Question

此查询花了几天时间，但我几乎就在那里。我已经通过LINQ攻击实体，以便从阅读大量教程中得到以下内容。然而，这是我遗失的最后一部分。

我有两个基本对象：

public class DashboardNavigation()
{
   public int Id {get; set;}
   public string Name {get; set;}
   .....etc.....
   public List<SubNav> SubDashNav {get; set;}
}

public class SubNav()
{
   ....properties....
}




var query = _mlsDashboardNavRepository.Table
        .OrderBy(x => x.Id)
        .Select(x => new
        {
            Id = x.Id,
            Name = x.Name,
            Description = x.Description,
            ImageUrl = x.ImageUrl,
            SubDashNav = _mlsSubDashNav.Table
                .Where(s => s.DashId == x.Id)
                .Select(y => new { Id = y.Id, DashId = y.DashId, Name = y.Name, Description = y.Description, ImageUrl = y.ImageUrl, IsAdvanced = y.IsAdvanced }).ToList()

        }).ToList().Select(q => new MLS_DashboardNavigation()
                            {
                                Id = q.Id,
                                Name = q.Name,
                                Description = q.Description,
                                ImageUrl = q.ImageUrl,
                                SubDashNav = ...???

                            }).ToList();

我的Linq正确地投射DashboardNavigation，但我无法弄清楚如何填充SubDashNav ???

Answer 1

您无需选择两次。我认为这也是一样的。

var query = _mlsDashboardNavRepository.Table
    .OrderBy(x => x.Id)
    .Select(x => new MLS_DashboardNavigation()
    {
        Id = x.Id,
        Name = x.Name,
        Description = x.Description,
        ImageUrl = x.ImageUrl,
        SubDashNav = _mlsSubDashNav.Table
            .Where(s => s.DashId == x.Id).ToList()
    }).ToList();

如果您使用实体框架和导航属性将DashIs作为subNavDash表的外键，那么您甚至可以这样做

var query = _mlsDashboardNavRepository.Table
    .OrderBy(x => x.Id)
    .Select(x => new MLS_DashboardNavigation()
    {
        Id = x.Id,
        Name = x.Name,
        Description = x.Description,
        ImageUrl = x.ImageUrl,
        SubDashNav = x.SubDashNav
    }).ToList();

如果MLS_DashboardNavigation与_mlsDashboardNavRepository.Table的类型相同，那么您甚至不需要选择，因为它仍然是返回的。

var query = _mlsDashboardNavRepository.Table
    .OrderBy(x => x.Id).ToList()

Linq投影嵌套了LIST <t>属性

1 个答案: