Cannot implicitly convert type 'string' to 'system.web.mvc.selectlistgroup'
<p>Just so I don't have to write out another example to show what I am looking for.
Please reference this <a href="https://stackoverflow.com/questions/36411560/create-dropdownlist-using-iteration-loop?noredirect=1#comment60466746_36411560">example</a>.</p>

<p>Using that example of a table in the database, I want to use the <code>Category</code> as the <em>subtitle</em> (for lack of better words) in a nested dropdownlist.</p>

<p>So here is what I have so far:</p>

<pre><code>List&lt;SelectListItem&gt; lstAssignments = new List&lt;SelectListItem&gt;();

        using(var context = new databaseconnectionstring()/*fake connection string name*/)
        {
            List&lt;table1&gt; lstActivity = context.table1.Where(x =&gt; x.deleted == false).ToList();

            foreach(table1 activity in lstActivity)
            {
                SelectListItem item = new SelectListItem() { Text = activity.text, Value = activity.ID.ToString(), Group = activity.subcategory };
            }
</code></pre>

<p>I am receiving an error underneath the <code>Group = activity.subcategory</code>.</p>

<p><code>Cannot implicitly convert type 'string' to 'system.web.mvc.selectlistgroup'</code></p>

<p>The <code>subcategory</code> property was purposefully created to distinguish the dropdownlist (same as <code>Category</code> in the referenced link)</p>

<p>How do I convert the <code>subcategory</code> to what it is asking for?</p>