Using "where": Cannot convert lambda expression to type 'bool'

Question

I have entity framework code as shown below.I am getting following error in where condition.

Cannot convert lambda expression to type 'bool' because it is not a delegate type

How to overcome this error? What is the reason for this error?

    static void Main(string[] args)
    {

        ClubCreation();
        List<Club> selectedClubs = GetClubs("club1");

    }

    public static void ClubCreation()
    {

        string connectionstring = "Data Source=.;Initial Catalog=NerdDinners;Integrated Security=True;Connect Timeout=30";
        using (var db = new NerdDinners(connectionstring))
        {

            Club club1 = new Club();
            club1.ClubName = "club1";

            Club club2 = new Club();
            club2.ClubName = "club2";

            Club club3 = new Club();
            club3.ClubName = "club3";

            db.Clubs.Add(club1);
            db.Clubs.Add(club2);
            db.Clubs.Add(club3);

            int recordsAffected = db.SaveChanges();


        }
    }

    public static List<Club> GetClubs(string clubName)
    {
        string connectionstring = "Data Source=.;Initial Catalog=NerdDinners;Integrated Security=True;Connect Timeout=30";
        using (var db = new NerdDinners(connectionstring))
        {

            Club club1 = new Club();
            Club club2 = new Club();
            Club club3 = new Club();


            var query = from o in db.Clubs
                        where (p => p.ClubName == "club1")
                        select o;

            return query.ToList();





        }
    }

What is `p` supposed to be? It seems to me like a typo of `o` which you use in your LINQ query. — BoltClock, Jul 25 '12 at 07:54
And why are you hardcoding `"club1"` in your condition instead of using the `clubName` argument? — Frédéric Hamidi, Jul 25 '12 at 07:55

score 8 · Accepted Answer · answered Jul 25 '12 at 07:54

8

Instead of where (p => p.ClubName == "club1") use:

var query = from o in db.Clubs
            where  o.ClubName == "club1"
            select o;

May be you are confused with method chaining where it would be:

var query = db.Clubs.Where(p => p.ClubName == "club1");

answered Jul 25 '12 at 07:54

Habib

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Rather could it be... where o.ClubName == "club1" – Arif Eqbal Jul 25 '12 at 07:55
Thanks. Suppose I am using FirstOrDefault instead of WHERE. How do we make "var query" to a Club object? – LCJ Jul 27 '12 at 12:19
1

`var query = db.Clubs.FirstOrDefault(p => p.ClubName == "club1");` – Habib Jul 27 '12 at 15:10

Shai · Answer 2 · 2012-07-25T07:59:28.700

1

        var query = from o in db.Clubs
                    where o.ClubName == "club1"
                    select o;

edited Jul 25 '12 at 07:59

answered Jul 25 '12 at 07:54

Shai

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LOL I was just thinking that to myself :-) – Shai Jul 25 '12 at 07:58

albertjan · Answer 3 · 2012-07-25T08:20:40.543

1

The => syntax is used in the method chain notation. You probably also want to use the clubName variable instead of "club1".

var query = db.Clubs.Where (p => p.ClubName == clubName);

which does the same as this (which is the correct syntax for your query):

var query = from o in db.Clubs
            where o.ClubName == clubName
            select o;

edited Jul 25 '12 at 08:20

answered Jul 25 '12 at 07:55

albertjan

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You're right, but that (unlike the other answers) doesn't say what the correct syntax is. – Jul 25 '12 at 07:58
Absolutely right. :) That would make it answered with the same answer 3 times :P – albertjan Jul 25 '12 at 07:59

score 1 · Answer 4 · answered Jan 21 '16 at 10:46

1

In asp mvc Razor while i tried:

@if (modelItem => item.Id == 1)
 {

<span class="badge progressbar-success">Approved</span> 

 }

Cannot convert lambda expression to type 'bool' because it is not a delegate type

Solution:

@if (Model.FirstOrDefault().Id == 1)
{

<span class="badge progress-bar-success">Approved</span>

}

Hope helps someone.

answered Jan 21 '16 at 10:46

Shaiju T

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@shaijt Thank you so much It Help me a lot – Engr. Khuram Shahzad Oct 22 '20 at 13:30

Aghilas Yakoub · Answer 5 · 2012-07-25T08:00:32.073

0

var query = from o in db.Clubs
            where o.ClubName == "club1"
            select o;

edited Jul 25 '12 at 08:00

answered Jul 25 '12 at 07:55

Aghilas Yakoub

28,516
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Just FYI... indenting with four spaces is meant for code blocks only. Please don't make your entire text a code block. People have edited some of your previous posts but it looks like you haven't gotten the hint. See http://stackoverflow.com/editing-help to learn how to format your posts, and please use the edit link to fix them. – BoltClock Jul 25 '12 at 07:57

Using "where": Cannot convert lambda expression to type 'bool'

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