using the MEF to mitigate the #574

Author: dadhi

test/DryIoc.IssuesTests/GHIssue574_Cannot_register_multiple_impls_in_child_container_with_default_service_key.cs

@@ -4,11 +4,21 @@
 using NUnit.Framework;
 using Microsoft.Extensions.DependencyInjection;
 using DryIoc.Microsoft.DependencyInjection;
+using DryIoc.MefAttributedModel;
+using System.ComponentModel.Composition;
 
 namespace DryIoc.IssuesTests
 {
-    public class GHIssue574_Cannot_register_multiple_impls_in_child_container_with_default_service_key
+    // [TestFixture]
+    public class GHIssue574_Cannot_register_multiple_impls_in_child_container_with_default_service_key : ITest
     {
+        public int Run()
+        {
+            // ResolveEnumerableFromChild();
+            ResolveEnumerableFromChild_MefAttributedModel_SupportsMultipleServiceKeys();
+            return 2;
+        }
+
         [Ignore("fixme")]
         public void ResolveEnumerableFromChild()
         {
@@ -23,7 +33,6 @@ public void ResolveEnumerableFromChild()
             var rootContainer = spf.CreateBuilder(new ServiceCollection());
             var childContainer = rootContainer.CreateChild(RegistrySharing.Share, "child-stamp", IfAlreadyRegistered.AppendNewImplementation);
 
-            //childContainer.Populate(services);
             foreach (var service in services)
             {
                 childContainer.RegisterDescriptor(service, IfAlreadyRegistered.AppendNewImplementation, "child-stamp");
@@ -40,14 +49,48 @@ public void ResolveEnumerableFromChild()
                 Is.EqualTo(4));
         }
 
+        // [Test]
+        public void ResolveEnumerableFromChild_MefAttributedModel_SupportsMultipleServiceKeys()
+        {
+            var container = new Container(Rules.MicrosoftDependencyInjectionRules)
+                .WithMef(); // <-- this is the key, LOL ;-)
+
+            var spf = new DryIocServiceProviderFactory(container);
+            var rootContainer = spf.CreateBuilder(new ServiceCollection());
+            var childContainer = rootContainer
+                .CreateChild(RegistrySharing.Share, "child-stamp", IfAlreadyRegistered.AppendNewImplementation);
+
+            // here use RegisterExport instead of the RegisterDescriptor
+            childContainer.RegisterExports(
+                typeof(Printer),
+                typeof(PrinterA),
+                typeof(PrinterB),
+                typeof(NeighborPrinter)
+            );
+
+            var msContainer = childContainer.GetServiceProvider();
+
+            Assert.That(
+                childContainer.Resolve<IEnumerable<IPrinter>>().Count(),
+                Is.EqualTo(msContainer.GetRequiredService<IEnumerable<IPrinter>>().Count()));
+
+            Assert.That(
+                msContainer.GetRequiredService<IEnumerable<IPrinter>>().Count(),
+                Is.EqualTo(4));
+        }
+
         private interface IPrinter { }
 
+        [Export("child-stamp", typeof(IPrinter))]
         private class Printer : IPrinter { }
 
+        [Export("child-stamp", typeof(IPrinter))]
         private class PrinterA : IPrinter { }
 
+        [Export("child-stamp", typeof(IPrinter))]
         private class PrinterB : IPrinter { }
 
+        [Export("child-stamp", typeof(IPrinter))]
         private class NeighborPrinter : IPrinter { }
     }
 }

test/DryIoc.TestRunner/Program.cs

@@ -10,6 +10,7 @@ public static void Main()
         {
             RunAllTests();
 
+            // new GHIssue574_Cannot_register_multiple_impls_in_child_container_with_default_service_key().Run();
             // new GHIssue576_Extension_methods_not_being_handled_correctly_in_MadeOf_service_returning_expression().Run();
             // new GHIssue116_ReOpened_DryIoc_Resolve_with_decorators_goes_wrong_for_parallel_execution().Run();
             // new RequiredPropertiesTests().Run();