Merge pull request #2162 from AutoMapper/ForPathIgnore

Allow ignores on reverse map paths

Author: jbogard

src/AutoMapper/Configuration/PathConfigurationExpression.cs

@@ -28,6 +28,11 @@ public void MapFrom<TSourceMember>(Expression<Func<TSource, TSourceMember>> sour
             MapFromUntyped(sourceExpression);
         }
 
+        public void Ignore()
+        {
+            PathMapActions.Add(pm => pm.Ignored = true);
+        }
+
         public void MapFromUntyped(LambdaExpression sourceExpression)
         {
             _sourceExpression = sourceExpression;
@@ -39,14 +44,6 @@ public void MapFromUntyped(LambdaExpression sourceExpression)
 
         public void Configure(TypeMap typeMap)
         {
-            //var destMember = DestinationMember;
-
-            //if(destMember.DeclaringType.IsGenericType())
-            //{
-            //    var destTypeInfo = typeMap.Profile.CreateTypeDetails(destMember.DeclaringType);
-            //    destMember = destTypeInfo.PublicReadAccessors.Single(m => m.Name == destMember.Name);
-            //}
-
             var pathMap = typeMap.FindOrCreatePathMapFor(_destinationExpression, MemberPath, typeMap);
 
             Apply(pathMap);

src/AutoMapper/Execution/TypeMapPlanBuilder.cs

@@ -188,20 +188,16 @@ private Expression CreateDestinationFunc(out bool constructorMapping)
         private Expression CreateAssignmentFunc(Expression destinationFunc, bool constructorMapping)
         {
             var actions = new List<Expression>();
-            foreach(var propertyMap in _typeMap.GetPropertyMaps())
+            foreach(var propertyMap in _typeMap.GetPropertyMaps().Where(pm => pm.CanResolveValue()))
             {
-                if(!propertyMap.CanResolveValue())
-                {
-                    continue;
-                }
                 var property = TryPropertyMap(propertyMap);
                 if(constructorMapping && _typeMap.ConstructorParameterMatches(propertyMap.DestinationProperty.Name))
                 {
                     property = IfThen(NotEqual(_initialDestination, Constant(null)), property);
                 }
                 actions.Add(property);
             }
-            foreach(var pathMap in _typeMap.PathMaps)
+            foreach(var pathMap in _typeMap.PathMaps.Where(pm => !pm.Ignored))
             {
                 actions.Add(HandlePath(pathMap));
             }

src/AutoMapper/IPathConfigurationExpression.cs

@@ -18,5 +18,10 @@ public interface IPathConfigurationExpression<TSource, out TDestination>
         /// <typeparam name="TSourceMember">Member type of the source member to use</typeparam>
         /// <param name="sourceMember">Expression referencing the source member to map against</param>
         void MapFrom<TSourceMember>(Expression<Func<TSource, TSourceMember>> sourceMember);
+
+        /// <summary>
+        /// Ignore this member for configuration validation and skip during mapping
+        /// </summary>
+        void Ignore();
     }
 }

src/AutoMapper/PathMap.cs

@@ -21,5 +21,6 @@ public PathMap(LambdaExpression destinationExpression, MemberPath memberPath, Ty
         public LambdaExpression SourceExpression { get; set; }
         public MemberPath MemberPath { get; }
         public MemberInfo DestinationMember => MemberPath.Last;
+        public bool Ignored { get; set; }
     }
 }

src/UnitTests/ForPath.cs

@@ -131,6 +131,55 @@ public void Should_unflatten()
         }
     }
 
+    public class ForPathWithIgnoreShouldNotSetValue : AutoMapperSpecBase
+    {
+        public partial class TimesheetModel
+        {
+            public int ID { get; set; }
+            public DateTime? StartDate { get; set; }
+            public int? Contact { get; set; }
+            public ContactModel ContactNavigation { get; set; }
+        }
+
+        public class TimesheetViewModel
+        {
+            public int? Contact { get; set; }
+            public DateTime? StartDate { get; set; }
+        }
+
+        public class ContactModel
+        {
+            public int Id { get; set; }
+        }
+
+        protected override MapperConfiguration Configuration { get; } = new MapperConfiguration(cfg =>
+        {
+            cfg.CreateMap<TimesheetModel, TimesheetViewModel>()
+                .ForMember(d => d.Contact, o => o.MapFrom(s => s.ContactNavigation.Id))
+                .ReverseMap()
+                .ForPath(s => s.ContactNavigation.Id, opt => opt.Ignore());
+        });
+
+        [Fact]
+        public void Should_not_set_value()
+        {
+            var source = new TimesheetModel
+            {
+                Contact = 6,
+                ContactNavigation = new ContactModel
+                {
+                    Id = 5
+                }
+            };
+            var dest = new TimesheetViewModel
+            {
+                Contact = 10
+            };
+            Mapper.Map(dest, source);
+
+            source.ContactNavigation.Id.ShouldEqual(5);
+        }
+    }
 
     public class ForPathWithPrivateSetters : AutoMapperSpecBase
     {