使用C＃mongo驅動程序構建查詢

Question

我不知道如何使用mongo驅動程序構建複雜查詢。這是我的查詢：

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(); 

隨着EFIQueryable此代碼工作正常，但我不能mongo driver建立正確的查詢。 誰能告訴我我做錯了什麼？

Answer 1

知道什麼finalExpression是有幫助的，以防出現問題。在我看來，有可能是與!(x.Promo == null && x.Promo == string.Empty)

MongoDB的驅動程序的翻譯，你可以試試下面的代碼，而不是你的，看它是否會有所作爲

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();