Solved

Counting records using LINQ

Posted on 2010-11-12
4
699 Views
Last Modified: 2013-11-11
HI

I'm new to LINQ, so I'm guessing my issue is probably pretty basic;

I've created a new datacontext and have executed a query on it.

i.e;

SomeDataContext dc = new SomeDataContext(connString);

IEnumerable<Reading> readings =dc.ExecuteQuery<Reading>(SQL, thing1, thing2);

int count_readings = readings.Count();

returns the error
"The query result cannot be enumerated more than once"

I could get the number of records via:

count_readings = (from thing1 in dc.Readings select thing1).Count();
but thats not very useful!

Help much appreciated!


0
Comment
Question by:Spike_66
[X]
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
  • 2
4 Comments
 
LVL 26

Expert Comment

by:Shaun Kline
ID: 34121158
According to http://stackoverflow.com/questions/168901/howto-count-the-items-from-a-ienumerablet-without-iterating, Count() is not "truly" implemented for IEnumerable, even though it appears as a method of the object. If you need a count, the suggestion is to return your objects into either a ICollection or IList as both of them support Count(). Otherwise, you would need to iterate through your IEnumerable to find the count.
0
 
LVL 18

Accepted Solution

by:
Richard Lee earned 125 total points
ID: 34121273
Try this:

var readings =dc.ExecuteQuery<Reading>(SQL, thing1, thing2).ToArray();
int count_readings = readings.Length;

DaTribe
0
 

Author Closing Comment

by:Spike_66
ID: 34121411
Excellent and simply explained
0
 
LVL 18

Expert Comment

by:Richard Lee
ID: 34121855
Glad to help!
0

Featured Post

On Demand Webinar - Networking for the Cloud Era

This webinar discusses:
-Common barriers companies experience when moving to the cloud
-How SD-WAN changes the way we look at networks
-Best practices customers should employ moving forward with cloud migration
-What happens behind the scenes of SteelConnect’s one-click button

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

This document covers how to connect to SQL Server and browse its contents.  It is meant for those new to Visual Studio and/or working with Microsoft SQL Server.  It is not a guide to building SQL Server database connections in your code.  This is mo…
The article shows the basic steps of integrating an HTML theme template into an ASP.NET MVC project
There are cases when e.g. an IT administrator wants to have full access and view into selected mailboxes on Exchange server, directly from his own email account in Outlook or Outlook Web Access. This proves useful when for example administrator want…
NetCrunch network monitor is a highly extensive platform for network monitoring and alert generation. In this video you'll see a live demo of NetCrunch with most notable features explained in a walk-through manner. You'll also get to know the philos…

717 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question