Curd opration in mvc

Question

User616860969 posted

Attaching an entity of type 'EntityModel.Models.User' failed because another entity of the same type already has the same primary key value. This can happen when using the 'Attach' method or setting the state of an entity to 'Unchanged' or 'Modified' if any entities in the graph have conflicting key values. This may be because some entities are new and have not yet received database-generated key values. In this case use the 'Add' method or the 'Added' entity state to track the graph and then set the state of non-new entities to 'Unchanged' or 'Modified' as appropriate.

my code:

public abstract class RepositoryBase<T> : IRepository<T> where T : class

{

        #region Properties

        private AADbContext dataContext;

        private readonly IDbSet<T> dbSet;

 

        protected IdbAA dbAA

        {

            get; private set;

        }

        protected AADbContext DbContext

        {

            get { return dataContext ?? (dataContext = dbAA.Init()); }

        }

        #endregion

 protected RepositoryBase(IdbAA dbAA)

        {

            dbAA = dbAA;

            dbSet = DbContext.Set<T>();

        }

#region IRepository Members

      public void Update(T entity, T NewEntity)

        {

            this.dbSet.Attach(entity);

            dataContext.Entry(entity).CurrentValues.SetValues(NewEntity);

            dataContext.Entry(entity).State = EntityState.Modified;

            dataContext.SaveChanges();

        }

 

        public virtual void Delete(T entity)

        { 

           this.dbSet.Remove(entity);

            dataContext.SaveChanges();

}

#endregion

}

Answer 1

User1400794712 posted

Hi sanjaykumar pushadapu,

As we can see in the code, you are trying to attach the entity before updating. It will set the entity's state to unchanged. It will conflict with updating. Please remove this code form the update method.

public void Update(T NewEntity)
{
    if (ModelState.IsValid)
    {
        dataContext.Entry(NewEntity).State = EntityState.Modified;
        dataContext.SaveChanges();
    }
}

For more details, please refer to this article.

Best Regards,
Daisy