Value transformers in global, profiles, type maps, and members

src/AutoMapper/Configuration/IProfileConfiguration.cs

@@ -44,5 +44,6 @@ public interface IProfileConfiguration
         INamingConvention DestinationMemberNamingConvention { get; }
         IEnumerable<ITypeMapConfiguration> TypeMapConfigs { get; }
         IEnumerable<ITypeMapConfiguration> OpenTypeMapConfigs { get; }
+        IEnumerable<ValueTransformerConfiguration> ValueTransformers { get; }
     }
 }

src/AutoMapper/Configuration/MappingExpression.cs

@@ -134,6 +134,7 @@ public class MappingExpression<TSource, TDestination> : IMappingExpression<TSour
         private readonly List<IPropertyMapConfiguration> _memberConfigurations = new List<IPropertyMapConfiguration>();
         private readonly List<SourceMappingExpression> _sourceMemberConfigurations = new List<SourceMappingExpression>();
         private readonly List<CtorParamConfigurationExpression<TSource>> _ctorParamConfigurations = new List<CtorParamConfigurationExpression<TSource>>();
+        private readonly List<ValueTransformerConfiguration> _valueTransformers = new List<ValueTransformerConfiguration>();
         private MappingExpression<TDestination, TSource> _reverseMap;
         private Action<IMemberConfigurationExpression<TSource, TDestination, object>> _allMemberOptions;
         private Func<MemberInfo, bool> _memberFilter;
@@ -156,6 +157,7 @@ public MappingExpression(MemberList memberList, Type sourceType, Type destinatio
         public Type DestinationType => Types.DestinationType;
         public bool IsOpenGeneric { get; }
         public ITypeMapConfiguration ReverseTypeMap => _reverseMap;
+        public IList<ValueTransformerConfiguration> ValueTransformers => _valueTransformers;
         protected List<Action<TypeMap>> TypeMapActions { get; } = new List<Action<TypeMap>>();
 
         public IMappingExpression<TSource, TDestination> PreserveReferences()
@@ -529,6 +531,15 @@ private void CheckIsDerived(Type derivedType, Type baseType)
 
             return this;
         }
+
+        public IMappingExpression<TSource, TDestination> AddTransform<TValue>(Expression<Func<TValue, TValue>> transformer)
+        {
+            var config = new ValueTransformerConfiguration(typeof(TValue), transformer);
+
+            _valueTransformers.Add(config);
+
+            return this;
+        }
 
         private IPropertyMapConfiguration GetDestinationMemberConfiguration(MemberInfo destinationMember) =>
             _memberConfigurations.FirstOrDefault(m => m.DestinationMember == destinationMember);
@@ -573,6 +584,10 @@ public void Configure(TypeMap typeMap)
             {
                 paramConfig.Configure(typeMap);
             }
+            foreach (var valueTransformer in _valueTransformers)
+            {
+                typeMap.AddValueTransformation(valueTransformer);
+            }
 
             if (_reverseMap != null)
             {

src/AutoMapper/Configuration/MemberConfigurationExpression.cs

@@ -233,6 +233,16 @@ public void PreCondition(Func<TSource, ResolutionContext, bool> condition)
             });
         }
 
+        public void AddTransform<TValue>(Expression<Func<TValue, TValue>> transformer)
+        {
+            PropertyMapActions.Add(pm =>
+            {
+                var config = new ValueTransformerConfiguration(typeof(TValue), transformer);
+
+                pm.AddValueTransformation(config);
+            });
+        }
+
         public void ExplicitExpansion()
         {
             PropertyMapActions.Add(pm => pm.ExplicitExpansion = true);

src/AutoMapper/Execution/TypeMapPlanBuilder.cs

@@ -5,7 +5,7 @@ namespace AutoMapper.Execution
     using System.Linq;
     using System.Linq.Expressions;
     using System.Reflection;
-    using AutoMapper.Configuration;
+    using Configuration;
     using static System.Linq.Expressions.Expression;
     using static Internal.ExpressionFactory;
     using static ExpressionBuilder;
@@ -468,7 +468,7 @@ private Expression BuildValueResolverFunc(PropertyMap propertyMap, Expression de
                 var returnType = destinationNullable && destinationPropertyType.GetTypeOfNullable() ==
                                  nullCheckedExpression.Type
                     ? destinationPropertyType
-                    : nullCheckedExpression.Type;
+                    : nullCheckedExpression.Type;
                 valueResolverFunc =
                     TryCatch(
                         ToType(nullCheckedExpression, returnType),
@@ -522,6 +522,12 @@ private Expression BuildValueResolverFunc(PropertyMap propertyMap, Expression de
                     );
             }
 
