`MapExtraPropertiesTo` should ignored if `ExtraProperties` is `null`.

framework/src/Volo.Abp.AutoMapper/AutoMapper/AbpAutoMapperExtensibleDtoExtensions.cs

@@ -1,4 +1,5 @@
 using System.Collections.Generic;
+using Volo.Abp;
 using Volo.Abp.AutoMapper;
 using Volo.Abp.Data;
 using Volo.Abp.ObjectExtending;
@@ -25,6 +26,11 @@ public static class AbpAutoMapperExtensibleDtoExtensions
                             ? new Dictionary<string, object>()
                             : new Dictionary<string, object>(extraProps);
 
+                        if (source.ExtraProperties == null || destination.ExtraProperties == null)
+                        {
+                            return result;
+                        }
+
                         ExtensibleObjectMapper
                             .MapExtraPropertiesTo<TSource, TDestination>(
                                 source.ExtraProperties,

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

@@ -1,5 +1,7 @@
-using Microsoft.Extensions.DependencyInjection;
+using System.Collections.Generic;
+using Microsoft.Extensions.DependencyInjection;
 using Shouldly;
+using Volo.Abp;
 using Volo.Abp.AutoMapper;
 using Volo.Abp.Data;
 using Volo.Abp.ObjectExtending.TestObjects;
@@ -64,4 +66,19 @@ public class AbpAutoMapperExtensibleDtoExtensions_Tests : AbpIntegratedTest<Auto
         personDto.HasProperty("IsActive").ShouldBe(false);
         personDto.IsActive.ShouldBe(true);
     }
+
+    [Fact]
+    public void MapExtraPropertiesTo_Should_Ignored_If_ExtraProperties_Is_Null()
+    {
+        var person = new ExtensibleTestPerson();
+        person.SetExtraPropertiesAsNull();
+
+        var personDto = new ExtensibleTestPersonDto();
+        personDto.SetExtraPropertiesAsNull();
+
+        Should.NotThrow(() => _objectMapper.Map(person, personDto));
+
+        person.ExtraProperties.ShouldBe(null);
+        personDto.ExtraProperties.ShouldBe(null);
+    }
 }

framework/test/Volo.Abp.ObjectExtending.Tests/Volo/Abp/ObjectExtending/TestObjects/ExtensibleTestPerson.cs

@@ -12,6 +12,11 @@ public class ExtensibleTestPerson : ExtensibleObject
     {
 
     }
+
+    public void SetExtraPropertiesAsNull()
+    {
+        ExtraProperties = null;
+    }
 }
 
 public enum ExtensibleTestEnumProperty

framework/test/Volo.Abp.ObjectExtending.Tests/Volo/Abp/ObjectExtending/TestObjects/ExtensibleTestPersonDto.cs

@@ -2,5 +2,8 @@
 
 public class ExtensibleTestPersonDto : ExtensibleObject
 {
-
+    public void SetExtraPropertiesAsNull()
+    {
+        ExtraProperties = null;
+    }
 }