实体框架不处理对组合键的更改

Question

我有一个多对多关系的课程，如下：

public partial class AdminBoundaryStaff 
{
    [Key, Column(Order=0)]
    public int idAdminBoundary { get; set; }
    [Key, Column(Order = 1)]
    public int idAdminStaff { get; set; }
    [Key, Column(Order = 2)]
    public int idAdminStaffType { get; set; }

    public virtual AdminBoundary AdminBoundary { get; set; }
    public virtual AdminStaff AdminStaff { get; set; }
    public virtual AdminStaffType AdminStaffType { get; set; }

如果我更改了idAdminStaff的值并将表单发回给控制器，则EF似乎没有看到更改，甚至没有尝试SQL更新（使用分析器观察它）。 / p>

    [HttpPost]
    public ActionResult Edit( AdminBoundaryStaff adminboundarystaff)
    {
        if (ModelState.IsValid)
        {
            db.Entry(adminboundarystaff).State = EntityState.Modified;
            db.SaveChanges();
            return RedirectToAction("Index");
    }}