title: foreach after Linq query on a datatable not working
body: <p>I have a LINQ query in C# which runs on a datatable that is generated from a SQL Server exectution:</p>
  
  <pre><code>DataTable dtSubjects = db.ExecuteDataTable();
              var subjectsWithoutParent = from row in dtSubjects.AsEnumerable() 
                                          where row["ParentID"] != DBNull.Value &amp;&amp; row.Field&lt;int&gt;("ParentID") == 0 
                                          select row;
  </code></pre>
  
  <p>Afterwards, there's a foreach that should run on each DataRow returned from the the LINQ. However, the foeach code does not run.</p>
  
  <pre><code>foreach (DataRow rowSubject in subjectsWithoutParent)
              {
                  rowSubject["ParentID"] = DBNull.Value;
              }
  </code></pre>
  
  <p>The Datatable has rows on it, and as far as I can tell subjectsWithoutParent gets at least one row from the LINQ. </p>
  
  <p>Any ideas?</p>