实体框架 - 如何保存多个更改（添加，更新，删除）到DB（主数据） [英] Entity Framework - how to save multiple changes (add, update, delete) to DB (Master detail)

问题描述

我的项目是Windows应用程序c＃，我正在使用实体框架5和.net 4.5。

我有房间和床模块，您可以添加，编辑和删除房间和/或床位在我的窗体上我有一个RoomNo和Station的字段，还有添加和删除按钮添加/删除床（s） ）到datagridview，然后保存按钮保存房间和床单列表

  DB结构
 
房间（表）
 PK_Rooms 
 FK_Station 
房间没有
 
床（桌子）
 PK_Beds 
 FK_Rooms 
 BedNo 
 FullRoomNo（仅限Roomno和Bedno）
 RoomStatus 
  

我已经实现了AddRoom 方法将创建新房间和床单列表。

我的问题是如何实现EditRoom方法，它将检测床上的变化（添加一个新床，和/或编辑床号，和/或删除床）并将其保存到数据库？

更好地了解我的关心请求e看到以前的线程，其中还有AddRoom方法>
实体框架只保存最后一行（主要细节）

编辑：
这里是我的代码到EditRoom方法

  M3dEntities m3d = new M3dEntities（）; 
 rooms rooms =新房（）; 
床位=新床（）; 
 string RoomNo = RoomNoTxt.Text; 
 int StationID = Int32.Parse（StationCmb.SelectedValue.ToString（））; 
 int _SelectedPKRoom = Int32.Parse（SelectedPKRoom）; 
 rooms = m3d.rooms.First（x => x.PK_Rooms == _SelectedPKRoom）; 
 {
 rooms.RoomNo = RoomNo; 
 rooms.FK_Stations = StationID; 
} 
 
 
 foreach（BedsDataGridView.Rows中的DataGridViewRow行）
 {
床=新床（）; 
 beds.Bedno = row.Cells [0] .Value.ToString（）; 
 beds.FullRoomNo = row.Cells [1] .Value.ToString（）; 
 beds.RoomStatus =可用; 
 m3d.beds.AddObject（床）; 
 m3d.beds.DeleteObject（床）; 
} 
 
 m3d.SaveChanges（）; 
  

此代码的问题只是正在更新的空间：（

解决方案

这是一种方式，我希望它可以帮助你

  var room =（from g in m3d.rooms 
其中g.RoomNo == RoomNo 
 select g）.FirstOrDefault（）; //取一个objecto空间修改
 room.FK_Stations = StationID; 
 foreach（BedsDataGridView.Rows中的DataGridViewRow行）
 {
 
 int Bedno = row.Cells [0] .Value.ToString（）; 
 
 var bedsChanged =（from g in m3d.beds 
其中g.bedno == Bedno 
选择g）.FirstOrDefault（）; 
 
 bedsChanged.FullRoomNo = row.Cells [1] .Value.ToString（）; 
 bedsChanged.RoomStatus =Available; 
 
} 
 m3d.SaveChanges（）; 
  

My project is Windows Application c#, I am using Entity Framework 5 and .net 4.5.

I have Rooms and Beds module which you can add, edit and delete Room(s) and/or bed(s)

on my Form I have a field for RoomNo and Station, also Add and Delete button to add/delete bed(s) to datagridview, then Save button to save the Room and list of beds to DB

DB Structure

Rooms (table)
PK_Rooms
FK_Station
RoomNo

Beds (table)
PK_Beds
FK_Rooms
BedNo
FullRoomNo (concat only of Roomno and Bedno)
RoomStatus

I already implemented the "AddRoom" method which will create new Room and list of beds.

my question is how can i implement "EditRoom" method which will detect changes on the beds (added a new bed, AND/OR edited a bed number, AND/OR deleted a bed) and save it to DB?

To have a better understanding to my concern please see previous thread, which also has the AddRoom Method > Entity Framework only saving last row (master details)

Edit: here is my code to EditRoom method

        M3dEntities m3d = new M3dEntities();
        rooms rooms = new rooms();
        beds beds = new beds();
        string RoomNo = RoomNoTxt.Text;
        int StationID = Int32.Parse(StationCmb.SelectedValue.ToString());
        int _SelectedPKRoom = Int32.Parse(SelectedPKRoom);
        rooms = m3d.rooms.First(x => x.PK_Rooms == _SelectedPKRoom);
        {
            rooms.RoomNo = RoomNo;
            rooms.FK_Stations = StationID;
        }


        foreach (DataGridViewRow row in BedsDataGridView.Rows)
        {
            beds = new beds();
            beds.Bedno = row.Cells[0].Value.ToString();
            beds.FullRoomNo = row.Cells[1].Value.ToString();
            beds.RoomStatus = "Available";
            m3d.beds.AddObject(beds);
            m3d.beds.DeleteObject(beds);
        }

        m3d.SaveChanges();

the problem with this code is only room are being updated :(

解决方案

This is one Way, I hope it helps you

              var room= (from g in m3d.rooms
                      where g.RoomNo == RoomNo
                      select g).FirstOrDefault(); //Take an objecto room to modify 
    room.FK_Stations = StationID;
   foreach (DataGridViewRow row in BedsDataGridView.Rows)
   {

      int Bedno = row.Cells[0].Value.ToString();

      var bedsChanged= (from g in m3d.beds
                      where g.bedno== Bedno
                      select g).FirstOrDefault(); 

      bedsChanged.FullRoomNo = row.Cells[1].Value.ToString();
      bedsChanged.RoomStatus = "Available";

    }
     m3d.SaveChanges();

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