linq 根据IQueryable中的多个枚举值检查值

hxzsmxv2 于 2022-12-06 发布在其他

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我正在尝试编写一个优雅的解决方案，在一个IQueryable中针对多个枚举值过滤一个值。

分机号

public static class EnumExtensions
{
    public static bool IsAny<T>(this T value, params T[] choices)
    where T : Enum
    {
        return choices.Contains(value);
    }
}

用法

query = query.Where(x => x.Status.IsAny(OrderStatus.Accepted, OrderStatus.Received, OrderStatus.Approved));

但是当我执行这个命令时，我得到了以下错误：

An unhandled exception has occurred while executing the request.
System.InvalidOperationException: The LINQ expression 'DbSet<SalesOrder>
.Where(s => s.DeletedAt == null)
.Where(s => False || s.SellerId == __request_OwnerId_0)
.Where(s => s.Status
    .IsAny(OrderStatus[] { Accepted, Received, Approved, }))' could not be translated. Either rewrite the query in a form that can be translated, or switch to client evaluation explicitly by inserting a call to either AsEnumerable(), AsAsyncEnumerable(), ToList(), or ToListAsync(). See https://go.microsoft.com/fwlink/?linkid=2101038 for more information.

有什么建议吗？

linq

来源：https://stackoverflow.com/questions/74076757/check-value-against-multiple-enum-values-in-iqueryable

1条答案

按热度按时间

31moq8wy1#

你不能在Linq查询和EF的Expression<>参数中使用自定义方法。你需要用长格式的方法来实现：

query = query
    .Where( x =>
        x.Status == OrderStatus.Accepted ||
        x.Status == OrderStatus.Received ||
        x.Status == OrderStatus.Approved
    );

根据您的RDBMS，您 * 也许 * 可以这样做：

static readonly OrderStatus[] _these = new[] { OrderStatus.Accepted, OrderStatus.Received, OrderStatus.Approved };

// ...

query = query.Where( x => _these.Contains( x.Status ) );

...应转换为以下SQL：

WHERE
    x.Status IN ( 0, 1, 2 )

（假设OrderStatus.Accepted == 0、Received == 1、Approved == 2）。

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linq 根据IQueryable中的多个枚举值检查值

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