使用C#在mongoDB中存储具有多态值的字典

Question

让我们说我们有一个关键值,它们的意义上是多态的.考虑下一个示例项目:

public class ToBeSerialized
{
    [BsonId]
    public ObjectId MongoId;
    public IDictionary<string, BaseType> Dictionary;
}

public abstract class BaseType
{
}

public class Type1 : BaseType
{
    public string Value1;
}

public class Type2:BaseType
{
    public string Value1;
    public string Value2;
}


internal class Program
{
    public static void Main()
    {
        var objectToSave = new ToBeSerialized
                               {
                                   MongoId = ObjectId.GenerateNewId(),
                                   Dictionary = new Dictionary<string, BaseType>
                                                    {
                                                        {"OdEd1", new Type1 {Value1="value1"}},
                                                        {
                                                            "OdEd2",
                                                            new Type1 {Value1="value1"}
                                                            }
                                                    }
                               };
        string connectionString = "mongodb://localhost/Serialization";
        var mgsb = new MongoUrlBuilder(connectionString);
        var MongoServer = MongoDB.Driver.MongoServer.Create(mgsb.ToMongoUrl());
        var MongoDatabase = MongoServer.GetDatabase(mgsb.DatabaseName);
        MongoCollection<ToBeSerialized> mongoCollection = MongoDatabase.GetCollection<ToBeSerialized>("Dictionary");
        mongoCollection.Save(objectToSave);

        ToBeSerialized received = mongoCollection.FindOne();
    }
}

有时当我尝试反序列化它时,我会得到反序列化错误,例如"Unknown discriminator value'具体类型的名称'".我究竟做错了什么？如果每个值存储_t为什么它不能正确映射？

Answer 1

驱动程序应该知道所有鉴别器以反序列化任何类而不会出错.有两种方法可以做到:

1.在应用启动期间全局注册:

BsonClassMap.RegisterClassMap<Type1>();
BsonClassMap.RegisterClassMap<Type2>();

2.Or虽然BsonKnownTypes attibute:

[BsonKnownTypes(typeof(Type1), typeof(Type2)]
 public class BaseType
 {

 }

如果您将使用#1或#2,则反序列化将正常工作.