编程小技巧:输入for,foreach,cw...然后按两次tab键能快速产生代码
EntityCollection的using指令是:using System.Data.Objects.DataClasses; ObjectQuery的using指令是:using System.Data.Objects; 主表来映射时应该映射到外键表。 ObjectContext---DataAdapter ObjectQuery-----Dataset IQueryable<DBItemList> list = context.DBItemList.OrderBy(p=>p.ItemValue); //IQueryable<T>可以用来进行数据筛选或其他运算 static void Main(string[] args) { WanceMISEntities MISData = new WanceMISEntities(); //ObjectQuery<Department> department_list = MISData.Department;//从主键表访问数据 //foreach(Department department_Entity in department_list) //{ // Console.WriteLine("{0},{1}",department_Entity.DepartmentID,department_Entity.DepartmentName); // EntityCollection<DepartmentUser> departmentuser_list = department_Entity.DepartmentUser_1; // departmentuser_list.Load();//加载外键数据 // foreach (DepartmentUser departmentuser_Entity in departmentuser_list) // { // Console.WriteLine("{0},{1}",departmentuser_Entity.DepartmentUserID,departmentuser_Entity.DepartmentUserState); // }
//}
//ObjectQuery<DepartmentUser> departmentuser_list = MISData.DepartmentUser;//从外键表访问数据 //foreach (DepartmentUser departmentuser_Entity in departmentuser_list) //{ // Console.WriteLine("{0},{1}",departmentuser_Entity.DepartmentUserID,departmentuser_Entity.DepartmentUserState); // departmentuser_Entity.Department_1Reference.Load(); // Department department = departmentuser_Entity.Department_1; // Console.WriteLine("{0},{1}",department.DepartmentID,department.DepartmentName); //} //var v = MISData.Department.First(s=>s.DepartmentID=="1");//删除主键 //要删除主键时,要保证内存中对应的外键数据为空 //v.DepartmentUser_1.Load(); //if (v.DepartmentUser_1.Count != 0) //{ // List<DepartmentUser> departmentuser = new List<DepartmentUser>(); // foreach (var w in v.DepartmentUser_1) // { // departmentuser.Add(w); // } // foreach (var item in departmentuser) // { // MISData.DeleteObject(item); // } //} //MISData.DeleteObject(v); //MISData.SaveChanges(); //DepartmentUser departmentuser = new DepartmentUser();//直接插入外键数据 //departmentuser.AccountID = "1"; //departmentuser.DepartmentUserID = "1"; //departmentuser.DepartmentUserState =1; //departmentuser.Department_1 = MISData.Department.First(s=>s.DepartmentID=="1");//要有主键信息 //MISData.AddToDepartmentUser(departmentuser); //MISData.SaveChanges(); //通过主键插入外键数据 //var tab1 = MISData.Department.First(s=>s.DepartmentID=="1"); //DepartmentUser tab2 = new DepartmentUser(); //tab2.AccountID = "1"; //tab2.DepartmentUserID = "1"; //tab2.DepartmentUserState = 1; //tab1.DepartmentUser_1.Add(tab2); //MISData.SaveChanges(); }
|
|