我的实体模型：

public class Person
{
  [Key]
  [DatabaseGenerated(DatabaseGeneratedOption.None)]
  public int Id { get; set; }

  public int Name { get; set; }
}

脚步：

1)我将此实体person1的实例(Id = 1)插入到我的人员表中.

using (var context = new MyDbContext())
{
   context.Create(person1);
   await context.SaveChangesAsync();
}

2)在一些书籍后,我用以下内容清除整个人员表：

using (var context = new MyDbContext())
{
   await context.Database.ExecutesqlCommandAsync(string.Format("DELETE FROM `PersonModels`"));
   await context.SaveChangesAsync();
}

3)我尝试添加与第一步中的条目相同的主键：person2(Id = 1)

using (var context = new MyDbContext())
{
   context.Create(person2);
   await context.SaveChangesAsync();
}

但是在第3步中,SaveChangesAsync()失败了

System.InvalidOperationException: The changes to the database were committed successfully,but an error occurred while updating the object context. The ObjectContext might be in an inconsistent state. Inner exception message: Saving or accepting changes Failed because more than one entity of type ‘DbModels.PersonModel’ have the same primary key value.

当我在清除表(使用不同的主键)之后添加一些其他条目然后从第1步添加条目时,它工作正常并且两个条目都保存,没有例外.

我在创建新条目之前直接添加了断点(在清除表之后)并通过外部工具检查了Persons表,并且表是空的(因此没有id = 1的条目).

更新：
我的Create方法的扩展DbContexte实现：

public DbSet<PersonModel> Persons { get; set; }

    public T Create<T>(T entity)
        where T : class
    {
        try
        {
            GetDbSetForType<T>().Add(entity);
            return entity;
        }
        catch (Exception ex)
        {
            return default(T);
        }
    }

    private DbSet<T> GetDbSetForType<T>()
        where T : class
    {
        var type = typeof(T);

        if (type == typeof(PersonModel)) return Persons as DbSet<T>;
        //...my other types
        throw new Exception("Type not found in db");
    }