Question

In our database we have a user. A user can have certain metadata (Like their location, age, etc) associated with them. In addition to that they have a profile image.
A user can edit any of these things at any time.

The problem we run into is that when a user goes to edit their information, but they don’t choose an image — the previous image gets erased (Null).

I figure that when we go to save the modified user, we should be able to say if(user.profileImage == null) don't save it

I figure that would come into play in our user repository which uses the following code:

public void SaveUser(Domain.Entities.User user)
        {
            if (user.UserId == 0)
            {
                context.Users.Add(user);
            }
            else
            {
                context.Entry(user).State = EntityState.Modified;
                //The logic would be here
            }
            context.SaveChanges();
        }

However I seems that no matter what we try it doesn’t work.

So my question is: Is there a way to check changes to individual fields instead of the entire EntityState?

Answer 1

I ended up storing image data in the Session and then if the image upload was null I simply inserted the session attribute into my image, effectively keeping the old image if left empty.

Session["image"] = productService.GetProduct(id).Image;

Then in the post I said…

if (image != null)
                {
                    product.ImageType = image.ContentType;
                    product.Image = new byte[image.ContentLength];
                    image.InputStream.Read(product.Image, 0, image.ContentLength);
                }
                else
                {
                    product.Image = (byte[])Session["image"];
                }