Update all properties of object in MongoDb

You can do that with ReplaceOneAsync instead of UpdateOneAsync.

You need a filter to match the existing document (a filter with the document id is the simplest) and the new object.

Hamster hamster = ...var replaceOneResult = await collection.ReplaceOneAsync(    doc => doc.Id == hamster.Id,     hamster);

var update = new BsonDocument("$set", new BsonDocument(entityType.GetProperties().Where(p => p.Name != "Id").Select(p => new KeyValuePair<string, object>(p.Name, entityType.GetProperty(p.Name).GetValue(task, null)))));var options = new UpdateOptions();collection.UpdateOne<MyTask>(item => item.Name == "cheque", update, options);

this code uses reflection to include all properties of the given object
to the update statement, no need to manually add all properties, as u see the Id is explicitly excluded from the update statement to avoid exception.

If you want to update your whole BsonDocument, there is an implicit conversion from BsonDocument to UpdateDefinition.

https://github.com/mongodb/mongo-csharp-driver/blob/master/src/MongoDB.Driver/UpdateDefinition.cs

var doc = new BsonDocument() { .... }UpdateDefinition<BsonDocument> update = doc;