计划将项目中使用entity framework的要点记录到改栏目下

ef监控sql执行性能日志。http://www.cnblogs.com/CreateMyself/p/5277681.html

http://123.122.205.38/cn_sql_server_2008_r2_enterprise_x86_x64_ia64_dvd_522233.iso?fid=hqkUfQCwLLgefGdBiOC73ps1JxMA*O0VAQAAAGT1XOywsz1scWyaiQsnM*YF3JxX&mid=666&threshold=150&tid=E644E3AB354940E901996D7CF1F47CF9&srcid=119&verno=1

今天在做毕业设计时，遇到了一个很郁闷的问题:

public partial class ProjectModule : Entity
    {
        public ProjectModule()
        {
            Id = GuidComb.GenerateComb();
        }

        public Guid Id { get; set; }
        public string Name { get; set; }
        public int Grade { get; set; }
        public int DisplayOrder { get; set; }
        public string FullPathName { get; set; }

        public virtual Project Project { get; set; }
        public virtual ProjectModule Parent { get; set; }
    }

 我是用函数获取对象，对其进行修改：

        public ProjectModule GetById(Guid id)
        {
            return _context.ProjectModule
                .FirstOrDefault(m => m.Id == id);
        }

之后调用对象对其修改：

    [HttpPost]
        public JsonResult Modify(ProjectModuleViewModel model)
        {
            using (var unitOfWork = UnitOfWorkManager.NewUnitOfWork())
            {
                AjaxResult result = new AjaxResult();

                ProjectModule module = _projectModuleService.GetById(model.Module_Id.Value);
                if (model.Module_IsDelete == 1)
                {
                    try
                    {
                        _projectModuleService.Delete(module);
                        unitOfWork.Commit();

                        result = new AjaxResult() { status = AjaxResultStatus.success, detail = "删除成功！" };
                    }
                    catch (Exception ex)
                    {
                        unitOfWork.Rollback();
                        LoggingService.Error(ex);
                        result = new AjaxResult() { status = AjaxResultStatus.failed, detail = "删除失败！" };
                    }

                    return Json(result);
                }

                module.DisplayOrder = model.Module_DisplayOrder;
                module.Name = model.Module_Name;

                Project project = _projectService.GetById(model.Module_ProjectId);               
                module.Project = project;

                if (string.IsNullOrEmpty(model.Module_Name))
                {
                    result = new AjaxResult() { status = AjaxResultStatus.failed, detail = new Dictionary<string, string>() };
                    result.AddDetailItem("Module_Name", "请填写模块名");
                    return Json(result);
                }

                if (model.Module_ParentId.HasValue == false)
                {
                    module.FullPathName = model.Module_Name;
                    module.Parent = null;
                    module.Grade = 0;
                }
                else
                {
                    if (model.Module_ParentId.Value == model.Module_Id)
                    {
                        result = new AjaxResult() { status = AjaxResultStatus.failed, detail = new Dictionary<string, string>() };
                        result.AddDetailItem("Module_ParentId", "节点自己不允许作为自己的子节点！");
                        return Json(result);
                    }
                    ProjectModule parent = _projectModuleService.GetById(model.Module_ParentId.Value);

                    module.FullPathName = parent.FullPathName + "/" + model.Module_Name;
                    module.Parent = parent;
                    module.Grade = parent.Grade + 1;
                }

                try
                {
                    unitOfWork.Commit();

                    result = new AjaxResult() { status = AjaxResultStatus.success, detail = "保存成功！" };
                }
                catch (Exception ex)
                {
                    unitOfWork.Rollback();
                    LoggingService.Error(ex);
                    result = new AjaxResult() { status = AjaxResultStatus.failed, detail = "保存失败！" };
                }

                return Json(result);
            }
        }

其中代码执行了 module.Parent=null之后，发现并没有把Parent对象真的赋值为null,但我修改了之后发现其他字段都已经修改了，后来发现parent字段在数据库中依然存在有值。

后来尝试了使用我尝试修改啦GetById（）函数后，发现问题解决了。

修改为：

  public ProjectModule GetById(Guid id)
        {
            return _context.ProjectModule
                .Include(x => x.Parent)
                .FirstOrDefault(m => m.Id == id);
        }