Makes Container.CreateInstance into an extension

src/Umbraco.Core/Composing/ContainerExtensions.cs

@@ -2,6 +2,7 @@
 using System.Collections.Concurrent;
 using System.Collections.Generic;
 using System.Linq;
+using System.Reflection;
 
 namespace Umbraco.Core.Composing
 {
@@ -172,5 +173,43 @@ namespace Umbraco.Core.Composing
             // initialize and return the builder
             return container.GetInstance<TBuilder>();
         }
+
+        /// <summary>
+        /// Creates an instance of a service, with arguments.
+        /// </summary>
+        /// <param name="container"></param>
+        /// <param name="type">The type of the instance.</param>
+        /// <param name="args">Named arguments.</param>
+        /// <returns>An instance of the specified type.</returns>
+        /// <remarks>
+        /// <para>The instance type does not need to be registered into the container.</para>
+        /// <para>The arguments are used as dependencies by the container. Other dependencies
+        /// are retrieved from the container.</para>
+        /// </remarks>
+        public static object CreateInstance(this IContainer container, Type type, IDictionary<string, object> args)
+        {
+            // LightInject has this, but then it requires RegisterConstructorDependency etc and has various oddities
+            // including the most annoying one, which is that it does not work on singletons (hard to fix)
+            //return Container.GetInstance(type, args);
+
+            // this method is essentially used to build singleton instances, so it is assumed that it would be
+            // more expensive to build and cache a dynamic method ctor than to simply invoke the ctor, as we do
+            // here - this can be discussed
+
+            var ctor = type.GetConstructors(BindingFlags.Instance | BindingFlags.Public).OrderByDescending(x => x.GetParameters().Length).FirstOrDefault();
+            if (ctor == null) throw new InvalidOperationException($"Could not find a public constructor for type {type.FullName}.");
+
+            var ctorParameters = ctor.GetParameters();
+            var ctorArgs = new object[ctorParameters.Length];
+            var i = 0;
+            foreach (var parameter in ctorParameters)
+            {
+                // no! IsInstanceOfType is not ok here
+                // ReSharper disable once UseMethodIsInstanceOfType
+                var arg = args?.Values.FirstOrDefault(a => parameter.ParameterType.IsAssignableFrom(a.GetType()));
+                ctorArgs[i++] = arg ?? container.GetInstance(parameter.ParameterType);
+            }
+            return ctor.Invoke(ctorArgs);
+        }
     }
 }

src/Umbraco.Core/Composing/IContainer.cs

@@ -1,5 +1,6 @@
 using System;
 using System.Collections.Generic;
+using Umbraco.Core.Composing.LightInject;
 
 namespace Umbraco.Core.Composing
 {
@@ -77,19 +78,6 @@ namespace Umbraco.Core.Composing
         /// <returns>The registrations for the service.</returns>
         IEnumerable<Registration> GetRegistered(Type serviceType);
 
-        /// <summary>
-        /// Creates an instance of a service, with arguments.
-        /// </summary>
-        /// <param name="type">The type of the instance.</param>
-        /// <param name="args">Named arguments.</param>
-        /// <returns>An instance of the specified type.</returns>
-        /// <remarks>
-        /// <para>The instance type does not need to be registered into the container.</para>
-        /// <para>The arguments are used as dependencies by the container. Other dependencies
-        /// are retrieved from the container.</para>
-        /// </remarks>
-        object CreateInstance(Type type, IDictionary<string, object> args);
-
         /// <summary>
         /// Releases an instance.
         /// </summary>

src/Umbraco.Core/Composing/LightInject/LightInjectContainer.cs

@@ -125,33 +125,6 @@ namespace Umbraco.Core.Composing.LightInject
         public IEnumerable<Registration> GetRegistered(Type type)
             => Container.AvailableServices.Where(x => x.ServiceType == type).Select(x => new Registration(x.ServiceType, x.ServiceName));
 
-        /// <inheritdoc />
-        public object CreateInstance(Type type, IDictionary<string, object> args)
-        {
-            // LightInject has this, but then it requires RegisterConstructorDependency etc and has various oddities
-            // including the most annoying one, which is that it does not work on singletons (hard to fix)
-            //return Container.GetInstance(type, args);
-
-            // this method is essentially used to build singleton instances, so it is assumed that it would be
-            // more expensive to build and cache a dynamic method ctor than to simply invoke the ctor, as we do
-            // here - this can be discussed
-
-            var ctor = type.GetConstructors(BindingFlags.Instance | BindingFlags.Public).OrderByDescending(x => x.GetParameters().Length).FirstOrDefault();
-            if (ctor == null) throw new InvalidOperationException($"Could not find a public constructor for type {type.FullName}.");
-
-            var ctorParameters = ctor.GetParameters();
-            var ctorArgs = new object[ctorParameters.Length];
-            var i = 0;
-            foreach (var parameter in ctorParameters)
-            {
-                // no! IsInstanceOfType is not ok here
-                // ReSharper disable once UseMethodIsInstanceOfType
-                var arg = args?.Values.FirstOrDefault(a => parameter.ParameterType.IsAssignableFrom(a.GetType()));
-                ctorArgs[i++] = arg ?? GetInstance(parameter.ParameterType);
-            }
-            return ctor.Invoke(ctorArgs);
-        }
-
         /// <inheritdoc />
         public void Release(object instance)
         {