+            valueResolverFunc = propertyMap.ValueTransformers
+                .Concat(_typeMap.ValueTransformers)
+                .Concat(_typeMap.Profile.ValueTransformers)
+                .Where(vt => vt.IsMatch(propertyMap))
+                .Aggregate(valueResolverFunc, (current, vtConfig) => ToType(ReplaceParameters(vtConfig.TransformerExpression, ToType(current, vtConfig.ValueType)), propertyMap.DestinationPropertyType));
+
             return valueResolverFunc;
         }
 

src/AutoMapper/IMappingExpression.cs

@@ -1,4 +1,5 @@
 using System;
+using System.Collections.Generic;
 using System.Linq.Expressions;
 
 namespace AutoMapper
@@ -181,6 +182,9 @@ IMappingExpression BeforeMap<TMappingAction>()
         /// <returns>Itself</returns>
         IMappingExpression AfterMap<TMappingAction>()
             where TMappingAction : IMappingAction<object, object>;
+
+        IList<ValueTransformerConfiguration> ValueTransformers { get; }
+
     }
 
     /// <summary>
@@ -439,5 +443,15 @@ public interface IMappingExpression<TSource, TDestination>
         /// </summary>
         /// <returns>Itself</returns>
         IMappingExpression<TSource, TDestination> DisableCtorValidation();
+
+        IList<ValueTransformerConfiguration> ValueTransformers { get; }
+
+        /// <summary>
+        /// Apply a transformation function after any resolved destination member value with the given type
+        /// </summary>
+        /// <typeparam name="TValue">Value type to match and transform</typeparam>
+        /// <param name="transformer">Transformation expression</param>
+        /// <returns>Itself</returns>
+        IMappingExpression<TSource, TDestination> AddTransform<TValue>(Expression<Func<TValue, TValue>> transformer);
     }
 }

src/AutoMapper/IMemberConfigurationExpression.cs

@@ -10,7 +10,7 @@ namespace AutoMapper
     /// <typeparam name="TSource">Source type for this member</typeparam>
     /// <typeparam name="TMember">Type for this member</typeparam>
     /// <typeparam name="TDestination">Destination type for this map</typeparam>
-    public interface IMemberConfigurationExpression<TSource, out TDestination, TMember>
+    public interface IMemberConfigurationExpression<TSource, TDestination, TMember>
     {
         /// <summary>
         /// Do not precompute the execution plan for this member, just map it at runtime.
@@ -199,6 +199,13 @@ void ResolveUsing<TValueResolver>()
         /// The destination member being configured.
         /// </summary>
         MemberInfo DestinationMember { get; }
+
+        /// <summary>
+        /// Apply a transformation function after any resolved destination member value with the given type
+        /// </summary>
+        /// <typeparam name="TValue">Value type to match and transform</typeparam>
+        /// <param name="transformer">Transformation expression</param>
+        void AddTransform<TValue>(Expression<Func<TValue, TValue>> transformer);
     }
 
     /// <summary>

src/AutoMapper/IProfileExpression.cs

@@ -1,4 +1,6 @@
 using System;
+using System.Collections.Generic;
+using System.Linq.Expressions;
 using System.Reflection;
 using AutoMapper.Configuration.Conventions;
 using AutoMapper.Mappers;
@@ -152,5 +154,10 @@ public interface IProfileExpression
         /// </summary>
         /// <param name="type">Static type that contains extension methods</param>
         void IncludeSourceExtensionMethods(Type type);
+
+        /// <summary>
+        /// Value transformers. Modify the list directly or use <see cref="ValueTransformerConfigurationExtensions.Add{TValue}"/>
+        /// </summary>
+        IList<ValueTransformerConfiguration> ValueTransformers { get; }
     }
 }

