使用 mongoDB 自动生成的 id

Question

I am developing a desktop application using windows forms c#, I've created an unique index named Id in my database.

But now I want it when I send a class with field 'Id' empty so the database gives it a unique value by its own.

I am sorry for not illustrating well and also the problem may seem easy, but I don't know how because i am still a beginner

Thanks in advance.

Answer 1

No need to create a unique index yourself. MongoDB creates a unique index on the _id field during the creation of a collection.

If an inserted document omits the _id field, the MongoDB driver automatically generates an ObjectId for the _id field. ObjectId essentially a timestamp plus random value.

In your models, you can map to _id field using attributes

[BsonId]
[BsonRepresentation(BsonType.ObjectId)]
public string Id { get; set; }