CODEWITHSUNDEEP
c#linqentity-frameworkpredicatebuilder
VansFannel
VansFannel

Reputation: 45961

PredicateBuilder returns all users predicate.Or

I'm developing a library with C#, Entity Framework Code First 4.4.0.0 and .NET Framework 4.0.

I have this code:

string[] keywords = null;
if (query_string != null)
    keywords = query_string.Split(' ');

// Check parameter. It will throw an exception.
ParameterCheck.CheckObjectId(user_id);

// Convert parameter to int.
int userId = Int32.Parse(user_id);

try
{
    using (var context = new AdnLineContext())
    {
        context.Configuration.ProxyCreationEnabled = false;

        //IQueryable<User> query = context.Users;
        IQueryable<User> query = context.Users.AsExpandable();
        var predicate = PredicateBuilder.False<User>();

        foreach (string keyword in keywords)
        {
            string temp = keyword;

            predicate = predicate.Or(u => u.Name.Contains(temp) ||
                                     u.State.Contains(temp) ||
                                     u.HashTags.Contains(temp));
        }
        query.Where(predicate);
        query.Include("WhoHasBlockedMe").Include("Friends");

        var users = query.ToList();

        [ ... ]
    }
}

if keywords = {"john", "happy"} I want to get this SQL:

select * from users where
users.name like '%john%' or 
users.state like '%john%' or 
users.hashtags like '%john%' or 
users.name like '%happy%' or 
users.state like '%happy%' or 
users.hashtags like '%happy%';

How can I do that with PredicateBuilder?

By the way, I have downloaded LinqKit from http://www.albahari.com/nutshell/predicatebuilder.aspx

UPDATE
I have added a breakpoint at var users = query.ToList(); and query has this SQL:

{SELECT 
[Extent1].[UserId] AS [UserId],
[...]
FROM [dbo].[Users] AS [Extent1]}

It doesn't have a Where clause.

Upvotes: 1

Views: 1104

Answers (2)

D Stanley
D Stanley

Reputation: 152624

Your problem is here:

query.Where(predicate);
query.Include("WhoHasBlockedMe").Include("Friends");

var users = query.ToList();

.Where and .Include don't modify the underlying query, they return a new query.

Use

query = query.Where(predicate);
query = query.Include("WhoHasBlockedMe").Include("Friends");

var users = query.ToList();

instead.

Upvotes: 5

Servy
Servy

Reputation: 203825

What's the result of true OR something Or SomethingElse?

Do you even need to know what something is?

It will always be true.

You need to start out with False, not True. False Or anything is equivalent to anything.

If you were AND-ing items, you'd start with true, given that true AND anything is equivalent to anything.

Upvotes: 1

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