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PONavigation Property Filter
 

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    <p>My question is this: How can you implement a default server-side "filter" for a <a href="http://www.breezejs.com/documentation/navigation-properties" rel="nofollow noreferrer">navigation property</a>?</p> <p>In our application we seldom actually delete anything from the database. Instead, we implement "soft deletes" where each table has a <code>Deleted</code> bit column. If this column is true the record has been "deleted". If it is false, it has not. </p> <p>This allows us to easily "undelete" records accidentally deleted by the client.</p> <p>Our current ASP.NET Web API returns only "undeleted" records by default, unless a <code>deleted</code> argument is sent as <code>true</code> from the client. The idea is that the consumer of the service doesn't have to worry about specifying that they only want undeleted items. </p> <p>Implementing this same functionality in Breeze is quite simple, at least for base entities. For example, here would be the implementation of the classic Todo's example, adding a "Deleted" bit field:</p> <pre><code> // Note: Will show only undeleted items by default unless you explicitly pass deleted = true. [HttpGet] public IQueryable&lt;BreezeSampleTodoItem&gt; Todos(bool deleted = false) { return _contextProvider.Context.Todos.Where(td =&gt; td.Deleted == deleted); } </code></pre> <p>On the client, all we need to do is...</p> <pre><code>var query = breeze.EntityQuery.from("Todos"); </code></pre> <p>...to get all undeleted Todos, or... </p> <pre><code>var query = breeze.EntityQuery.from("Todos").withParameters({deleted: true}) </code></pre> <p>...to get all deleted Todos.</p> <p>But let's say that a BreezeSampleTodoItem has a child collection for the tools that are needed to complete that Todo. We'll call this "Tools". Tools also implements soft deletes. When we perform a query that uses <code>expand</code> to get a Todo with its Tools, it will return all Tools - "deleted" or not.</p> <p>But how can I filter out these records by default when <code>Todo.Tools</code> is expanded?</p> <p>It has occurred to me to have separate Web API methods for each item that may need expanded, for example:</p> <pre><code>[HttpGet] public IQueryable&lt;Todo&gt; TodoAndTools(bool deletedTodos = false, bool deletedTools = false) { return // ...Code to get filtered Todos with filtered Tools } </code></pre> <p>I found some example code of how to do this in <a href="https://stackoverflow.com/questions/11228463/load-navigation-properties-with-filter-for-entity-framework-4-3">another SO post</a>, but it requires hand-coding each property of Todo. The code from the above-mentioned post also returns a <code>List</code>, not an <code>IQueryable</code>. Furthermore this requires methods to be added for every possible expansion which isn't cool.</p> <p>Essentially what I'm looking for is some way to define a piece of code that gets called whenever <code>Todos</code> is queried, and another for whenever <code>Tools</code> is queried - preferably being able to pass an argument that defines if it should return Deleted items. This could be anywhere on the server-side stack - be it in the Web API method, itself, or maybe part of Entity Framework (note that filtering Include extensions is <a href="http://data.uservoice.com/forums/72025-entity-framework-feature-suggestions/suggestions/1015345-allow-filtering-for-include-extension-method" rel="nofollow noreferrer">not supported in EF</a>.)</p>
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