Linq 单表城市级联

var list = (from province in db.Areas
where province.ParentId == 0 && province.IsDel == 0
join city in db.Areas on province.ID equals city.ParentId into citys
from ci in citys.DefaultIfEmpty()
join area in db.Areas on ci.ID equals area.ParentId into areas
select new
{
ID = province.ID,
Name = province.AreaName,
FullName = province.FullName,
Child = (from cy in citys
where cy.IsDel == 0
select new
{
ID = cy.ID,
Name = cy.AreaName,
FullName = cy.FullName,
Child = (from ar in areas
where ar.IsDel == 0
select new
{
ID = ar.ID,
Name = ar.AreaName,
FullName = ar.FullName,
})
})
}).ToList();
return list;