ASP.NET MVC: Is UpdateModel an "expensive" operation (due to Reflection)?

Question

I wondered whether UpdateModel is considered an "expensive" operation (due to Reflection lookup of the model properties), especially when seen in the context of a larger web application (think StackOverflow)?

I don't want to engage in premature optimization but I consider it a design choice to use UpdateModel which is why I'd like to know early whether it is advisable or not to go with it. The other (tedious) choice is writing my own UpdateModel method for various domain objects with fixed properties.

Thank you!

Fiertz

Answer 1

You are smart to want to not engage in premature optimization. Especially since this "optimization" would favor the processor's time over yours, which is far more expensive.

The primary rule of optimization is to optimize the slow stuff first. So consider how often you actually update a model versus selecting from your database backend. I'm guessing it's 1/10 as often or less. Now consider the cost of selecting from the database backend versus the cost of reflection. The cost of reflection is measured in milliseconds. The cost of selecting from the database backend can be measured in seconds at worst. My experience is that POSTs are rarely very slow, and when they are it's usually the database at fault rather than the reflection. I think you're likely to spend most of your optimization time on GETs.

Spires

Answer 2

Compared to network latency, database calls and general IO, the UpdateModel() call is trivial and I wouldn't bother with it.

Titleholder

Answer 3

I think UpdateModel is a bit of a shortcut that causes a huge amount of coupling between the view and the model.

I choose not to use "built-in" models (like being able to pass LINQ created objects to the view directly from the database) because I want the option to replace my model with something more sophisticated - or even just another database provider. It is very tempting to use LINQtoSQL (or ADO.NET Entities) for fast prototyping though.

What I tend to do is create my MVC application, then expose a 'service' layer which is then connected to a 'model' (which is an OO view of my domain). That way I can easily create a web service layer, swap databases, write new workflows etc without concern.

(and make sure you write your tests and use DI - it saves a lot of hassle!)

Rob

Sitter

I think the point of his question remains the same, though, whether you update domain objects directly or use a specialized edit model (which I, too, recommend). – Spires