CODEWITHSUNDEEP
vb.netlinq
Riddari
Riddari

Reputation: 1773

How do I iterate through a string.Split() array, joining LINQ query results for each item together?

In my application, I have a search query textbox (txtSearch) that works well with one-word queries with the following LINQ:

slstFilteredItems = From s In slstItems _
                    Where s.strText.IndexOf(txtSearch.Text, StringComparison.OrdinalIgnoreCase) >= 0 _
                    Select s

But if you search this with a multiple-word query, say "Create customer" (no quotes), it only finds results that contain the result "Create Customer" exactly (case-insensitive).

So the simplest way to handle this that I can think of is with a query that does a .Intersect with each word in sequence, like this:

slstFilteredItems = (From s In slstItems _
                    Where s.strText.IndexOf(txtSearch.Text.Split(" ")(0), StringComparison.OrdinalIgnoreCase) >= 0 _
                    Select s).Intersect _
                    (From s In slstItems _
                    Where s.strText.IndexOf(txtSearch.Text.Split(" ")(1), StringComparison.OrdinalIgnoreCase) >= 0 _
                    Select s)
                    'And so on...

So how would I make the above query more generic (ie: able to handle any number of words in a query)?

I should note that the object being queried is a List of strings pulled from an Access database. As it stands, this application only queries the database once and I'd like to keep it that way if possible.

Upvotes: 0

Views: 2005

Answers (3)

msarchet
msarchet

Reputation: 15242

This should work for an arbitrary number of items in the txtSearch.text.Split array

slstFilteredItems = (From splits In txtSearch.Text.Split(" ").ToList _
                    From s In slstItems _
                    Where s.strText.IndexOf(splits, StringComparison.OrdinalIgnoreCase) >= 0 _
                    Select s)

Upvotes: 1

diceguyd30
diceguyd30

Reputation: 2752

Here is one possible approach:

Dim words = "Dog cAt biRD"
Dim slstItems = New String() { "dog thing cat bird ", "bird cat", "cat foo dog bird " }

'Query Syntax (with some fluent syntax)
Dim q = From s In slstItems.Select(Function(x) x.ToLower())
        Where words.Split(" ").Select(Function(x) x.ToLower()).All(Function(x) s.Contains(x))
        Select s

'All Fluent Syntax 
slstItems.Select(Function(x) x.ToLower()) _
    .Where(Function(s) words.Split(" ").Select(Function(x) x.ToLower()) _
                        .All(Function(w) s.Contains(w)) _
    )

Both return:

dog thing cat bird   
cat foo dog bird

Note that this is inefficient when compared to bigtlb's answer (which is a much better solution for database searching).

Upvotes: 1

bigtlb
bigtlb

Reputation: 1572

If you are hitting a SQL Server Database, Full Text Searching may be a better approach.

http://msdn.microsoft.com/en-us/library/ms142571.aspx

Upvotes: 0

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