MongoDB .NET – Get IMongoCollection by Name
I’m refactoring some legacy code away from the MongoDB.Driver.Legacy API.
I’ve got the following method, which gets a MongoCollection by string collection name.
protected virtual MongoCollection GetMongoCollection(Type type) { return Store.GetCollection(GetCollectionName(type)); } Store in this example is a MongoDatabase from the Legacy API. The GetCollectionName() method looks up various things in BsonClassMap to determine the string name of the collection:
private string GetCollectionName(Type type) { return !IsRegisteredWithClassMap(type) ? type.Name : GetRegisteredClassMapType(type).Name; } private Type GetRegisteredClassMapType(Type objectType) { if (objectType.BaseType == null) { return null; } var isroot = BsonClassMap.LookupClassMap(objectType.BaseType).IsRootClass; return isroot ? objectType.BaseType : GetRegisteredClassMapType(objectType.BaseType); } private bool IsRegisteredWithClassMap(Type objectType) { var isRegistered = GetRegisteredClassMapType(objectType); return isRegistered != null; } How would I implement the GetMongoCollection() method using the new API. The IMongoDatabase from the new API doesn’t have a GetCollection() method which accepts a string. Only a Generic version GetCollection<T>
try this:
protected virtual MongoCollection GetMongoCollection(Type type) { var method = typeof(IMongoDatabase).GetMethod("GetCollection"); var result = method.MakeGenericMethod(type).Invoke(yourMongoDbInstance); return (MongoCollection) result; } if you can afford more effort just change the previous method signature in this way:
protected virtual MongoCollection GetMongoCollection<T>() { return yourMongoDbInstance.GetCollection<T>(); } 
