c# - 如何使用列表查询查找表？

Question

鉴于下面的类，我希望能够使用 ID 列表返回 DesignAttribute 表中 AttributeId 为 1 或 3 的设计。

public class Design
{
    public int DesignId { get; set; }
    public string DesignName { get; set; }
    public virtual List<DesignAttribute> DesignAttributes { get; set;}
}

public class Attribute
{
    public int AttributeId { get; set; }
    public string AttributeName { get; set; }
}

public class DesignAttribute
{
    public int DesignAttributeId { get; set; }
    public virtual Design Design { get; set; }
    public virtual Attribute Attribute { get; set; }
}

一个设计可以有一个或多个属性，例如

设计表

DesignId    DesignName
1           Design A
2           Design B
3           Design C

属性表

AttributeId     AttributeName
1               Light
2               Dark
3               Demo

设计属性表

DesignAttributeId   Design_DesignId     Attribute_AttributeId
1                   1                   1               Design A is Light 
2                   1                   3               Design A is also a Demo 
3                   2                   2               Design B is Dark
4                   3                   1               Design C is Light

我有以下代码

//attributes list = "[1,3]  I want any designs that have  Light OR Demo attributes"
public List<Design> FilterDesigns(List<string> attributes)
{
    //sudo code as i'm not sure how to structure this.
    var designs = db.Designs.Where(i => i.DesignAttributes 
    WHERE     DesignAttributes.AttributeId is in the list of attributes passed into the method) 
}

因此，我希望最终得到包含设计 A 和设计 C 的 2 个项目的列表，因为它们在 DesignAttribute 查找表中都有一个针对属性 ID 1 和 3 的 ID。

Answer 1

试试这个:

var designs = db.Designs.Where(design => 
                  design.DesignAttributes.Any(designAttribute => 
                   attributes.Contains(designAttribute.Attribute.AttributeId)))
              .ToList();