C#向MongoDB集合插入文档时出错，请求技术支持

我从API请求数据，返回的是JSON对象数组，但执行collection.InsertMany(countryList);时触发错误。以下是相关代码、模型和返回数据：

主程序代码 #

static async Task CountriesAsync()
{
    var apiURL = "https://restcountries.com/v3.1/alpha/tto";

    var results = await client.GetStringAsync(apiURL);

    string connectionString = "mongodb://localhost";
    string databaseName = "world";
    string collectionName = "countries";
    MongoClient dbClient = new MongoClient(connectionString);
    var database = dbClient.GetDatabase(databaseName);
    var collection = database.GetCollection<CountryModel>(collectionName);

    BsonArray countryList = MongoDB.Bson.Serialization.BsonSerializer.Deserialize<BsonArray>(results);
    collection.InsertMany(countryList);  // 此处引发错误
}

模型代码片段 #

namespace CountryMongoDemo.Models
{
    public class CountryModel
    {
        public Name? name { get; set;}
    }

    public class Name
    {
        public string? common { get; set; }
        public string? official { get; set; }
        public NativeName? nativeName { get; set; }
    }

    public class NativeName
    {
        public Eng? eng { get; set; }
    }

    public class Eng
    {
        public string? official { get; set; }
        public string? common { get; set; }
    }
}

API返回的JSON数据片段 #

[{ "name" : { "common" : "Trinidad and Tobago", "official" : "Republic of Trinidad and Tobago", "nativeName" : { "eng" : { "official" : "Republic of Trinidad and Tobago", "common" : "Trinidad and Tobago" } } }, "tld" : [".tt"], "cca2" : "TT", "ccn3" : "780", "cca3" : "TTO", "cioc" : "TTO", "independent" : true, "status" : "officially-assigned", "unMember" : true, "altSpellings" : ["TT", "Republic of Trinidad and Tobago"], "region" : "Americas", "subregion" : "Caribbean", , "population" : 1399491, "gini" : { "1992" : 40.299999999999997 }, "fifa" : "TRI", "car" : { "signs" : ["TT"], "side" : "left" }, "timezones" : ["UTC-04:00"], "continents" : ["North America"], "flags" : { "png" : "https://flagcdn.com/w320/tt.png", "svg" : "https://flagcdn.com/tt.svg" }, "coatOfArms" : { "png" : "https://mainfacts.com/media/images/coats_of_arms/tt.png", "svg" : "https://mainfacts.com/media/images/coats_of_arms/tt.svg" }, "startOfWeek" : "monday", "capitalInfo" : { "latlng" : [10.65, -61.520000000000003] } }]

错误原因及修复方案 #

1. 核心问题：类型不匹配 #

你定义的集合是GetCollection<CountryModel>，但InsertMany方法期望接收IEnumerable<CountryModel>类型的参数，而你传入的是BsonArray，两者类型不兼容，直接导致报错。

2. 修复方法 #

方法一：直接反序列化为List<CountryModel>

把API返回的JSON字符串直接反序列化为CountryModel的列表，这样可以直接传入InsertMany：

// 替换原反序列化和插入代码
List<CountryModel> countryList = MongoDB.Bson.Serialization.BsonSerializer.Deserialize<List<CountryModel>>(results);
collection.InsertMany(countryList);

也可以用Newtonsoft.Json进行反序列化：

List<CountryModel> countryList = Newtonsoft.Json.JsonConvert.DeserializeObject<List<CountryModel>>(results);
collection.InsertMany(countryList);

方法二：将BsonArray转换为CountryModel集合

如果必须保留BsonArray的处理逻辑，可以手动转换类型：

BsonArray countryList = MongoDB.Bson.Serialization.BsonSerializer.Deserialize<BsonArray>(results);
var countryModels = countryList.Select(bsonDoc => bsonDoc.AsBsonDocument.To<CountryModel>()).ToList();
collection.InsertMany(countryModels);

3. 额外注意事项 #

• 你提供的JSON片段存在格式错误："subregion" : "Caribbean", ,有多余的逗号，这会导致反序列化失败，建议确认实际API返回的JSON格式是否正确，若有此类问题需先修正。
• 当前CountryModel仅定义了name相关字段，API返回的其他字段（如tld、population等）会被忽略，如果需要保存这些字段，需在模型中补充对应的属性。

内容的提问来源于stack exchange，提问作者ChrisJ