Resolved #599: Introduce IMapTo and IMapFrom interfaces to allow object map itself

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

@@ -1,5 +1,5 @@
-using System;
 using Microsoft.Extensions.DependencyInjection;
+using System;
 using Volo.Abp.DependencyInjection;
 
 namespace Volo.Abp.ObjectMapping
@@ -22,7 +22,6 @@ namespace Volo.Abp.ObjectMapping
                 return default;
             }
 
-            //Check if a specific mapper is registered
             using (var scope = _serviceProvider.CreateScope())
             {
                 var specificMapper = scope.ServiceProvider.GetService<IObjectMapper<TSource, TDestination>>();
@@ -32,6 +31,26 @@ namespace Volo.Abp.ObjectMapping
                 }
             }
 
+            if (source is IMapTo<TDestination> mapperSource)
+            {
+                return mapperSource.MapTo();
+            }
+
+            if (typeof(IMapFrom<TSource>).IsAssignableFrom(typeof(TDestination)))
+            {
+                try
+                {
+                    //TODO: Check if TDestination has a proper constructor which takes TSource
+                    //TODO: Check if TDestination has an empty constructor (in this case, use MapFrom)
+
+                    return (TDestination) Activator.CreateInstance(typeof(TDestination), source);
+                }
+                catch
+                {
+                    //TODO: Remove catch when TODOs are implemented above
+                }
+            }
+
             return AutoMap<TSource, TDestination>(source);
         }
 
@@ -42,7 +61,6 @@ namespace Volo.Abp.ObjectMapping
                 return default;
             }
 
-            //Check if a specific mapper is registered
             using (var scope = _serviceProvider.CreateScope())
             {
                 var specificMapper = scope.ServiceProvider.GetService<IObjectMapper<TSource, TDestination>>();
@@ -52,6 +70,18 @@ namespace Volo.Abp.ObjectMapping
                 }
             }
 
+            if (source is IMapTo<TDestination> mapperSource)
+            {
+                mapperSource.MapTo(destination);
+                return destination;
+            }
+
+            if (destination is IMapFrom<TSource> mapperDestination)
+            {
+                mapperDestination.MapFrom(source);
+                return destination;
+            }
+
             return AutoMap(source, destination);
         }
 

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

@@ -0,0 +1,7 @@
+namespace Volo.Abp.ObjectMapping
+{
+    public interface IMapFrom<in TSource>
+    {
+        void MapFrom(TSource source);
+    }
+}

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

@@ -0,0 +1,9 @@
+namespace Volo.Abp.ObjectMapping
+{
+    public interface IMapTo<TDestination>
+    {
+        TDestination MapTo();
+
+        void MapTo(TDestination destination);
+    }
+}

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

@@ -1,3 +1,4 @@
+using System;
 using Microsoft.Extensions.DependencyInjection;
 using Shouldly;
 using Volo.Abp.AutoMapper.SampleClasses;
@@ -21,5 +22,43 @@ namespace Volo.Abp.AutoMapper
             var dto = _objectMapper.Map<MyEntity, MyEntityDto2>(new MyEntity { Number = 42 });
             dto.Number.ShouldBe(43); //MyEntityToMyEntityDto2Mapper adds 1 to number of the source.
         }
+
+        [Fact]
+        public void Should_Use_Destination_Object_Constructor_If_Available()
+        {
+            var id = Guid.NewGuid();
+            var dto = _objectMapper.Map<MyEntity, MyEntityDtoWithMappingMethods>(new MyEntity { Number = 42, Id = id});
+            dto.Key.ShouldBe(id);
+            dto.No.ShouldBe(42);
+        }
+
+        [Fact]
+        public void Should_Use_Destination_Object_MapFrom_Method_If_Available()
+        {
+            var id = Guid.NewGuid();
+            var dto = new MyEntityDtoWithMappingMethods();
+            _objectMapper.Map(new MyEntity { Number = 42, Id = id }, dto);
+            dto.Key.ShouldBe(id);
+            dto.No.ShouldBe(42);
+        }
+
+        [Fact]
+        public void Should_Use_Source_Object_Method_If_Available_To_Create_New_Object()
+        {
+            var id = Guid.NewGuid();
+            var entity = _objectMapper.Map<MyEntityDtoWithMappingMethods, MyEntity>(new MyEntityDtoWithMappingMethods{Key = id, No = 42});
+            entity.Id.ShouldBe(id);
+            entity.Number.ShouldBe(42);
+        }
+
+        [Fact]
+        public void Should_Use_Source_Object_Method_If_Available_To_Map_Existing_Object()
+        {
+            var id = Guid.NewGuid();
+            var entity = new MyEntity();
+            _objectMapper.Map(new MyEntityDtoWithMappingMethods { Key = id, No = 42 }, entity);
+            entity.Id.ShouldBe(id);
+            entity.Number.ShouldBe(42);
+        }
     }
 }

framework/test/Volo.Abp.AutoMapper.Tests/Volo/Abp/AutoMapper/SampleClasses/MyEntityDtoWithMappingMethods.cs

@@ -0,0 +1,44 @@
+using System;
+using Volo.Abp.ObjectMapping;
+
+namespace Volo.Abp.AutoMapper.SampleClasses
+{
+    //TODO: Move tests to Volo.Abp.ObjectMapping test project
+    public class MyEntityDtoWithMappingMethods : IMapFrom<MyEntity>, IMapTo<MyEntity>
+    {
+        public Guid Key { get; set; }
+
+        public int No { get; set; }
+
+        public MyEntityDtoWithMappingMethods()
+        {
+            
+        }
+
+        public MyEntityDtoWithMappingMethods(MyEntity entity)
+        {
+            MapFrom(entity);
+        }
+
+        public void MapFrom(MyEntity source)
+        {
+            Key = source.Id;
+            No = source.Number;
+        }
+
+        MyEntity IMapTo<MyEntity>.MapTo()
+        {
+            return new MyEntity
+            {
+                Id = Key,
+                Number = No
+            };
+        }
+
+        void IMapTo<MyEntity>.MapTo(MyEntity destination)
+        {
+            destination.Id = Key;
+            destination.Number = No;
+        }
+    }
+}