title: TYPO3 Extbase Flexform: Get selected flexform value for foreign_table_where
body: <p>Is it possible to get the selected flexform value to customize the following select box? For example, I have a plugin where I have to select the type with a select box. Then the second select box appears, called kategorie, which is based on the selected type.</p>
  
  <p>Pseudo code</p>
  
  <pre><code>&lt;settings.type&gt;
      &lt;TCEforms&gt;
          &lt;onChange&gt;reload&lt;/onChange&gt;
          &lt;label&gt;Type&lt;/label&gt;
          &lt;config&gt;
              &lt;type&gt;select&lt;/type&gt;
              &lt;renderType&gt;selectSingle&lt;/renderType&gt;
              &lt;items type="array"&gt;
              &lt;/items&gt;
              &lt;size&gt;1&lt;/size&gt;
              &lt;minitems&gt;1&lt;/minitems&gt;
              &lt;maxitems&gt;1&lt;/maxitems&gt;
              &lt;foreign_table&gt;tx_test_domain_model_type&lt;/foreign_table&gt;
          &lt;/config&gt;
      &lt;/TCEforms&gt;
  &lt;/settings.type&gt;
  &lt;settings.category&gt;
      &lt;TCEforms&gt;
          &lt;label&gt;Category&lt;/label&gt;
          &lt;config&gt;
              &lt;type&gt;select&lt;/type&gt;
              &lt;renderType&gt;selectSingle&lt;/renderType&gt;
              &lt;items type="array"&gt;
              &lt;/items&gt;
              &lt;size&gt;1&lt;/size&gt;
              &lt;minitems&gt;1&lt;/minitems&gt;
              &lt;maxitems&gt;1&lt;/maxitems&gt;
              &lt;foreign_table&gt;tx_test_domain_model_category&lt;/foreign_table&gt;
              &lt;foreign_table_where&gt; AND tx_test_domain_model_categorie.type = ###REC_FIELD_?settings.type?###&lt;/foreign_table_where&gt;
          &lt;/config&gt;
      &lt;/TCEforms&gt;
  &lt;/settings.category&gt;
  </code></pre>
  
  <p>Thank you for help.
  I'm using TYPO3 7.6.14.</p>