title: Incorporate partial expression in LINQ/SQL query
body: <p>I have an expression that returns a DateTime column in a query.</p>
  <pre><code>Expression&lt;Func&lt;T, DateTime&gt;&gt; GetDateExpression;
  
  GetDateExpression = td =&gt; td.DateShipped;
  </code></pre>
  <p>But now I want to use that expression to form a filter in a SQL query.</p>
  <pre><code>query = query.Where(td =&gt; GetDateExpression(td) &gt;= startDate);
  </code></pre>
  <p>But that won't compile.</p>
  <blockquote>
  <p>error CS1955: Non-invocable member 'DateFilter.GetDateExpression' cannot be used like a method.</p>
  </blockquote>
  <p>Can anyone show me how to construct the where clause above using <code>GetDateExpression</code>?</p>