在EF中选择单个列

Question

如何选择单个列而不是执行select l ?

IEnumerable<LEA> query = default(IEnumerable<LEA>);
var query = from l in bModel.leas
            join la in bModel.LondonAreas on l.LEANo equals la.LeaNo
            where la.AreaNo == areaNo
            select l;

Answer 1

匿名对象是选择特定列的方法

IEnumerable<LEA> query = default(IEnumerable<LEA>);
var query = from l in bModel.leas
    join la in bModel.LondonAreas on l.LEANo equals la.LeaNo
    where la.AreaNo == areaNo
    select new
    {
        LEANo = l.LEANo,
        AreaNo = la.AreaNo
    };

Answer 2

您可以在查询的'select'部分创建一个包含所需属性的匿名对象。

一样:

IEnumerable<LEA> query = default(IEnumerable<LEA>);
var query = from l in bModel.leas
            join la in bModel.LondonAreas on l.LEANo equals la.LeaNo
            where la.AreaNo == areaNo
            select new { LEANo = l.LEANo };