[FEATURE] Add custom controller error message

Classes/Controller/FeElectionController.php

 <?php
+
 namespace TYPO3\Election\Controller;
 
 /*
@@ -167,7 +168,7 @@ class FeElectionController extends ActionController
     public function showAction(Election $election)
     {
         $this->view->assign('election', $election);
-        $this->view->assign('results',$election->getElectedNomineesAndVotes());
+        $this->view->assign('results', $election->getElectedNomineesAndVotes());
     }
 
 
@@ -187,4 +188,18 @@ class FeElectionController extends ActionController
     {
         return '';
     }
+
+    /**
+     * A template method for displaying custom error flash messages, or to
+     * display no flash message at all on errors. Override this to customize
+     * the flash message in your action controller.
+     *
+     * @return string|boolean The flash message or FALSE if no flash message should be set
+     * @api
+     */
+    protected function getErrorFlashMessage()
+    {
+
+        return LocalizationUtility::translate(get_class($this) . '->' . $this->actionMethodName . '()', 'election');
+    }
 }

Resources/Private/Language/locallang.xlf

@@ -497,12 +497,17 @@
             <!-- FE ELECTION VOTING VALIDATION-->
 
             <trans-unit id="validator.fe.election_voting.election_voting_object.to_many_nominees">
-                <source>To many votes</source>
+                <source>To many votes. Please choose only the allowed numbers of nominees.</source>
             </trans-unit>
             <trans-unit id="validator.fe.election_voting.election_voting_object.not_an_object">
                 <source>The received votes are not in a valiid format</source>
             </trans-unit>
 
+            <!-- FE ELECTION VOTING ACTION ERRORS-->
+            <trans-unit id="TYPO3\Election\Controller\FeElectionController->submitVoteAction()">
+                <source>Your voting can not be updated. Please check all messages.</source>
+            </trans-unit>
+
         </body>
     </file>
 </xliff>

Resources/Private/Templates/FeElection/Vote.html

@@ -14,10 +14,32 @@
 			{electionInvitation.electionCircular.election.numberOfVotes} nominees
 		</f:translate>
 	</p>
+
+	<f:form.validationResults>
+		<f:if condition="{validationResults.flattenedErrors}">
+
+			<f:for each="{validationResults.flattenedErrors}" as="errors" key="propertyPath">
+				<ul class="typo3-messages">
+					<f:for each="{errors}" as="error">
+						<li class="alert alert-danger">
+							<p class="alert-message">{error}. <br>
+								<small> Code: {error.code}</small>
+							</p>
+						</li>
+					</f:for>
+				</ul>
+			</f:for>
+
+		</f:if>
+	</f:form.validationResults>
+
 	<f:form action="submitVote" object="{electionVoting}" objectName="electionVoting">
 		<f:form.hidden property="electionInvitation" value="{electionInvitation}"/>
 		<f:render partial="Model/Nominee/VoteList"
 				  arguments="{nominees:electionInvitation.electionCircular.election.nominees}"/>
-		<f:form.submit value="vote"/>
+		<div class="d-flex justify-content-center">
+			<f:form.submit class="btn btn-success float-md" value="vote"/>
+		</div>
 	</f:form>
+	<hr>
 </f:section>