title: Build lambda expression (predicate) with dynamic comparison operators
body: <p>Take Northwind as example.  </p>
  
  <p>My goal is to use Linq to Entity to search Employees dynamically.  </p>
  
  <p>My expression maybe:  </p>
  
  <pre><code>Expression&lt;Func&lt;Employee, bool&gt;&gt; exp= em =&gt; em.EmployeeID &gt; 2;
  </code></pre>
  
  <p>Here the operator <code>'&gt;'</code> is selected by combobox at runtime, and it may be '&lt;', '=', '&lt;>', 'contains' and so on.</p>
  
  <p>My question is,  how to build the expression dynamically with the operator selected?  </p>
  
  <p>One important thing, <strong>no selective statements allowed</strong>, such as 'if' and 'switch'.  </p>
  
  <p>Any answer is appreciated.</p>