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    <p>If all the 'blahs' (classes) that you will be filtering have the same structure, you can use a simple method like this. The main difference is that it returns an Expression that Linq should be able to parse and it brings in the whole instance and filters on Name instead of bringing in just the string name.</p> <pre><code> public static Expression&lt;Func&lt;T, bool&gt;&gt; BuildStringMatch&lt;T&gt;(string searchFor) where T : IHasName { return b =&gt; string.IsNullOrEmpty(searchFor) || (b.Name != null &amp;&amp; (b.Name.Trim().ToLower().StartsWith(searchFor.Trim().ToLower()) || b.Name.Contains(" " + searchFor))); } </code></pre> <p>You can use that method like this:</p> <pre><code> IQueryable&lt;Blah&gt; blahs = query.Where(BuildStringMatch&lt;Blah&gt;(searchText)); </code></pre> <p>That assumes all your classes that you'd want to filter on implement some interface such as:</p> <pre><code> public interface IHasName { string Name { get; } } </code></pre> <p>If you want to be filtering on different properties, I don't think that's something you can do with simple code like this. I believe you'll need to build the Expression yourself with reflection (or with the help of a library that uses reflection) - it's still possible but much more difficult.</p> <p>Edit: It sounds like you need dynamic behavior, so I borrowed some logic from <a href="https://stackoverflow.com/users/76217/dtb">dtb</a>'s answer to <a href="https://stackoverflow.com/questions/3431617/creating-dynamic-predicates-passing-in-property-to-a-function-as-parameter/3431670#3431670">this question</a> and came up with this:</p> <pre><code>public static Expression&lt;Func&lt;T, bool&gt;&gt; BuildStringMatch&lt;T&gt;(Expression&lt;Func&lt;T, string&gt;&gt; property, string searchFor) { var searchForExpression = Expression.Constant(searchFor, typeof(string)); return Expression.Lambda&lt;Func&lt;T, bool&gt;&gt;( Expression.OrElse( Expression.Call(typeof(string), "IsNullOrEmpty", null, searchForExpression), Expression.AndAlso( Expression.NotEqual(property.Body, Expression.Constant(null, typeof(string))), Expression.OrElse( Expression.Call(Expression.Call(Expression.Call(property.Body, "Trim", null), "ToLower", null), "StartsWith", null, Expression.Call(Expression.Call(searchForExpression, "Trim", null), "ToLower", null)), Expression.Call(property.Body, "Contains", null, Expression.Call(typeof(string), "Concat", null, Expression.Constant(" "), searchForExpression)) ) ) ), property.Parameters ); } </code></pre> <p>You would use it like:</p> <pre><code> IQueryable&lt;Blah&gt; blahs2 = query.Where(BuildStringMatch&lt;Blah&gt;(b =&gt; b.Name, searchText)); </code></pre> <p>It's long and verbose but you can see how it's similiar to the original method written in straight C# code. Note: I didn't test this code, so there could be a few small problems - but that is the general idea.</p>
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    1. POHow to stay DRY whilst using LINQ to Entities and helper methods?
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    1. USStephen McDaniel
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    1. COThanks for answering, I did consider something like this, but the lack of flexibility is off-putting (not everything I want to match is called "Name"). Any hints on where to start with the more complicated way?
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    2. COI've edited my answer to include some sample code. It certainly looks more complicated but if you only have to write it once.....maybe it won't be so bad.
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    3. COThanks, that's really helpful (shame I can only upvote once). However, I've found some other code in our codebase that uses a library called LINQKit to do something very similar in (I think) a neater way. I'll add a new answer with the full details.
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