Question

我正在尝试动态构建一个IQueryable，它将测试以查看描述中是否存在多个字符串。

使用SQL可以通过多个OR语句轻松实现。

但我怎么能用LINQ做到这一点？

这是我到目前为止的代码......

List<string> keywords = new List<string>() { "BMW", "M3" };

IQueryable<AuctionVehicle> Results =
                from a in DBContext.tbl_Auction
                join v in DBContext.tbl_Vehicle on a.VehicleID equals v.VehicleID
                where v.Fuel.Equals(Fuel)
                && v.Transmission.Equals(Transmission)
                && a.EndDate < DateTime.Now
                select new AuctionVehicle()
                {
                    DB_Auction = a,
                    DB_Vehicle = v
                };

// Keywords
if (keywords.Count == 1)
{
    Results = Results.Where(x => x.DB_Auction.Description.Contains(keywords[0]));
}
else if (keywords.Count > 1)
{
    // ****************************
    // How can i add multiple OR statements??
    // ****************************
    Results = Results.Where(x => x.DB_Auction.Description.Contains(keywords[0]));
    foreach (string keyword in keywords)
    {
        Results = Results.Where(x => x.DB_Auction.Description.Contains(keyword));
    }
}

return Results;

Answer 1

您可以替换：

if (keywords.Count == 1)
{
    Results = Results.Where(x => x.DB_Auction.Description.Contains(keywords[0]));      
}
else if (keywords.Count > 1)
{
    Results = Results.Where(x => x.DB_Auction.Description.Contains(keywords[0])); 
    foreach (string keyword in keywords)
    {
        Results = Results.Where(x => x.DB_Auction.Description.Contains(keyword));
    }  
}

通过

Results = Results.Where(x => keywords.Any(y=>x.DB_Auction.Description.Contains(y)));

所以，最后你可能想在LINQ表达式中添加它：

where keywords.Any(x=>a.Description.Contains(x))

动态构建IQueryable OR语句

1 个答案: