很多时候我们都需要对实体对象进行序列化与反序列化,而ObjectId类型,只能用mongo的驱动以bson格式来序列化,但我们对外的交互,一般是json格式.
有两种解决方案:
1.自己写一个json.net的ObjectIdConverter来针对ObjectId,适用于json.net
2.增加string类型的中间变量IdStr ,优点是适用于所有情况,比如mvc自带的序列化工具等
测试代码如下:
[TestClass]
public class MongoTest
{
[TestMethod()]
public void Temp1()
{
var entity = new MyEntity()
{
Id = new ObjectId("555afe4204cbee061cc31b6f"),
Name = "ZhangSan"
};
var str = JsonConvert.SerializeObject(entity);//{"Id":"555afe4204cbee061cc31b6f","Name":"ZhangSan"}
var entity1 = JsonConvert.DeserializeObject<MyEntity>(str);
} [TestMethod()]
public void Temp2()
{
var entity = new MyEntity2()
{
Id = new ObjectId("555afe4204cbee061cc31b6f"),
Name = "ZhangSan"
};
var str = JsonConvert.SerializeObject(entity); //{"IdStr":"555afe4204cbee061cc31b6f","Name":"ZhangSan"}
var entity2 = str.FromJson<MyEntity2>();
} [TestMethod()]
public void Temp3()
{
var entity = new MyEntity3()
{
Id = new ObjectId("555afe4204cbee061cc31b6f"),
Name = "ZhangSan"
};
var str = JsonConvert.SerializeObject(entity); //{"Id":"555afe4204cbee061cc31b6f","Name":"ZhangSan"}
var entity2 = str.FromJson<MyEntity3>();
}
} public class MyEntity
{
public virtual ObjectId Id { get; set; }
public virtual string Name { get; set; }
} public class MyEntity2 : MyEntity
{
[JsonIgnore]
public override ObjectId Id { get; set; } [BsonIgnore]
public string IdStr
{
get
{
return Id.ToString();
}
set
{
ObjectId id;
ObjectId.TryParse(value, out id);
Id = id;
}
}
} public class MyEntity3 : MyEntity
{
[JsonConverter(typeof(ObjectIdConverter))]
public override ObjectId Id { get; set; }
}
public class ObjectIdConverter : JsonConverter
{
public override bool CanConvert(Type objectType)
{
return objectType == typeof(ObjectId);
} public override object ReadJson(JsonReader reader, Type objectType, object existingValue, JsonSerializer serializer)
{
if (reader.TokenType != JsonToken.String)
{
throw new Exception(
String.Format("Unexpected token parsing ObjectId. Expected String, got {0}.",
reader.TokenType));
} var value = (string)reader.Value;
return String.IsNullOrEmpty(value) ? ObjectId.Empty : new ObjectId(value);
} public override void WriteJson(JsonWriter writer, object value, JsonSerializer serializer)
{
if (value is ObjectId)
{
var objectId = (ObjectId)value; writer.WriteValue(objectId != ObjectId.Empty ? objectId.ToString() : String.Empty);
}
else
{
throw new Exception("Expected ObjectId value.");
}
}
}
