pgs. 506-512 "r" ?

Rachel · January 1st, 2009, 03:22 PM

Hi Imar:

In the code on those pages, what is "r"? Is it a special character or is it a variable we create? (looking at the C# code on pages 507 & 512.

And if it is a variable, what isn't it a number rather than a letter since we're looking for a review.ID?

Rachel

Imar · January 1st, 2009, 05:51 PM

Hi Rachel,

Take a look (back) at chapter 13 - LINQ, with page 433 in particular. It shows the following LINQ query:

var allReviews = from r in myDataContext.Reviews
select r;

Right below it, r is explained and referred to as a "range variable" which is available within the context of the query. It's used to refer to an item in the collection in the relevant parts of the query (in the select clause to select it, in the where clause to filter it and so on).
So, yes, it is indeed a variable name. You can make up anything you want as long it's a valid C# variable name. That rules out pure number though.

I typically use a single letter from the strongly typed items I am querying. So, I'd use a b for Books, an r for Reviews and so on. However, if you want you can be more expressive:

var allReviews = from review in myDataContext.Reviews
select review;

Hope this helps,

Imar

Rachel · January 1st, 2009, 07:29 PM

I'm sorry.

I even had it highlighted! I thought I had read something about that, but then I couldn't find it. I didn't go back far enough in the chapters. (I wish I had a copy of this in pdf format!)

Thanks for your patience,

Rachel

Imar · January 2nd, 2009, 05:02 AM

No problem, and you're welcome.....

Imar