src/AutoMapper/Profile.cs

@@ -1,6 +1,7 @@
 using System;
 using System.Collections.Generic;
 using System.Linq;
+using System.Linq.Expressions;
 using System.Reflection;
 using System.Runtime.CompilerServices;
 using AutoMapper.Configuration;
@@ -25,8 +26,8 @@ public abstract class Profile : IProfileExpression, IProfileConfiguration
         private readonly List<ITypeMapConfiguration> _openTypeMapConfigs = new List<ITypeMapConfiguration>();
         private readonly List<MethodInfo> _sourceExtensionMethods = new List<MethodInfo>();
         private readonly IList<ConditionalObjectMapper> _typeConfigurations = new List<ConditionalObjectMapper>();
-
         private readonly List<ITypeMapConfiguration> _typeMapConfigs = new List<ITypeMapConfiguration>();
+        private readonly List<ValueTransformerConfiguration> _valueTransformerConfigs = new List<ValueTransformerConfiguration>();
 
         protected Profile(string profileName)
             : this() => ProfileName = profileName;
@@ -63,6 +64,7 @@ protected Profile(string profileName, Action<IProfileExpression> configurationAc
         IEnumerable<IConditionalObjectMapper> IProfileConfiguration.TypeConfigurations => _typeConfigurations;
         IEnumerable<ITypeMapConfiguration> IProfileConfiguration.TypeMapConfigs => _typeMapConfigs;
         IEnumerable<ITypeMapConfiguration> IProfileConfiguration.OpenTypeMapConfigs => _openTypeMapConfigs;
+        IEnumerable<ValueTransformerConfiguration> IProfileConfiguration.ValueTransformers => _valueTransformerConfigs;
 
         public virtual string ProfileName { get; }
 
@@ -75,6 +77,7 @@ protected Profile(string profileName, Action<IProfileExpression> configurationAc
         public INamingConvention SourceMemberNamingConvention { get; set; }
         public INamingConvention DestinationMemberNamingConvention { get; set; }
 
+        public IList<ValueTransformerConfiguration> ValueTransformers => _valueTransformerConfigs;
 
         public void DisableConstructorMapping()
         {
@@ -182,6 +185,10 @@ public void IncludeSourceExtensionMethods(Type type)
                             m.GetParameters().Length == 1));
         }
 
+        public void ApplyTransform<TValue>(Expression<Func<TValue, TValue>> transformer)
+        {
+        }
+
         private IMappingExpression<TSource, TDestination> CreateMappingExpression<TSource, TDestination>(
             MemberList memberList)
         {

src/AutoMapper/ProfileMap.cs

@@ -47,6 +47,7 @@ public ProfileMap(IProfileConfiguration profile, IConfiguration configuration)
                     : Enumerable.Empty<IConditionalObjectMapper>())
                 .ToArray();
 
+            ValueTransformers = profile.ValueTransformers.Concat(configuration?.ValueTransformers ?? Enumerable.Empty<ValueTransformerConfiguration>()).ToArray();
 
             MemberConfigurations = profile.MemberConfigurations.ToArray();
 
@@ -95,6 +96,7 @@ public ProfileMap(IProfileConfiguration profile, IConfiguration configuration)
         public IEnumerable<IConditionalObjectMapper> TypeConfigurations { get; }
         public IEnumerable<string> Prefixes { get; }
         public IEnumerable<string> Postfixes { get; }
+        public IEnumerable<ValueTransformerConfiguration> ValueTransformers { get; }
 
         public TypeDetails CreateTypeDetails(Type type) => _typeDetails.GetOrAdd(type);
 

src/AutoMapper/PropertyMap.cs

@@ -17,6 +17,7 @@ namespace AutoMapper
     public class PropertyMap
     {
         private readonly List<MemberInfo> _memberChain = new List<MemberInfo>();
+        private readonly List<ValueTransformerConfiguration> _valueTransformerConfigs = new List<ValueTransformerConfiguration>();
 
         public PropertyMap(PathMap pathMap)
         {
@@ -68,6 +69,7 @@ public PropertyMap(PropertyMap inheritedMappedProperty, TypeMap typeMap)
         public bool ExplicitExpansion { get; set; }
         public object NullSubstitute { get; set; }
         public ValueResolverConfiguration ValueResolverConfig { get; set; }
+        public IEnumerable<ValueTransformerConfiguration> ValueTransformers => _valueTransformerConfigs;
 
         public MemberInfo SourceMember
         {
@@ -142,6 +144,11 @@ public void MapFrom(LambdaExpression sourceMember)
             Ignored = false;
         }
 
