C# Selections with SQL Syntax (Not LINQ!)

posted by AdrianAisemberg(2004) 3 months, 4 days ago 0

You are right. LINQ queries are lazy and perform better, but the queries are compiled and cannot be defined by a user during runtime (unless you parse the user's expression into a dynamic LINQ expression).

The collection is already in memory. It doesn't matter how do you run a query over it. Even if you run a lazy LINQ query on a collection - the collection is already there, the query itself is executed in a lazy way.

However, creating a DataTable and loading the data into it is an expensive operation. If you already have a way to parse user-defined expressions - I wouldn't recommend using the DataTable approach. I don't know of any way to parse such expression so I use DataTables in my projects (assuming the data is small).
You can take a look at my CLAP project: http://adrianaisemberg.github.com/CLAP/.
I use such a mechanism to parse user-defined validation expressions (here: http://adrianaisemberg.github.com/CLAP/#validation_expression).

The post is about a clever use of an old existing feature. It doesn't talk about the performance of it neither recommends it over LINQ.

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