C＃Mongodb CRUD运算符更新方法

Question

I am new to c# and mongodb and having trouble resolving my update method for my api. I am following this tutorial here . I am trying to fix the deprecation on it as I go, I am currently stuck on this portion

  public void Update(ObjectId id,Product p)
    {
        p.Id = id;
        var res = Query<Product>.EQ(pd => pd.Id,id);
        var operation = Update<Product>.Replace(p);
        _db.GetCollection<Product>("Products").Update(res,operation);
    }

I have updated it in my code to look like this.

 public void Update(ObjectId id, Product p)
    {
        p.ProductId = id;
        var res = Builders<Product>.Filter.Eq(pd => pd.ProductId, id);
        var operation = Builders<Product>.Update(p);
        _db.GetCollection<Product>("Product").UpdateOne(res, operation);
    }

My problem is on the .update I cant us it as a method... so what is the correct way to construct this update method? thanks in advance for any and all help.

Answer 1

You are using the Builders incorrectly

Builders<Product>.Update

Is not a method, it exposes a number of update operations you can use, ie Set, AddToSet etc

Depending what you are trying to achieve, you would use it as follows, if you want to update individual fields you can use this:

var operation = Builders<Product>.Update.Set(u => u.SomeField, "SomeValue");

And you can chain them together, ie

var operation = Builders<Product>
    .Update
        .Set(u => u.SomeField, "SomeValue")
        .Set(u => u.SomeOtherField, "SomeOtherValue");

So using your code (which looks like you are filtering for a particular product Id, and then updating that very same field)

public void Update(ObjectId id, Product p)
{
    var res = Builders<Product>.Filter.Eq(pd => pd.ProductId, id);
    var operation = Builders<Product>.Update.Set(u => u.ProductId, id);
    _db.GetCollection<Product>("Product").UpdateOne(res, operation);
}

Where as if you wanted to replace a document entirely, you might use ReplaceOne() instead of Update