+        public void AddValueTransformation(ValueTransformerConfiguration valueTransformerConfiguration)
+        {
+            _valueTransformerConfigs.Add(valueTransformerConfiguration);
+        }
+
         private class MemberFinderVisitor : ExpressionVisitor
         {
             public MemberExpression Member { get; private set; }

src/AutoMapper/TypeMap.cs

@@ -29,6 +29,7 @@ public class TypeMap
         private PropertyMap[] _orderedPropertyMaps;
         private bool _sealed;
         private readonly IList<TypeMap> _inheritedTypeMaps = new List<TypeMap>();
+        private readonly List<ValueTransformerConfiguration> _valueTransformerConfigs = new List<ValueTransformerConfiguration>();
 
         public TypeMap(TypeDetails sourceType, TypeDetails destinationType, MemberList memberList, ProfileMap profile)
         {
@@ -79,7 +80,8 @@ public PathMap FindOrCreatePathMapFor(LambdaExpression destinationExpression, Me
         public IEnumerable<TypePair> IncludedBaseTypes => _includedBaseTypes;
 
         public IEnumerable<LambdaExpression> BeforeMapActions => _beforeMapActions;
-        public IEnumerable<LambdaExpression> AfterMapActions => _afterMapActions; 
+        public IEnumerable<LambdaExpression> AfterMapActions => _afterMapActions;
+        public IEnumerable<ValueTransformerConfiguration> ValueTransformers => _valueTransformerConfigs;
 
         public bool PreserveReferences { get; set; }
         public LambdaExpression Condition { get; set; }
@@ -259,6 +261,11 @@ public void AddAfterMapAction(LambdaExpression afterMap)
             }
         }
 
+        public void AddValueTransformation(ValueTransformerConfiguration valueTransformerConfiguration)
+        {
+            _valueTransformerConfigs.Add(valueTransformerConfiguration);
+        }
+
         public void Seal(IConfigurationProvider configurationProvider, Stack<TypeMap> typeMapsPath = null)
         {
             if(_sealed)

src/AutoMapper/ValueTransformerConfiguration.cs

@@ -0,0 +1,40 @@
+using System;
+using System.Collections.Generic;
+using System.Linq.Expressions;
+
+namespace AutoMapper
+{
+    public class ValueTransformerConfiguration
+    {
+        public ValueTransformerConfiguration(Type valueType, LambdaExpression transformerExpression)
+        {
+            ValueType = valueType;
+            TransformerExpression = transformerExpression;
+        }
+
+        public Type ValueType { get; }
+        public LambdaExpression TransformerExpression { get; }
+
+        public bool IsMatch(PropertyMap propertyMap)
+        {
+            return ValueType.IsAssignableFrom(propertyMap.DestinationPropertyType);
+        }
+    }
+
+    public static class ValueTransformerConfigurationExtensions
+    {
+        /// <summary>
+        /// Apply a transformation function after any resolved destination member value with the given type
+        /// </summary>
+        /// <typeparam name="TValue">Value type to match and transform</typeparam>
+        /// <param name="valueTransformers">Value transformer list</param>
+        /// <param name="transformer">Transformation expression</param>
+        public static void Add<TValue>(this IList<ValueTransformerConfiguration> valueTransformers,
+            Expression<Func<TValue, TValue>> transformer)
+        {
+            var config = new ValueTransformerConfiguration(typeof(TValue), transformer);
+
+            valueTransformers.Add(config);
+        }
+    }
+}

src/UnitTests/Bug/MultiThreadingIssues.cs

@@ -75,7 +75,7 @@ static void doMapping()
         {
             var source = createSource();
 
-            Console.WriteLine(@"Mapping {0} on thread {1}", source.GetType(), Thread.CurrentThread.ManagedThreadId);
+            Debug.WriteLine(@"Mapping {0} on thread {1}", source.GetType(), Thread.CurrentThread.ManagedThreadId);
 
             var config = new MapperConfiguration(cfg => cfg.CreateMap(source.GetType(), typeof(DestType)));
 

src/UnitTests/ConfigurationRules.cs

@@ -1,5 +1,4 @@
-using System;
-using Xunit;
+using Xunit;
 
 namespace AutoMapper.UnitTests
 {
@@ -59,15 +58,6 @@ public void Should_throw_for_multiple_create_map_calls_in_different_profiles()
             });
 
             typeof(DuplicateTypeMapConfigurationException).ShouldBeThrownBy(() => config.AssertConfigurationIsValid());
-
-            try
-            {
-                config.AssertConfigurationIsValid();
-            }
-            catch (DuplicateTypeMapConfigurationException e)
-            {
-                Console.WriteLine(e.ToString());
-            }
         }
 
         [Fact]