title: Pre defined expressions in LINQ query sytax
body: <p>Is it possible to use a previously defined <a href="http://msdn.microsoft.com/en-us/library/bb335710.aspx" rel="nofollow">expression</a> in LINQ expressions with <a href="http://msdn.microsoft.com/en-us/library/vstudio/bb397947.aspx" rel="nofollow">query syntax</a>?  I've created a contrived example to illustrate my question.</p>
  
  <pre><code>var tabletTypes = new List&lt;int&gt; { 2, 3 };
  //I want to use this expression many times
  Expression&lt;Func&lt;Computer, bool&gt;&gt; isTablet = comp =&gt; tabletTypes.Contains(comp.Type);
  
  var computers = db.Computers;
  var producers = db.Producers;
  
  //I know how to use the expression in fluent syntax
  IQueryable&lt;Producer&gt; tabletProducers = computers
                                 .Where(isTablet)
                                 .Join(producers, 
                                       comp =&gt; comp.ProducerId, 
                                       producer =&gt; producer.Id, 
                                       (comp, producer) =&gt; producer);
  
  //How can I use the expression in query syntax
  IQueryable&lt;Producer&gt; tabletProducers2 = from c in computers
                                          join p in producers
                                              on c.ProducerId equals p.Id
                                          where /*How can I use isTablet here?*/
                                          select p;
  
  
  public class Producer
  {
      public int Id { get; set; }
      public string Name { get; set; }
  }
  
  public class Computer
  {
      public int Id { get;set; }
      public int Type { get; set; }
      public int ProducerId { get; set; }
  }
  </code></pre>
  
  <p>I am using C# 5 and EF 5.</p>