查询mongodb集合为动态 [英] Query mongodb collection as dynamic

问题描述

我将dynamic对象保存在数据库中，但我也想将其检索为动态对象.如何才能做到这一点?我这样尝试过:

I'm saving a dynamic object in my database but I would also like to retrieve it as a dynamic object. How can this be done? I tried it like so:

public dynamic GetItemById(ObjectId id)
{
    dynamic result = Db.GetCollection<dynamic>("Items").Find(x => x.Id == id).FirstOrDefaultAsync().Result;
    return result;
}

但这给了我以下错误:

CS1963表达式树可能不包含动态操作

CS1963 An expression tree may not contain a dynamic operation

我知道可以通过使用类型化对象而不是动态对象来解决此问题.但是我不想使用任何类型化的对象，因为这种方法无法达到使用像MongoDB这样的NoSQL数据库(或至少是imho)的目的.

I know this can be fixed by using a typed object instead of a dynamic one. But I don't want to use any typed objects, because that kind of defeats the entire purpose of using a NoSQL database like MongoDB (or at least, imho).

如何使用dynamic对象通过Id或任何其他属性查询我的收藏集?

How can I query my collections by Id or any other property for that matter using dynamic objects?

推荐答案

您可以使用基于字符串的语法，因为该表达式对于dynamic仍然没有任何好处:

You can use the string-based syntax, since the expression doesn't offer any advantages with dynamic anyway:

var cursor = db.GetCollection<dynamic>("foo").
                Find(Builders<dynamic>.Filter.Eq("_id", someId));

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