How to perform case-sensitive query with LINQ?

Ivica Basic

16y15.9kLINQ

I'm using C# in VisualStudio 2008 for database Windows application. I've got connection "db" to local database. Database contained table "tblBib" with string-type column "Redak". I want to query this table and get out all rows in which column "Redak" contains substring "Adams", but I don't want rows with substring "adams" or "aDams". I want case sensitive search.

I've tried this:

var linqUpit =

from redovi in db.tblBib

where redovi.Redak.Contains("Adams")

select redovi;

but this code gives back "Adams" and "adams" and "aDams".

What's missing?

Thanks.

3 Replies

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John Wiese16y ago
Ah, I forgot to include a link to more details as there is a little more work to get LINQ to allow enums to be passed into expressions. This link should give you the details you need, but I warn you it is not a trivial undertaking:
http://www.aaronlerch.com/blog/2008/12/15/case-insensitive-string-comparisons-with-linq-dynamic-query/

Another approach )and possibly easier) is to create your own EqualityComparer as noted in this documentation on MSDN for .Contains:
http://msdn.microsoft.com/en-us/library/bb339118.aspx
Ivica Basic16y ago
Thank you.
If I try something like this I've got the error message from Visual Studio IntelliSense:

Error 1 The type arguments for method 'System.Linq.Enumerable.Contains(System.Collections.Generic.IEnumerable, TSource, System.Collections.Generic.IEqualityComparer)' cannot be inferred from the usage. Try specifying the type arguments explicitly.

I don't know what does it means.

Ivica
John Wiese16y ago
You could try passing a StringComparison value in your where clause like this:

where redovi.Redak.Contains("Adams", System.StringComparison.CurrentCulture)

The problem could by on the database side though since the LINQ expression will be turned into an appropriate SQL Syntax and thus your DB will have to support case insensitive queries