An activated object of type instanceType</returns>
public static object CreateInstance(this IServiceProvider provider, Type instanceType, params object[] parameters)
{
int bestLength = -1;
ConstructorMatcher bestMatcher = default;
if (!instanceType.GetTypeInfo().IsAbstract)
{
foreach (var constructor in instanceType
.GetTypeInfo()
.DeclaredConstructors)
{
if (!constructor.IsStatic && constructor.IsPublic)
{
var matcher = new ConstructorMatcher(constructor);
var length = matcher.Match(parameters);
if (bestLength < length)
{
bestLength = length;
bestMatcher = matcher;
}
}
}
}
if (bestLength == -1)
{
var message = $"A suitable constructor for type '{instanceType}' could not be located. Ensure the type is concrete and services are registered for all parameters of a public constructor.";
throw new InvalidOperationException(message);
}
return(bestMatcher.CreateInstance(provider));
}
public static object CreateInstance(
IServiceProvider provider,
[DynamicallyAccessedMembers(ActivatorAccessibility)] Type instanceType,
params object[] parameters)
{
var bestLength = -1;
ConstructorMatcher bestMatcher = default;
if (!instanceType.IsAbstract)
{
foreach (var constructor in instanceType.GetConstructors())
{
var matcher = new ConstructorMatcher(constructor);
var length = matcher.Match(parameters);
if (bestLength < length)
{
bestLength = length;
bestMatcher = matcher;
}
}
}
if (bestLength == -1)
{
var message = $"A suitable constructor for type '{instanceType}' could not be located. Ensure the type is concrete and services are registered for all parameters of a public constructor.";
throw new InvalidOperationException(message);
}
return(bestMatcher.CreateInstance(provider));
}
public static ObjectFactory CreateObjectFactory(this Type instanceType, params object[] parameters)
{
int bestLength = -1;
var seenPreferred = false;
ConstructorMatcher bestMatcher = default;
if (!instanceType.GetTypeInfo().IsAbstract)
{
foreach (var constructor in instanceType
.GetTypeInfo()
.DeclaredConstructors)
{
if (!constructor.IsStatic && constructor.IsPublic)
{
var matcher = new ConstructorMatcher(constructor);
var isPreferred = constructor.IsDefined(typeof(ActivatorUtilitiesConstructorAttribute), false);
var length = matcher.Match(parameters);
if (isPreferred)
{
if (seenPreferred)
{
ThrowMultipleCtorsMarkedWithAttributeException();
}
if (length == -1)
{
ThrowMarkedCtorDoesNotTakeAllProvidedArguments();
}
}
if (isPreferred || bestLength < length)
{
bestLength = length;
bestMatcher = matcher;
}
seenPreferred |= isPreferred;
}
}
}
if (bestLength == -1)
{
var message = $"A suitable constructor for type '{instanceType}' could not be located. Ensure the type is concrete and services are registered for all parameters of a public constructor.";
throw new InvalidOperationException(message);
}
var parameterTypes = bestMatcher.GetParameterTypes();
return(ActivatorUtilities.CreateFactory(instanceType, parameterTypes));
}
/// <summary>
/// Instantiate a type with constructor arguments provided directly and/or from an <see cref="IServiceProvider"/>.
/// </summary>
/// <param name="provider">The service provider used to resolve dependencies</param>
/// <param name="instanceType">The type to activate</param>
/// <param name="parameters">Constructor arguments not provided by the <paramref name="provider"/>.</param>
/// <returns>An activated object of type instanceType</returns>
public static object CreateInstance(
IServiceProvider provider,
[DynamicallyAccessedMembers(DynamicallyAccessedMemberTypes.PublicConstructors)] Type instanceType,
params object[] parameters)
{
int bestLength = -1;
bool seenPreferred = false;
ConstructorMatcher bestMatcher = default;
if (!instanceType.IsAbstract)
{
foreach (ConstructorInfo?constructor in instanceType.GetConstructors())
{
if (!constructor.IsStatic)
{
var matcher = new ConstructorMatcher(constructor);
bool isPreferred = constructor.IsDefined(typeof(ActivatorUtilitiesConstructorAttribute), false);
int length = matcher.Match(parameters);
if (isPreferred)
{
if (seenPreferred)
{
ThrowMultipleCtorsMarkedWithAttributeException();
}
if (length == -1)
{
ThrowMarkedCtorDoesNotTakeAllProvidedArguments();
}
}
if (isPreferred || bestLength < length)
{
bestLength = length;
bestMatcher = matcher;
}
seenPreferred |= isPreferred;
}
}
}
if (bestLength == -1)
{
string?message = $"A suitable constructor for type '{instanceType}' could not be located. Ensure the type is concrete and services are registered for all parameters of a public constructor.";
throw new InvalidOperationException(message);
}
return(bestMatcher.CreateInstance(provider));
}