fixed #55 cannot enable online registration when civirules is enabled.

CRM/Civirules/Utils/CustomDataFromPre.php

@@ -19,7 +19,10 @@ class CRM_Civirules_Utils_CustomDataFromPre {
     foreach($params as $key => $value) {
       if (stripos($key, 'custom_')===0) {
         list($custom_, $fid, $id) = explode("_", $key, 3);
-        self::setCustomData($objectName, $fid, $value, $id);
+        if (is_numeric($fid)) {
+          // The variable $fid should contain a valid ID which should be a numeric value.
+          self::setCustomData($objectName, $fid, $value, $id);
+        }
       }
     }
   }
@@ -27,6 +30,10 @@ class CRM_Civirules_Utils_CustomDataFromPre {
   private static function setCustomData($objectName, $field_id, $value, $id) {
     $v = $value;
 
+    if (!is_numeric($field_id)) {
+      return; // The parameter $field_id should contain a valid ID which is a numeric value.
+    }
+
     /**
      * Convert value array from
      *   value_a => 1

CRM/Civirules/Utils/CustomField.php

@@ -21,7 +21,9 @@ class CRM_Civirules_Utils_CustomField {
      * @throws CiviCRM_API3_Exception
      */
     public static function isCustomFieldMultiselect($customfield_id) {
+        //var_dump($customfield_id); exit();
         $multi_select_types = self::getMultiselectTypes();
+
         $custom_field = civicrm_api3('CustomField', 'getsingle', array('id' => $customfield_id));
         if (in_array($custom_field['html_type'], $multi_select_types)) {
             return true;