How do I build up LINQ dynamically

views:

1098

answers:

+2 Q:

How do I build up LINQ dynamically

I have a scenario where I have custom configured column names, associated operators like < > = between etc. and then a value associated.

I'm trying to determine if it is possible to build up a LINQ query with a dynamic (string) where clause?

I've noticed the Predicate.OR Preditcate.AND stuff, but that is not quite what I'm talking about.

Any suggestions?

+4 A:

Actually, there is a specific library from Microsoft (System.Linq.Dynamic) that comes with the C# VS2008 samples that supports this. Get it from here (Microsoft Download)

The library is included in the \LinqSamples\DynamicQuery directory of the samples of above download.

For extensive usage examples check this page: http://weblogs.asp.net/scottgu/archive/2008/01/07/dynamic-linq-part-1-using-the-linq-dynamic-query-library.aspx

Alex 2009-08-18 08:18:07

Ok, System.Linq.Dynamic looks like exactly what I'm looking for at first glance.However Dynamic linq only works on IQueryable and not IEnumerable.So this still leaves a bit of a problem.

Jabezz 2009-08-18 11:55:57

+4 A:

Marc Gravell 2009-08-18 08:19:43

You SO copied me :) haha

Alex 2009-08-18 08:20:25

Although Alex was first with the Dynamic LINQ library, the part that was missing was raised by Marc (sorry for missing that). You need the .AsQueryAble() extension method to be able to work with your collections.

Jabezz 2009-08-19 10:10:49

+1 A:

Also you can use expression trees to created dynamic queries. See:

http://msdn.microsoft.com/en-us/library/bb397951.aspx

http://www.interact-sw.co.uk/iangblog/2005/09/30/expressiontrees

http://blogs.msdn.com/charlie/archive/2008/01/31/expression-tree-basics.aspx

Kamarey 2009-08-18 08:48:07

ansaurus

tags:

views:

answers:

How do I build up LINQ dynamically

related questions