Updating Nested Objects in Entity Framework

问题

recently I discover that EF doesn't update nested object. For few days I try to figure out how to do this but unfortunately I'm stuck with this problem.

I have Object

public class ProjectEntity : AuditableEntity<int>
{

    public string CustumerCompany { get; set; }
    public string CustomerRepresentative { get; set; }

    public string ProjectTitle { get; set; }
    public string WwsNumber { get; set; }

    [ForeignKey("ParentProjectId")]
    public virtual ProjectEntity ParentProject { get; set; }

    public int? ParentProjectId { get; set; }

    public virtual ICollection<ProjectServicesEntity> Service { get; set; }
}

Then Service object

public class ProjectServicesEntity : AuditableEntity<int>
{
    /// <summary>
    /// Service Number
    /// </summary>
    public int Number { get; set; }
    /// <summary>
    /// Service Name
    /// </summary>
    public string Name { get; set; }

    /// <summary>
    /// Positions
    /// </summary>
    public virtual ICollection<ProjectPositionsEntity> Positions { get; set; }

    [ForeignKey("ProjectId")]
    public virtual ProjectEntity Project { get; set; }

    public int ProjectId { get; set; }
}

and Positions object:

public class ProjectPositionsEntity : AuditableEntity<int>
{
    /// <summary>
    /// Position number
    /// </summary>
    public int Number { get; set; }

    /// <summary>
    /// Position Name
    /// </summary>
    public string Name { get; set; }

    /// <summary>
    /// Organization Unit for position
    /// </summary>
    public virtual ICollection<ProjectsOutsourcedPositionEntity> OrganizationUnit { get; set; }
    /// <summary>
    /// Represents if position is outsourced
    /// </summary>
    public bool OutSource { get; set; }
    /// <summary>
    /// Comments for position
    /// </summary>
    public string Remarks { get; set; }

    [ForeignKey("ServiceId")]
    public virtual ProjectServicesEntity Service { get; set; }

    public int ServiceId { get; set; }

}}

And my update method:

public void Update(T entity)
    {

            DbContext.Entry(entity).State = EntityState.Modified;
            DbContext.SaveChanges();
}

When have page were all data is represented and when I try to edit some data in Service's or in Position's it doesn't update. Anybody had this kind of problem ?

Every example that I saw it was only with nested object that has 1 level deep but as you can see my object has 2 level nest.

回答1:

So I figure out how I can make this work. In specific repository class I made few foreach loops that set EntityState to modified. By our business rules Project required to have Service and Position and OrganizationUnit for Position is optional so I check if it's not null. Here is my solution:

DbContext.Entry(entity).State = EntityState.Modified;
            foreach (var service in entity.Service)
            {
                DbContext.Entry(service).State = EntityState.Modified;
                foreach (var position in service.Positions)
                {
                    DbContext.Entry(position).State = EntityState.Modified;
                    if (position.OrganizationUnit == null) continue;
                    foreach (var organizationUnit in position.OrganizationUnit)
                    {
                        DbContext.Entry(organizationUnit).State = EntityState.Modified;
                    }
                }
            }
            DbContext.SaveChanges();

Now when I want to update my object on any level it will update in my DB.

来源：https://stackoverflow.com/questions/41739901/updating-nested-objects-in-entity-framework

标签

.net

entity-framework

entity-framework-6