使用 C# mongo 驱动程序构建查询

Question

我想知道如何使用 mongo 驱动程序构建复杂的查询。这是我的查询：

var builder = Builders<MongoNavFilter>.Filter;
var query = builder.Where(x => x.Link == link && x.SubLink == subLink);
if (some statement)
{
    var finalExpression = ...
    query = query & Builders<MongoNavFilter>.Filter.Where(finalExpression); 
}
if (onsale)
    query = query & Builders<MongoNavFilter>.Filter.Where(x => !(x.Promo == null && x.Promo == string.Empty));

var filters = _db.GetCollection<MongoNavFilter>("NavFilters").
                    Find(query).ToList();

这段EF IQueryable代码工作正常，但我无法使用mongo driver. 谁能告诉我我做错了什么？

Answer 1

知道问题finalExpression所在会有所帮助，以防出现问题。我认为mongodb驱动的翻译可能有问题!(x.Promo == null && x.Promo == string.Empty)

您可以尝试以下代码而不是您的代码，看看是否会有所不同

var builder = Builders<MongoNavFilter>.Filter;
var query = builder.Eq(x => x.Link, link) & builder.Eq(x=> x.SubLink, subLink);
if (some statement)
{
    var finalExpression = ... // write this using the same syntax 
    query = query & filter; 
}
if (onsale)
    query = query & builder.Ne(x=>x.Promo, null) & builder.Ne(x=> x. Promo, string.Empty);

var filters = _db.GetCollection<MongoNavFilter>("NavFilters").
                Find(query).ToList();