Silverstripe selected in DropdownField
<p>How can I set a default selected value in <code>Silverstripe</code> using <code>DropdownField</code>. I have list of categories and I want to set a default selected item, but I don't know how to do it. Looking on SS API for DropdownField, there does not exist method for <code>selected</code>.</p>

<p><strong>Here is my code:</strong></p>

<pre><code>DropdownField::create('CategoryID', 'Categories')-&gt;setSource(Category::get()-&gt;map('ID', 'Name'))-&gt;setEmptyString('Chose category'),
</code></pre>