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PORepository Methods vs. Extending IQueryable
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copied!<p>I have repositories (e.g. ContactRepository, UserRepository and so forth) which encapsulate data access to the domain model. </p> <p>When I was looking at <em>searching for data</em>, e.g. </p> <ul> <li>finding a contact whose first name starts with XYZ</li> <li><p>a contact whose birthday is after 1960</p> <p>(etc),</p></li> </ul> <p>I started implementing repository methods such as <strong>FirstNameStartsWith(string prefix)</strong> and <strong>YoungerThanBirthYear(int year)</strong>, basically following the many examples out there.</p> <p>Then I hit a problem - what if I have to combine multiple searches? Each of my repository search methods, such as above, only return a finite set of actual domain objects. In search for a better way, I started writing <strong>extension methods</strong> on IQueryable<T>, e.g. this:</p> <pre><code>public static IQueryable<Contact> FirstNameStartsWith( this IQueryable<Contact> contacts, String prefix) { return contacts.Where( contact => contact.FirstName.StartsWith(prefix)); } </code></pre> <p>Now I can do things such as</p> <pre><code>ContactRepository.GetAll().FirstNameStartsWith("tex").YoungerThanBirthYear(1960); </code></pre> <p>However, I found myself writing extension methods (and inventing crazy classes such as <strong>ContactsQueryableExtensions</strong> all over, and I lose the "nice grouping" by having everything in the appropriate repository.</p> <p>Is this really the way to do it, or is there a better way to achieve the same goal? </p>

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