自定义 EF Core 保存方法中的 InvalidOperationException

Question

I am writing a custom save generic method for our framework in EF Core. The idea is to have a method that can make partial updates.

The code is like this:

public IEnumerable<T> UpdateEntitiesByProperties(IEnumerable<UpdateByPropertiesData<T>> entitiesAndProperties)
{
   List<T> entities = new List<T>();

   foreach (var entityAndProperties in entitiesAndProperties)
   {
        T contextEntity = this.context.Find<T>(entityAndProperties.Entity.Id);
        EntityEntry<T> changeTrackerEntityEntry = this.context.Entry(contextEntity);

        changeTrackerEntityEntry.CurrentValues.SetValues(entityAndProperties.Entity);

        foreach (var property in changeTrackerEntityEntry.Properties.Where(p => !p.Metadata.IsConcurrencyToken))
        {
            property.IsModified = entityAndProperties.UpdatedProperties.Contains(property.Metadata.Name);
        }

     entities.Add(contextEntity);
   }

   return entities;
}

If I change the code to this, it works correctly:

public IEnumerable<T> UpdateEntitiesByProperties(IEnumerable<UpdateByPropertiesData<T>> entitiesAndProperties)
{
   List<T> entities = new List<T>();

   foreach (var entityAndProperties in entitiesAndProperties)
   {
        T contextEntity = this.context.Find<T>(entityAndProperties.Entity.Id);
        EntityEntry<T> changeTrackerEntityEntry = this.context.Entry(contextEntity);

        changeTrackerEntityEntry.CurrentValues.SetValues(entityAndProperties.Entity);

        foreach (var property in changeTrackerEntityEntry.Properties.Where(p => !p.Metadata.IsConcurrencyToken))
        {
            if(entityAndProperties.UpdatedProperties.Contains(property.Metadata.Name)
            {
                property.CurrentValue = typeof(T).GetTypeInfo().GetDeclaredProperty(property.Metadata.Name).GetValue(entityAndProperties.Entity);  
            }
        }

     entities.Add(contextEntity);
   }

   return entities;
}

The method is working with simple entities but throws an InvalidOperationException when the entity in entitiesAndProperties does not contain a required field.

The exception text is:

The property 'Name' on entity type 'User' is marked as null, but this cannot be saved because the property is marked as required.

It should not be a problem, because the entity already exists in database with the required field value, contextEntity reflects that, but seems the CurrentValues.SetValues overrides this.

Answer 1

Although I agree with @Gert Arnold comment that you should probably avoid CurrentValues.SetValues in such scenario, the code looks to me pretty legal, so I'm considering this to be a current EF Core implementation bug.

It's the only case AFAIK which doesn't change the CurrentValue of the property in the target object, but marks it somewhere internally as invalid. Normally setting IsModified = false or CurrentValue = OriginalValue restores the property value, but not in this case (because the value is the same), which is ok, but the problem is that it also doesn't remove the "invalid mark", which I think is the bug.

I would suggest using your current workaround and posting the issue to their issue tracker.