C# MongoDB 复杂 class 序列化

Question

我正在使用 C# MongoDB 驱动程序，我有这个相当复杂的 JSON 结构要保存：

{
    "name" : "value",
    "age": 1,
    "isFemale": true,
    "Hobbies" : {
        //All data within the "Hobbies" node is dynamic
        //and may change from one item to another.
        "stringItem" : "value",
        "intItem" : 0.0,
        "listOfItems" : [
            { "field" : 1696.0 }
        ],
        "intArray" : [ 566.0,  1200.0 ]
    },
    "Collection" : [ 
        //All data within the "Collection" node is dynamic
        //and may change from one item to another.
        {
            "field" : "string",
            "FieldTypeId" : 2.0,
            "array" : [ 
                { "value" : "1024x1000" }
            ]
        }
    ]
}

我有这个 class 代表上面的对象：

public class MyClass
{
    public string Name;
    public int Age;
    public bool IsFemale;
    public Dictionary<string, object> Hobbies;
    public List<Dictionary<string, object>> Collection;
}

这是我为 "Hobbies" 部分保存的内容：

"Hobbies": {
    "stringItem": "value",
    "intItem": 1,
    "listOfItems": {
        "_t": "Newtonsoft.Json.Linq.JArray, Newtonsoft.Json, Version=10.0.0.0, Culture=neutral, PublicKeyToken=30ad4fe6b2a6aeed",
        "_v": [{
            "_t": "JObject",
            "_v": [{
                "_t": "JProperty",
                "_v": [{
                    "_t": "JValue",
                    "_v": []
                }]
            },
            {
                "_t": "JProperty",
                "_v": [{
                    "_t": "JValue",
                    "_v": []
                }]
            }]
        }]
    }
}

我猜我应该为那个 class 编写一个自定义序列化程序，但我在 MONGODB .NET DRIVER Manual

中找不到任何有用的示例

我试着开始并实施这样的事情：

public class MyClassSerializer : SerializerBase<MyClass>, IBsonDocumentSerializer
{
    public override void Serialize(BsonSerializationContext context, BsonSerializationArgs args, MyClass value)
    {
        //What to do here???
        base.Serialize(context, args, value);
    }

    public override MyClass Deserialize(BsonDeserializationContext context, BsonDeserializationArgs args)
    {
        //What to do here???
        return base.Deserialize(context, args);
    }

    public bool TryGetMemberSerializationInfo(string memberName, out BsonSerializationInfo serializationInfo)
    {
        switch (memberName)
        {
            case "Name":
                serializationInfo = new BsonSerializationInfo(memberName, new StringSerializer(), typeof(string));
                return true;
            case "Age":
                serializationInfo = new BsonSerializationInfo(memberName, new Int16Serializer(), typeof(string));
                return true;
            case "IsFemale":
                serializationInfo = new BsonSerializationInfo(memberName, new BooleanSerializer(), typeof(string));
                return true;
            case "Hobbies":
                serializationInfo = new BsonSerializationInfo(memberName, new TupleSerializer<string, object>(), typeof(string));
                return true;
            case "Collection":
                serializationInfo = new BsonSerializationInfo(memberName, new ArraySerializer<Dictionary<string, object>>(), typeof(string));
                return true;
            default:
                serializationInfo = null;
                return false;
        }
    }
}

但我找不到与此相关的任何内容。它没有完全实现，我读到我需要在某个地方注册序列化程序，但是在哪里...？

Answer 1

在这里找到了如何将数据保存到 MongoDB：Dictionary-to-BsonDocument conversion omitting _t field 并对其进行了一些扩展，所以我想分享完整的解决方案。

第 1 步：

在我的 class 中，我为每个值声明了 2 个成员：

// For the Hobbies object type:
[BsonIgnore] //ignore this value in MongoDB
public Dictionary<string, object> Hobbies { get; set; }

[JsonIgnore] //ignore this value in the response on Get requests
[BsonElement(elementName: "Hobbies")]
public BsonDocument HobbiesBson { get; set; }

/*********************************************************************/

// For the Collection object type:
[BsonIgnore] //ignore this value in MongoDB
public List<Dictionary<string, object>> Collection { get; set; }

[JsonIgnore] //ignore this value in the response on Get requests
[BsonElement(elementName: "Collection")]
public BsonArray CollectionBson { get; set; }

第 2 步

在我的 Post

的 WebAPI 控制器方法中

[HttpPost]
public override async Task<IActionResult> Post([FromBody] Person person)
{
    var jsonDoc = JsonConvert.SerializeObject(person.Hobbies);
    person.HobbiesBson = BsonSerializer.Deserialize<BsonDocument>(jsonDoc);

    jsonDoc = JsonConvert.SerializeObject(person.Collection);
    person.CollectionBson = BsonSerializer.Deserialize<BsonArray>(jsonDoc);

    //save
}

步骤#3

在我的 Get 请求中，我像这样反序列化它：

[HttpGet("{id?}")]
public override async Task<IActionResult> Get(string id = null)
{
    var people = //get data from mongoDB
    foreach (var person in people)
    {
        var bsonDoc = BsonExtensionMethods.ToJson(person.HobbiesBson);
        person.Hobbies = JsonConvert.DeserializeObject<Dictionary<string, object>>(bsonDoc);

        bsonDoc = BsonExtensionMethods.ToJson(person.CollectionBson);
        person.Collection = JsonConvert.DeserializeObject<List<Dictionary<string, object>>>(bsonDoc);bsonDoc);
    }
    return Ok(people);
}

这解决了我的问题，我希望它也能帮助其他人:-)

Answer 2

一种无需创建额外属性即可处理此问题的简单方法是注册自定义序列化程序。

ComplexTypeSerializer.cs

namespace MyNamespace.MongoDB.Serializers
{
    public class ComplexTypeSerializer : SerializerBase<object>
    {
        public override object Deserialize(BsonDeserializationContext context, BsonDeserializationArgs args)
        {
            var serializer = BsonSerializer.LookupSerializer(typeof(BsonDocument));
            var document = serializer.Deserialize(context, args);

            var bsonDocument = document.ToBsonDocument();

            var result = BsonExtensionMethods.ToJson(bsonDocument);
            return JsonConvert.DeserializeObject<IDictionary<string, object>>(result);
        }

        public override void Serialize(BsonSerializationContext context, BsonSerializationArgs args, object value)
        {
            var jsonDocument = JsonConvert.SerializeObject(value);
            var bsonDocument = BsonSerializer.Deserialize<BsonDocument>(jsonDocument);

            var serializer = BsonSerializer.LookupSerializer(typeof(BsonDocument));
            serializer.Serialize(context, bsonDocument.AsBsonValue);
        }
    }
}

并按照http://mongodb.github.io/mongo-csharp-driver/2.3/reference/bson/serialization/

注册

BsonSerializer.RegisterSerializer(typeof(IDictionary<string, object>), new ComplexTypeSerializer());

或

BsonSerializer.RegisterSerializer(typeof(IList<IDictionary<string, object>>), new ComplexTypeSerializer());

下面的代码使用简单的 IDictionary<string, object> 进行了测试，不确定它是否适用于 IList<IDictionary<string, object>>，但是如果不支持，您可以创建另一个自定义序列化程序来支持它。

C# MongoDB 复杂 class 序列化

C# MongoDB complex class serialization

c#

mongodb

mongodb-.net-driver