How to check results of LINQ to SQL query?

Question

In a WPF app I'd like to check if a return of a LINQ to SQL query contains some records, but my approach doesn't work:

        TdbDataContext context = new TdbDataContext();
        var sh = from p in context.Items where p.Selected == true select p;

        if (sh == null)
        {
            MessageBox.Show("There are no Selected Items");
        }

Where am I wrong?

Sam Harwell · Accepted Answer · 2010-03-12 06:04:21Z

8

A linq query will never be null because it will always return an IQueryable. Try calling sh.Any() instead.

if (!sh.Any())
    MessageBox.Show("There are no Selected Items");

edited Mar 12, 2010 at 6:04

Sam Harwell

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answered Mar 12, 2010 at 6:00

rossisdead

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2 Comments

Sam Harwell Over a year ago

@IanR: IQueryable doesn't have a Count property. Any() is the correct answer.

kiwipom Over a year ago

@280Z28 - Sorry, my bad, I was thinking of the Count() extension method, but as someone else pointed out, this would enumerate the sequence.. +1 from me for Any(), anyway :)

hasan · Accepted Answer · 2013-03-25 09:32:33Z

1

    var query = (from k in context.invis select k.invoice);
    if (query.Count() > 0)
    {

    }
    else
    {

    }
    //

answered Mar 25, 2013 at 9:32

hasan

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