MVC +EF+linq 多表聯查

關於linq的多表聯查效果的實現：

后台多表查詢  內連接：

SELECT
[Extent2].[partID] AS [partID],
[Extent1].[userName] AS [userName],
[Extent3].[partName] AS [partName]
FROM [dbo].[User] AS [Extent1]
INNER JOIN [dbo].[User_partB] AS [Extent2] ON [Extent1].[userGUID] = [Extent2].[userGUID]
INNER JOIN [dbo].[partB] AS [Extent3] ON [Extent2].[partID] = [Extent3].[partID]

數據庫數據效果展示：

代碼如下：

 

  var userListTest = (from u in db.Users
                                join p in db.User_partB on u.userGUID
              equals p.userGUID
                                join d in db.partBs on p.partID equals d.partID
                                select new { name = u.userName, departName = d.partName });
            List<dynamic> oneList = new List<dynamic>();
            foreach (var one in userListTest.ToList())
            {
                dynamic dyObject = new ExpandoObject();
                dyObject.userName = one.name;
                dyObject.departName = one.departName;
                oneList.Add(dyObject);
            }
            ViewBag.dyObject = oneList;
            return View();

前台數據展現效果：

<table>
    <tr><td>用戶登錄名</td><td>姓名</td><td>狀態</td><td>角色</td><td>操作</td></tr>
    @{foreach (var one in ViewBag.dyObject)
    {
        <tr>
            @*<td>@one.userLoginName</td>*@
            <td>@one.userName</td>
            @*<td>@one.active==1?"啟用":"禁用"</td>*@
            <td>@one.departName</td>
            <td></td>
        </tr>
    }
    }
</table>

linq  多表聯查 外鏈接：

SELECT
1 AS [C1],
[Extent1].[userName] AS [userName],
[Extent3].[partName] AS [partName]
FROM [dbo].[User] AS [Extent1]
LEFT OUTER JOIN [dbo].[User_partB] AS [Extent2] ON [Extent1].[userGUID] = [Extent2].[userGUID]
LEFT OUTER JOIN [dbo].[partB] AS [Extent3] ON [Extent2].[partID] = [Extent3].[partID]

數據庫數據展示效果：

代碼如下：

 var userListTest = (from u in db.Users
                                join p in db.User_partB on u.userGUID
              equals p.userGUID into temp
                                from t in temp.DefaultIfEmpty()
                                join d in db.partBs on t.partID equals d.partID 
                                into tempone
                                from user in tempone.DefaultIfEmpty()
                                select new { name = u.userName, departName = user.partName });
            List<dynamic> oneList = new List<dynamic>();
            foreach (var one in userListTest.ToList())
            {
                dynamic dyObject = new ExpandoObject();
                dyObject.userName = one.name;
                dyObject.departName = one.departName;
                oneList.Add(dyObject);
            }
            ViewBag.dyObject = oneList;
            return View();

前台數據展示效果同上

上述過程中，遇到  延遲加載后的動態數據，TOList()之后，傳遞到前台后，在foreach循環時，無法通過對象.屬性的形式，讀取出來，報“OBJECT未定義該屬性”，經過查找原因發現，該動態數據為internal類型，只能同一程序集內訪問，找了若干方法，不太適用，當然，如果大家有好的建議，可以一起交流討論，究於當前場景，我選擇了ExpandoObject，來動態處理，linq的查詢結果。