asp.net-mvc - 从我的数据库上下文中删除基于 id 的用户

Question

我正在尝试为用户实现基本的删除操作方法：

    private User_Manager_Interface.Models.ApplicationDbContext userDb = new User_Manager_Interface.Models.ApplicationDbContext();
    // POST: /Users/Delete/5
    [HttpPost]
    public ActionResult Delete(int id, FormCollection collection)
    {
        try
        {
            // TODO: Add delete logic here

                //.Remove(u => u.id == id);
            return RedirectToAction("Index");
        }
        catch
        {
            return View();
        }
    }

我不完全确定如何删除用户。

这是我到目前为止所尝试的：

  userDb.Users.Remove();  But now I don't know how to tell it to delete the user with a certain ID?

我该怎么做呢？

Answer 1

假设您userDb是DbContext（不是ObjectContext）有几种方法可以实现您的目标。您可以通过以下方式执行此操作：

var user = userDb.Users.FirstOrDefault(u => u.UserId == id);
if(user != null)
{
    userDb.Users.Remove(user); 
}

或者你可以这样做：

var user = userDb.Users.FirstOrDefault(u => u.UserId == id);
if(user != null)
{
    userDb.Entry(user).State= EntityState.Deleted;
    userDb.SaveChanges();
}

Answer 2

查看本教程 -删除实体框架中的实体

教程中的示例代码 -

  using (var dbCtx = new SchoolDBEntities())
        {

            //if already loaded in existing DBContext then use Set().Remove(entity) to delete it.
            var newtchr = dbCtx.Teachers.Where(t => t.TeacherName == "New teacher4")
                                .FirstOrDefault<Teacher>();
            dbCtx.Set(Teacher).Remove(newtchr);

            //Also, you can mark an entity as deleted
            //dbCtx.Entry(tchr).State = System.Data.EntityState.Deleted;    

            //if not loaded in existing DBContext then use following.
            //dbCtx.Teachers.Remove(newtchr);

            dbCtx.SaveChanges();
        }