我如何使用EntityDatasource(或使用LinqDataSource)与欧盟条款 [英] How do I use EntityDatasource (Or LinqDatasource) with a Union clause
问题描述
如何合并两个表中的记录在EntityDataSource控件?我用Google搜索它,没有运气SO搜查。什么,我需要在SQL是
How do I combine records from two tables in an Entitydatasource control? I have googled it and searched on SO with no luck. The SQL of what I need is
SELECT DISTINCT username FROM
(SELECT s.username FROM project_stakeholders s
UNION
SELECT t.username FROM project_team_members t)
我的实体结构如下:
My entities structure is as follows:
project_stakeholders
----------------------
project_stakeholders.record_id (PK)
project_stakeholders.username
project_stakeholders.project
project_stakeholders.project_id (FK)
project_stakeholders.status
project_team_members
---------------------
project_team_members.record_id (PK)
project_team_members.username
project_team_members.project
project_team_members.project_id (FK)
project_team_members.status
我发现这个问题,几乎提供了一个回答我的问题,但我的是更先进的,因为我的子查询从没有涉及到的主要实体的实体。
I found this question that almost provides an answer to my question but mine is more advanced because my SubQueries are from Entities not related to the primary entity.
我已经改变了我的数据源LiqDatasource控制在code LinqDataSource控件的Onselecting事件背后添加了code如下:
I have changed my Datasource to LiqDatasource Control and added the code below in the Code Behind of the Onselecting Event of the LinqDatasource Control:
protected void TaskProfileDS_Selecting(object sender, LinqDataSourceSelectEventArgs e)
{
int project_id = 0;
if (Int32.TryParse(Request.QueryString["id"], out project_id))
{
using (MyEntitiesContext db = new MyEntitiesContext())
{
var TeamMembers = from tm in db.team_members where tm.project_id == project_id select tm.username;
var Stakeholders = from sh in db.project_stakeholders where sh.project_id == project_id select sh.username;
var result = from usr in db.project_profiles where (TeamMembers.Contains(usr.caption) || Stakeholders.Contains(usr.caption)) select usr;
e.Result = result;
}
}
}
但不幸的是,我得到以下错误:
But unfortunately, I get the following error:
操作无法完成。
任何想法将大大AP preciated。
any ideas will be greatly appreciated.
推荐答案
下面是code,它为我工作来从不相关的表(实体)的记录。我用的LinqDataSource,然后在QueryCreated事件中,我改变了查询,以我自己的LINQ查询:
Here is the code that worked for me to fetch records from unrelated tables (entities). I used LinqDataSource, then in the QueryCreated event, I changed the query to my own LINQ query:
protected void TaskDS_QueryCreated(object sender, QueryCreatedEventArgs e)
{
int project_id = 0;
if (Int32.TryParse(Request.QueryString["id"], out project_id))
{
using (SDManagerEntities db = new SDManagerEntities())
{
List<project_profiles> usrs = new List<project_profiles>();
var users1 = db.team_members.Where(t => t.project_id == project_id).Select(it => it.username);
var users2 = db.project_stakeholders.Where(s => s.project_id == project_id).Select(it => it.username);
var allMembers = users1.Concat(users2);
foreach (var member in allMembers.Distinct())
{
project_profiles usr = db.project_profiles.SingleOrDefault(it => it.caption == member);
if (!usrs.Contains(usr))
{
usrs.Add(usr);
}
}
e.Query = usrs.AsQueryable().OrderBy(it => it.fullName);
}
}
}
我希望它能帮助别人
I hope it helps someone else
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