ef core报错“A second operation was started on this context instance before a previous operation completed. This is usually caused by different threads concurrently using the same instance of DbContext.”

环境：

asp .net core 6

ef core

 

代码报错：

 

 

 #region 删除教师
        [HttpPost]
        public async Task<IActionResult> Delete(int id)
        {
            var teacher = _teacherRepository.FirstOrDefaultAsync(a => a.Id == id);

            if (teacher == null)
            {
                ViewBag.ErrorMessage = $"教师编号{id}的信息不存在，请重试。";
                return View("NotFound");
            }

            await _officeRepository.DeleteAsync(a=>a.TeacherId==teacher.Id);
            await _courseAssignmentRepository.DeleteAsync(a => a.TeacherID == teacher.Id);
            await _teacherRepository.DeleteAsync(a=>a.Id==teacher.Id);
            return RedirectToAction(nameof(Index));
        }
        #endregion 删除教师

 

 

解决方案：

将方法的每个数据库操作都await，如下图：

 

 

 

 

有关如何避免 DbContext 线程问题的详细信息，请参考链接：https://docs.microsoft.com/zh-cn/ef/core/dbcontext-configuration/#avoiding-dbcontext-threading-issues