问题
Im working on a project that use .NET Razor and mongodb. I would like to do something like this:
@{
var feeds = DP.Database.GetCollection("feeds").FindAll();
}
<ul>
@foreach (dynamic feed in feeds)
{
<li>@feed.message - @feed.from.name</li>
}
</ul>
However, the current mongodb C# driver FindAll() return collection of BsonDocument which does not support dynamic object. Anybody know a .NET 4 dynamic supported mongodb C# driver?
Thanks a lot
回答1:
Currently, there is no support for dynamic in the MongoDB driver. This is because it is based on .NET 3.5. However, since a .NET 4.0 assembly can reference a .NET 3.5 assembly, it is possible for you to write a IBsonSerializationProvider and an IBsonSerializer in .NET 4.0 to support dynamics.
We, 10gen, are looking at doing this in the future. I have spiked some support at https://github.com/craiggwilson/mongo-csharp-driver/tree/dynamic if you want to take a look. There are most definitely bugs, but it shows that it is possible.
回答2:
I created a straight-forward extension to the MongoDB driver that re-serializes the BSON document using Json.NET and deserializes it as a dynamic. By including the following class, you can simply convert your MongoDB queries to dynamic like this
dynamic obj = collection.FindOneByIdAs<BsonDocument>(someObjectId).ToDynamic();
Extension class:
public static class MongoDynamic
{
private static System.Text.RegularExpressions.Regex objectIdReplace = new System.Text.RegularExpressions.Regex(@"ObjectId\((.[a-f0-9]{24}.)\)", System.Text.RegularExpressions.RegexOptions.Compiled);
/// <summary>
/// deserializes this bson doc to a .net dynamic object
/// </summary>
/// <param name="bson">bson doc to convert to dynamic</param>
public static dynamic ToDynamic(this BsonDocument bson)
{
var json = objectIdReplace.Replace(bson.ToJson(), (s) => s.Groups[1].Value);
return Newtonsoft.Json.JsonConvert.DeserializeObject<dynamic>(json);
}
}
Be sure to reference Newtonsoft.Json.dll (http://james.newtonking.com/projects/json-net.aspx)
回答3:
I have a clean solution using custom IBsonSerializer and Newtonsoft.Json.
Setup your custom serializer on the BsonClassMap
map.MapProperty(member => member.Data)
.SetElementName("Data")
.SetSerializer(new DynamicSerializer());
or on the property
[BsonSerializer(typeof(DynamicSerializer))]
public dynamic Data { get; set; }
And just include the following class
public class DynamicSerializer : IBsonSerializer
{
#region Implementation of IBsonSerializer
public object Deserialize(BsonReader bsonReader, Type nominalType, IBsonSerializationOptions options)
{
return Deserialize(bsonReader, nominalType, null, options);
}
public object Deserialize(BsonReader bsonReader, Type nominalType, Type actualType,
IBsonSerializationOptions options)
{
if (bsonReader.GetCurrentBsonType() != BsonType.Document) throw new Exception("Not document");
var bsonDocument = BsonSerializer.Deserialize(bsonReader, typeof(BsonDocument), options) as BsonDocument;
return JsonConvert.DeserializeObject<dynamic>(bsonDocument.ToJson());
}
public IBsonSerializationOptions GetDefaultSerializationOptions()
{
return new DocumentSerializationOptions();
}
public void Serialize(BsonWriter bsonWriter, Type nominalType, object value, IBsonSerializationOptions options)
{
var json = (value == null) ? "{}": JsonConvert.SerializeObject(value);
BsonDocument document = BsonDocument.Parse(json);
BsonSerializer.Serialize(bsonWriter, typeof(BsonDocument), document,options);
}
#endregion
}
InfoSlips - GlobalKinetic
回答4:
Just to build on Maximilian's answer. This will return a list of dynamics from any query.
/// <summary>
/// deserializes this BsonDocument cursor result to a list of .net dynamic objects
/// </summary>
/// <param name="cursor">cursor result to convert to dynamic</param>
/// <returns></returns>
public static List<dynamic> ToDynamicList(this MongoCursor<BsonDocument> cursor)
{
var dynamicList = new List<dynamic>();
var list = cursor.ToList();
for (int i = 0, l = list.Count; i < l; i++)
dynamicList.Add(list[i].ToDynamic());
return dynamicList;
}
回答5:
Even though this is an old topic its still just as relevant today as when post was made, and I have yet to see any solutions out there that provides a simple solution for two way support, I have modified @Maximilian Scherer code so that it lets you convert to dynamic objects which easily let you save your Document again.
public static class MongoDynamic
{
/// <summary>
/// deserializes this bson doc to a .net dynamic object
/// </summary>
/// <param name="bson">bson doc to convert to dynamic</param>
public static dynamic ToDynamic(this BsonDocument bson)
{
var json = bson.ToJson(new MongoDB.Bson.IO.JsonWriterSettings { OutputMode = JsonOutputMode.Strict });
dynamic e = Newtonsoft.Json.JsonConvert.DeserializeObject<ExpandoObject>(json);
BsonValue id;
if (bson.TryGetValue("_id", out id))
{
// Lets set _id again so that its possible to save document.
e._id = new ObjectId(id.ToString());
}
return e;
}
}
Example of usage:
// Get BsonDocument from db here
BsonDocument doc = ...
// Convert to dynamic.
var d = doc.ToDynamic();
// Lets add a none existant property.
d.Name = "test";
// Assuming you already have your collection set up
collection.Save(new BsonDocument(d));
来源:https://stackoverflow.com/questions/10222472/is-there-mongodb-c-sharp-driver-support-system-dynamic-dynamicobject-in-net-4