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POHow do you transfer the execution of a Expression created by an IQueryable object to a IEnumerable?
 

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  1. POHow do you transfer the execution of a Expression created by an IQueryable object to a IEnumerable?
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    <p>In my code I'd like to make my repositories IQueryable. This way, the criteria for selection will be a linq expression tree.</p> <p>Now if I want to mock my repository in theorie this is very easy : just implement the interface of my repository (which is also a IQueryable object).</p> <p>My mock repository implementation would be only a in memory collection, but my question is : Do you know an easy way to implement the IQueryable interface of my mock, to transfer the query to my in-memory collection (IEnumerable) ?</p> <p>Thanks for your response,</p> <p><strong><em>Some precision</em></strong></p> <p>The client object of my repository will use my repository this way :</p> <p>var result = from entry in MyRepository where entry.Product == "SomeProduct" select entry;</p> <p>What does ToList or AsEnumerable is to execute the query and return the result as a List or as a IEnumerable. But I have to implement the IQueryable interface on my repository, with a IQueryProvider which transform the expression in a call to a IEnumerable object.</p> <p><strong><em>Solution</em></strong></p> <p>The implementation of the solution is delegating call to IQueryable to my inmemory collection with AsQueryable.</p> <pre><code>public class MockRepository : IQueryable&lt;DomainObject&gt; { private List&lt;DomainObject&gt; inMemoryList = new List&lt;DomainObject&gt;(); #region IEnumerable&lt;DomainObject&gt; Members public IEnumerator&lt;DomainObject&gt; GetEnumerator() { return inMemoryList.GetEnumerator(); } #endregion #region IEnumerable Members IEnumerator IEnumerable.GetEnumerator() { return inMemoryList.GetEnumerator(); } #endregion #region IQueryable Members public Type ElementType { get { return inMemoryList.AsQueryable().ElementType; } } public Expression Expression { get { return inMemoryList.AsQueryable().Expression; } } public IQueryProvider Provider { get { return inMemoryList.AsQueryable().Provider; } } #endregion } </code></pre>
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