更新一对一关系实体框架核心时出错

Question

When I update entity Framework row entry which has one to one relationship to another table. I get this error on _context.SaveChanges(); . I have a class called NewsletterComponents with one-to-one relation with NewsletterNewPlants . Not sure why the row fails to update throwing duplicate errors. Should I delete it first then reinsert it?

Error Message

SqlException: Cannot insert duplicate key row in object 'dbo.NewsletterNewPlants' with unique index 'IX_NewsletterNewPlants_NewPlantComponentId'. The duplicate key value is (169).

OnPostUPdate Method

public IActionResult OnPostUpdateComponent(NewsletterComponents component, int? newsId, int? shortArticleId)
        {
            var dbComponent = _context.NewsletterComponents.Find(component.NewsletterComponentId);
            if (dbComponent == null)
            {
                return RedirectToPage("./Index");
            }
            dbComponent.NewsletterNewPlants = component.newsletterNewPlants;
            dbComponent.NewsletterComponentSubline = component.NewsletterComponentSubline;
            dbComponent.NewsletterComponentHeadline = component.NewsletterComponentHeadline;
            _context.Update(dbComponent);
            _context.SaveChanges();

            return RedirectToPage(new { id = dbComponent.NewsletterComponentId});
        }

Parent NewsletterComponents Model

public partial class NewsletterComponents
    {
        public int NewsletterComponentId { get; set; }
        public string ApplicationId { get; set; }
        public string NewsletterComponentHeadline { get; set; }
        public string NewsletterComponentSubline { get; set; }
        public virtual NewsletterNewPlants NewsletterNewPlants { get; set; }


    }

Child NewsletterNewPlants Model

public class NewsletterNewPlants
    {
        [Key]
        public int Id { get; set; }

        [ForeignKey("NewsletterComponents")]
        public int NewPlantComponentId { get; set; }
        public int? NewPlant1 { get; set; }
        public string NewPlant1SubHeadline { get; set; }
        public int? NewPlant2 { get; set; }
        public string NewPlant2SubHeadline { get; set; }
        public int? NewPlant3 { get; set; }
        public string NewPlant3SubHeadline { get; set; }
        public string NewPlantMonth { get; set; }

        public virtual NewsletterComponents NewsletterComponents { get; set; }

    }

Answer 1

I was getting only NewsletterComponents I modified the code to get a reference of newsletterNewPlants also.

I changed the following line

var dbComponent = _context.NewsletterComponents.Find(component.NewsletterComponentId);

to

var dbComponent = _context.NewsletterComponents.Include(t => t.NewsletterNewPlants).FirstOrDefault(t => t.NewsletterComponentId == component.NewsletterComponentId);