Object2Object mapping enhancements.

framework/src/Volo.Abp.ObjectMapping/Volo/Abp/ObjectMapping/DefaultObjectMapper.cs

@@ -1,6 +1,13 @@
 using Microsoft.Extensions.DependencyInjection;
 using System;
+using System.Collections;
+using System.Collections.Concurrent;
+using System.Collections.Generic;
+using System.Collections.ObjectModel;
+using System.Linq;
+using System.Reflection;
 using Volo.Abp.DependencyInjection;
+using Volo.Abp.Reflection;
 
 namespace Volo.Abp.ObjectMapping;
 
@@ -19,6 +26,8 @@ public class DefaultObjectMapper<TContext> : DefaultObjectMapper, IObjectMapper<
 
 public class DefaultObjectMapper : IObjectMapper, ITransientDependency
 {
+    protected static ConcurrentDictionary<string, MethodInfo> MethodInfoCache { get; } = new ConcurrentDictionary<string, MethodInfo>();
+
     public IAutoObjectMappingProvider AutoObjectMappingProvider { get; }
     protected IServiceProvider ServiceProvider { get; }
 
@@ -46,6 +55,12 @@ public class DefaultObjectMapper : IObjectMapper, ITransientDependency
             {
                 return specificMapper.Map(source);
             }
+
+            var result = TryToMapCollection<TSource, TDestination>(scope, source, default);
+            if (result != null)
+            {
+                return result;
+            }
         }
 
         if (source is IMapTo<TDestination> mapperSource)
@@ -85,6 +100,12 @@ public class DefaultObjectMapper : IObjectMapper, ITransientDependency
             {
                 return specificMapper.Map(source, destination);
             }
+
+            var result = TryToMapCollection(scope, source, destination);
+            if (result != null)
+            {
+                return result;
+            }
         }
 
         if (source is IMapTo<TDestination> mapperSource)
@@ -102,6 +123,37 @@ public class DefaultObjectMapper : IObjectMapper, ITransientDependency
         return AutoMap(source, destination);
     }
 
+    protected virtual TDestination? TryToMapCollection<TSource, TDestination>(IServiceScope serviceScope, TSource source, TDestination? destination)
+    {
+        if (!typeof(TSource).IsGenericType || typeof(TSource).GetGenericTypeDefinition() != typeof(ICollection<>) ||
+            !typeof(TDestination).IsGenericType || typeof(TDestination).GetGenericTypeDefinition() != typeof(ICollection<>))
+        {
+            //skip, not a collection
+            return default;
+        }
+
+        var sourceGenericTypeDefinition = typeof(TSource).GenericTypeArguments[0];
+        var destinationGenericTypeDefinition = typeof(TDestination).GenericTypeArguments[0];
+        var specificGenericTypeDefinitionMapper = serviceScope.ServiceProvider.GetService(typeof(IObjectMapper<,>).MakeGenericType(sourceGenericTypeDefinition, destinationGenericTypeDefinition));
+        if (specificGenericTypeDefinitionMapper == null)
+        {
+            //skip, no specific mapper
+            return default;
+        }
+
+        var cacheKey = $"{specificGenericTypeDefinitionMapper.GetType().FullName}-{(destination == null ? "MapMethodWithSingleParameter" : "MapMethodWithDoubleParameters")}";
+        var method = MethodInfoCache.GetOrAdd(cacheKey, x => specificGenericTypeDefinitionMapper.GetType().GetMethods().First(m => m.Name == nameof(IObjectMapper<object, object>.Map) && m.GetParameters().Length == (destination == null ? 1 : 2)));
+        var result = Activator.CreateInstance(typeof(Collection<>).MakeGenericType(destinationGenericTypeDefinition))!.As<IList>();
+        foreach (var sourceItem in (IEnumerable)source!)
+        {
+            result.Add(destination == null
+                ? method.Invoke(specificGenericTypeDefinitionMapper, new [] {sourceItem})!
+                : method.Invoke(specificGenericTypeDefinitionMapper, new [] {sourceItem, Activator.CreateInstance(destinationGenericTypeDefinition)!})!);
+        }
+
+        return (TDestination)result!;
+    }
+
     protected virtual TDestination AutoMap<TSource, TDestination>(object source)
     {
         return AutoObjectMappingProvider.Map<TSource, TDestination>(source);

framework/test/Volo.Abp.AutoMapper.Tests/Volo/Abp/AutoMapper/AbpAutoMapperModule_Specific_ObjectMapper_Tests.cs

@@ -1,4 +1,6 @@
 using System;
+using System.Collections.Generic;
+using System.Linq;
 using Microsoft.Extensions.DependencyInjection;
 using Shouldly;
 using Volo.Abp.AutoMapper.SampleClasses;
@@ -24,6 +26,25 @@ public class AbpAutoMapperModule_Specific_ObjectMapper_Tests : AbpIntegratedTest
         dto.Number.ShouldBe(43); //MyEntityToMyEntityDto2Mapper adds 1 to number of the source.
     }
 
+    [Fact]
+    public void Specific_Object_Mapper_Should_Be_Used_For_Collections_If_Registered()
+    {
+        var dtos = _objectMapper.Map<ICollection<MyEntity>, ICollection<MyEntityDto2>>(new List<MyEntity>()
+        {
+            new MyEntity { Number = 42 }
+        });
+        dtos.First().Number.ShouldBe(43); //MyEntityToMyEntityDto2Mapper adds 1 to number of the source.
+
+        dtos = _objectMapper.Map<ICollection<MyEntity>, ICollection<MyEntityDto2>>(new List<MyEntity>()
+        {
+            new MyEntity { Number = 42 }
+        }, new List<MyEntityDto2>() //When mapping to an existing collection, the destination collection is cleared first
+        {
+            new MyEntityDto2 { Number = 44 }
+        });
+        dtos.First().Number.ShouldBe(43); //MyEntityToMyEntityDto2Mapper adds 1 to number of the source.
+    }
+
     [Fact]
     public void Should_Use_Destination_Object_Constructor_If_Available()
     {