c# - 在 C# 中使用 LINQ 的条件过滤器

Question

我需要获取记录列表并根据条件过滤它们:如果 serviceId = 1，那么我需要将该结果与 serviceId = 5 的结果相结合。

模型:

public class Partner
{
    [Key]
    public int Id { get; set; }
    public DbGeography Location { get; set; }
    public virtual ICollection<PartnerServiceBrand> PartnerServiceBrands { get; set; }
}

public class PartnerServiceBrand
{
    [Key]
    public int Id { get; set; }

    public virtual Partner Partner { get; set; }
    public virtual Service Service { get; set; }
}

public class Service
{
    [Key]
    public int Id { get; set; }
    public virtual ICollection<PartnerServiceBrand> PartnerServiceBrands { get; set; }
}

我的代码只有一个过滤器:

var serviceId = 1;

var partners = dbContext.Partners.Where(p => p.PartnerServiceBrands.Select(psb => psb.Service.Id).Contains(serviceId));

我尝试过:

if (serviceId == 1)
{
    var partners2 = dbContext.Partners.Where(p => p.PartnerServiceBrands.Select(psb => psb.Service.Id).Contains(5));

    partners = partners.Union(partners2);  // Error
}

我也尝试使用 Contains用List<int> ，但我无法启动并运行它。

编辑

我得到的错误是:

Exception:Thrown: "The geography data type cannot be selected as DISTINCT because it is not comparable." (System.Data.SqlClient.SqlException)

Answer 1

我对此的看法。

给定要过滤的 serviceIds 列表:

var serviceIds = new List<int>{1, 5};

var partners = dbContext.Services
    .Where(ser => serviceIds.Contains(ser.Id).SelectMany(ser => ser.PartnerServiceBrands)
    .Select(psb => psb.Partner).Distinct();