title: How to get value from ParameterExpression?
body: <p>I have a method with the following signature:</p>
  
  <pre><code>void Method(Expression&lt;Func&lt;TSource, IEnumerable&lt;TCollection&gt;&gt;&gt; collectionSelector) {}
  </code></pre>
  
  <p>I need to get the result value of <code>collectionSelector</code> in order to compare the result with another instance of <code>IEnumerable&lt;TCollection&gt;</code>. I'm trying to achieve my objective as in the code below, but I got stuck while I was asked to provide parameter value:</p>
  
  <pre><code>var collectionSelectorFunc = collectionSelector.Compile();
  var collection = collectionSelectorFunc.Invoke(collectionSelector.Parameters[0]./*???*/); 
  </code></pre>
  
  <p>How to put there the actual value of the parameter?</p>