What does "new BsonValue[]{x,y,z} do?

Question

This code is used with the C# driver to select items from a document of items that have a location field value in the range of location id values, I am just providing it as an example:

 var locations = new BsonValue[] { 1, 2, 3, 4 };
 var data = collection
            .Find(Builders<BsonDocument>.Filter.In("LocationId", locations))
            .Project(x => Mapper.Map<BsonDocument, ItemViewModel>(x))
            .ToListAsync().Result;

Does BsonValue just serve to initialize an array here? Where do I get more information? How do I convert a regular C# list/array into that bson value?

Answer 1

BsonDocument provides flexible way to represent JSON/BSON in C#. Creating BsonDocument is similar to creating JSON objects.

Simple document
new BsonDocument("name", "Joe") creates JSON { "name" : "Joe" }

More complex document

new BsonDocument
{
    {"Name", "Joe"},
    {
        "Books", new BsonArray(new[]
        {
            new BsonDocument("Name", "Book1"),
            new BsonDocument("Name", "Book2")
        })
    }
}

creates JSON {"Name":"Joe", "Books" : [ { "Name":"Book1" },{ "Name":"Book2" } ]}

Array
new BsonArray(new [] {1, 2, 3}) creates JSON [1,2,3]

Convert C# class to BsonDocument
var product = new Product{ Name = "Book", Pages = 3}.ToBsonDocument() creates JSON {"Name":"Book","Pages":3}

Implicit conversion helps initialize variables
BsonValue bsonInt = 1;
BsonValue bsonBool = true;
new BsonValue[] { 1, 2, 3, 4 }