Fix the problem of `ValueObject` return value.

https://github.com/abpframework/abp/pull/12510

framework/src/Volo.Abp.Ddd.Domain/Volo/Abp/Domain/Values/ValueObject.cs

@@ -44,6 +44,6 @@ public abstract class ValueObject
             }
         }
 
-        return !thisValues.MoveNext() && !otherValues.MoveNext();
+        return !thisMoveNext && !otherMoveNext;
     }
 }

framework/test/Volo.Abp.Ddd.Tests/Volo/Abp/Domain/Values/EmailAddress.cs

@@ -0,0 +1,25 @@
+using System.Collections.Generic;
+
+namespace Volo.Abp.Domain.Values;
+
+public class EmailAddress : ValueObject
+{
+    public string Email { get; }
+
+    private EmailAddress()
+    {
+    }
+
+    public EmailAddress(string email)
+    {
+        Email = email;
+    }
+
+    protected override IEnumerable<object> GetAtomicValues()
+    {
+        if (Email != null)
+        {
+            yield return Email;
+        }
+    }
+}

framework/test/Volo.Abp.Ddd.Tests/Volo/Abp/Domain/Values/ValueObject_Tests.cs

@@ -31,5 +31,10 @@ public class ValueObject_Tests
         address2 = new Address(cityId, "Baris Manco", 42, "home");
 
         address1.ValueEquals(address2).ShouldBeFalse();
+
+        var emailAddress1 = new EmailAddress("test@abp.io");
+        var emailAddress2 = new EmailAddress(null);
+
+        emailAddress1.ValueEquals(emailAddress2).ShouldBeFalse();
     }
 }