diff --git a/Form/FieldTypeHandler/TextLine.php b/Form/FieldTypeHandler/TextLine.php
index a3fa2e3..3c4dcb5 100644
--- a/Form/FieldTypeHandler/TextLine.php
+++ b/Form/FieldTypeHandler/TextLine.php
@@ -52,11 +52,11 @@ protected function buildFieldForm(
             $minStringLength = $fieldDefinition->validatorConfiguration['StringLengthValidator']['minStringLength'];
             $maxStringLength = $fieldDefinition->validatorConfiguration['StringLengthValidator']['maxStringLength'];
 
-            if ($minStringLength !== false) {
+            if (!empty($minStringLength)) {
                 $lengthConstraints['min'] = $minStringLength;
             }
 
-            if ($maxStringLength !== false) {
+            if (!empty($maxStringLength)) {
                 $lengthConstraints['max'] = $maxStringLength;
             }
 
diff --git a/Tests/Form/FieldTypeHandler/TextLineTest.php b/Tests/Form/FieldTypeHandler/TextLineTest.php
index cda5075..59e657c 100644
--- a/Tests/Form/FieldTypeHandler/TextLineTest.php
+++ b/Tests/Form/FieldTypeHandler/TextLineTest.php
@@ -78,4 +78,36 @@ public function testBuildFieldCreateForm()
         $text = new TextLine();
         $text->buildFieldCreateForm($formBuilder, $fieldDefinition, $languageCode);
     }
+
+    public function testBuildFieldCreateFormWithStringLengthsNull()
+    {
+        $formBuilder = $this->getMockBuilder(FormBuilder::class)
+            ->disableOriginalConstructor()
+            ->setMethods(array('add'))
+            ->getMock();
+
+        $formBuilder->expects($this->once())
+            ->method('add');
+
+        $fieldDefinition = new FieldDefinition(
+            array(
+                'id' => 'id',
+                'identifier' => 'identifier',
+                'isRequired' => true,
+                'descriptions' => array('fre-FR' => 'fre-FR'),
+                'names' => array('fre-FR' => 'fre-FR'),
+                'validatorConfiguration' => array(
+                    'StringLengthValidator' => array(
+                        'minStringLength' => null,
+                        'maxStringLength' => null,
+                    ),
+                ),
+            )
+        );
+
+        $languageCode = 'eng-GB';
+
+        $text = new TextLine();
+        $text->buildFieldCreateForm($formBuilder, $fieldDefinition, $languageCode);
+    }
 }