LINQ extensions - Simplified keyword search

Recently, I came across interesting question at LINQ Forums (Dynamic conditions: How to achieve multiple "OR" conditions with LINQ? [1]). The question is whether LINQ (and especially LINQ to SQL) provides any simple way to return only records that contain one or more of specified keywords in the name. The question looks simple, but it is simple only if you know the number of keywords that you want to look for. In this case you can write following LINQ query:

  // Products that contain "kwd1" or "kwd2" in the name 
var q = from p in db.Products where p.ProductName.Contains("kwd1") || p.ProductName.Contains("kwd2") select p;

The problem with previous code is that you can't use it if the list of keywords is dynamically entered by user (and so its length may vary). Of course, if you want to run query on in-memory data, you can get very nice results by writing extension method called ContainsAny that performs test for keyword array, but if you want to be able to translate query to SQL, the situation is a bit complicated.

Published: Friday, 28 July 2006, 3:57 AM
Tags: c#
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