wpf 查询实体框架 6 中的多列
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Querying against multiple columns in Entity Framework 6
提问by UnbiasedMilo
I'm trying to execute a query against multiple columns in EF 6 (using C# WPF on VS 2013), I need to select all fields of some columns. I really don't know much but I already tried to do it with Linq and it doesn't seem to have that functionality, so I went with <context>.Database.SqlQuery<string>(query), but it's unclear to me how should I handle what it returns. The query is something simple like "SELECT column1,column2 FROM table".
我正在尝试对 EF 6 中的多个列执行查询（在 VS 2013 上使用 C# WPF），我需要选择某些列的所有字段。我真的不太了解，但我已经尝试用 Linq 来做它，它似乎没有那个功能，所以我去了<context>.Database.SqlQuery<string>(query)，但我不清楚我应该如何处理它返回的内容。查询很简单，例如"SELECT column1,column2 FROM table".
Is it possible to do it with Linq? How? And for the SqlQuery()case, How should I handle it's result, being most of its columns are in string format?
有可能做到Linq吗？如何？对于这种SqlQuery()情况，我应该如何处理它的结果，因为它的大部分列都是字符串格式？
回答by Harshana Narangoda
@MiloGP yes you can do it with using Lambda Expression with LINQ
@MiloGP 是的，您可以通过在 LINQ 中使用 Lambda 表达式来实现
Here a example:
这里有一个例子：
I have 5 columns in table employee(emp_id,emp_name,emp_dob,emp_address,emp_reference)
我在表员工（emp_id，emp_name，emp_dob，emp_address，emp_reference）中有 5 列
and My DBContext name : EmployeeEntities;
和我的 DBContext 名称：EmployeeEntities；
I trying to get emp_name and emp_address
我试图获得 emp_name 和 emp_address
List<employee> = EmployeeEntities.employees.select( x => new { x.emp_name, x.emp_address }).ToList();
List<employee> = EmployeeEntities.employees.select( x => new { x.emp_name, x.emp_address }).ToList();
if you need to get value of someone, As a example emp_id == 13458
如果您需要获取某人的价值，例如 emp_id == 13458
List<employee> = EmployeeEntities.employees.Select( x => new { x.emp_name, x.emp_address }).Where( y => y.emp_id == 13458).ToList();
List<employee> = EmployeeEntities.employees.Select( x => new { x.emp_name, x.emp_address }).Where( y => y.emp_id == 13458).ToList();
