添加时EfCore包含相关对象

Question

I want to do this, but entry.Entity.User is NULL.

var entry = this.myContext.Verifications.Add(new DbVerification()
        {
            UserId = model.UserId,
            Created = DateTimeOffset.UtcNow,
            Method = model.VerificationType
        });
entry.Entity.User.FirstName = "peanut";

I can explicitly load the user with

this.myContext.Users.First(x => x.Id == model.UserId)

but can i Include the entry.Entity.User object somehow without doing this ?

Just like I can do this

this.myContext.Verifications.Include(x => x.User).Where(doesntmatter);

to include the user object in the entity, is there anyway to include it in a similiar way using context.Verifications.Add as shown above.

Answer 1

One thing you could do is use Explicit Loading :

var entry = this.myContext.Verifications.Add(new DbVerification()
        {
            UserId = model.UserId,
            Created = DateTimeOffset.UtcNow,
            Method = model.VerificationType
        });
context.Entry(entry.Entity).Reference(p => p.User).Load();// Add this line
entry.Entity.User.FirstName = "peanut";

But at the end if you don't have the user entity instance in memory you're going to need to do a round trip to fetch the user and make the change, so there is not much difference compared with this:

var entry = this.myContext.Verifications.Add(new DbVerification()
            {
                UserId = model.UserId,
                Created = DateTimeOffset.UtcNow,
                Method = model.VerificationType
            });
var user=this.myContext.Users.First(x => x.Id == model.UserId);
user.FirstName = "peanut";
myContext.SaveChanges();