Linq to SQL / C#：如何使用交叉引用表中的属性和 lambda 表达式进行排序

发布于 2024-09-06 06:28:38 字数 718 浏览 1 评论 0原文

我试图根据交叉引用表的 zindex 属性与类别表（在本例中称为“机箱”）来订购产品列表，但出现以下错误：

无法按类型“System”订购。 Collections.Generic.IEnumerable`1[System.Int32]'。

以下是我正在使用的方法：

public IQueryable<E_Product> Product_GetList_ByChassisId(int chassisId)
{
    return dc.E_Products
        .Where(x => x.Deleted == false)
        .Where(x => x.Published == true)
        .Where(x => x.E_Product_Chassis
            .Any(c => c.ChassisId == chassisId && c.Deleted == false))
        .OrderBy(x => x.E_Product_Chassis.Select(c => c.Zindex));
}

我了解 .Select 方法返回 IEnumerable，但作为多对多关系，x.E_Product_Chassis不允许简单选择其属性（例如xE_Product_Chassis.Zindex）。

任何帮助将不胜感激...

原文

I am trying to order a list of products based on the zindex property of the cross reference table with the category table (in this case called 'Chassis'), but I get the following error:

Cannot order by type 'System.Collections.Generic.IEnumerable`1[System.Int32]'.

The following is the method I am using:

public IQueryable<E_Product> Product_GetList_ByChassisId(int chassisId)
{
    return dc.E_Products
        .Where(x => x.Deleted == false)
        .Where(x => x.Published == true)
        .Where(x => x.E_Product_Chassis
            .Any(c => c.ChassisId == chassisId && c.Deleted == false))
        .OrderBy(x => x.E_Product_Chassis.Select(c => c.Zindex));
}

I understand the .Select method returns an IEnumerable, but being a many-to-many relationship, x.E_Product_Chassis does not allow simple selection of its properties (e.g. x.E_Product_Chassis.Zindex).

Any help would be very appreciated...

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水中月 2024-09-13 06:28:38

FirstOrDefault()、Min()、Max()——使用这些函数之一从集合中选择适当的 z 索引。

public IQueryable<E_Product> Product_GetList_ByChassisId(int chassisId) 
{ 
    return dc.E_Products 
        .Where(x => x.Deleted == false) 
        .Where(x => x.Published == true) 
        .Where(x => x.E_Product_Chassis 
            .Any(c => c.ChassisId == chassisId && c.Deleted == false)) 
        .OrderBy(x => x.E_Product_Chassis.Min(c => c.Zindex)); 
}

FirstOrDefault(), Min(), Max() -- use one of these functions to select the appropriate z-index out of the set.

public IQueryable<E_Product> Product_GetList_ByChassisId(int chassisId) 
{ 
    return dc.E_Products 
        .Where(x => x.Deleted == false) 
        .Where(x => x.Published == true) 
        .Where(x => x.E_Product_Chassis 
            .Any(c => c.ChassisId == chassisId && c.Deleted == false)) 
        .OrderBy(x => x.E_Product_Chassis.Min(c => c.Zindex)); 
}

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