views:

83

answers:

2

To get a page from a database I have to execute something like this:

var cs = ( from x in base.EntityDataContext.Corporates
   select x ).Skip( 10 ).Take( 10 );

This will skip the first 10 rows and will select the next 10.

How can I know how many rows would result because of the query without pagination? I do not want to run another query to get the count.

+4  A: 

To get the total number of records before skip/take you have to run a separate query. Getting the actual number returned would use Count(), but wouldn't result in another query if the original query was materialized.

var q = from x in base.EntityDataContext.Corporates 
        select x;

var total = q.Count();
var cs = q.Skip(10).Take(10);
var actual = cs.Count();
tvanfosson
+2  A: 

Bottom line: you have to run two queries. You simply can't get around it.

Here's a good way to do it, however, that caches the original LINQ query and filter, making for less copy/paste errors:

var qry = from x in base.EntityDataContext.Coporates select x;
var count = qry.Count();
var items = qry.Skip(10).Take(10).ToList();
Randolpho
I just thought about doing so - but a question; will calling the q.Count(); load all records in memory?
effkay
No, q.Count() will generate an SQL `SELECT COUNT(*)` query.
Martinho Fernandes
No. Calling q.Count() will result in SQL along the lines of `SELECT count(*) where ...`, which will only return an integer value. No records will be loaded into memory.
Randolpho