如何在codeigniter中的单个Input（form）中验证多个值（值的数组）

Question

这是html部分，当我添加更多电子邮件ID时，只有第一封电子邮件正在验证，其余电子邮件即使不正确也会视为正常

                 <form action="<?php echo base_url()?>index.php/EMail/show_email">
                              <div class="form-group">
                                  <label for="exampleInputEmail1">To :</label>
                           <input  type="email" name="toa[]" ng-model="to"  placeholder="To" class=" tagsinput" value="ss" />


                              </div>
                                 <div class="form-group">
                                  <label for="exampleInputEmail1">Subject :</label>
                                  <input type="text" class="form-control" ng-model="sub" name="suba" id="exampleInputEmail1" placeholder="Subject">
                                                           <div>{{sub}}</div>
                              </div>
                              <div class="form-group">
                                  <label for="exampleInputEmail1">CC :</label>
                                  <input type="text" class="form-control" ng-model="to" name="cca" id="exampleInputEmail1" placeholder="CC">
                                                           <div>{{to}}</div>
                              </div>
                               <div class="form-group">
                                  <label for="exampleInputEmail1">BCC:</label>
                                  <input type="text" class="form-control"  name="bcca" id="exampleInputEmail1" placeholder="BCC">
                              </div>

                                    <div class="form-group ">
                                      <label for="ccomment" class="control-label">Message</label>

                                          <textarea class="form-control " id="ccomment" name="msg" required></textarea>

                                  </div>

                              <div class="form-group">
                                  <label for="exampleInputFile">File input</label>
                                  <input type="file" id="exampleInputFile">
                                  <p class="help-block">Example block-level help text here.</p>
                              </div>
                              <div class="checkbox">
                                  <label>
                                      <input type="checkbox"> Check me out
                                  </label>
                              </div>
                              <input type="submit" onclick="mail()" class="btn btn-primary" value="Send"/>
                              <button type="submit" class="btn btn-Success">Draft</button>
                          </form>

这是我的控制器，“toa”是我在图片中提到的那个字段

    function show_email(){
    $this->form_validation->set_rules("toa[]","To","valid_email");
    $this->form_validation->set_rules("cca","CC ","valid_email");
    $this->form_validation->set_rules("suba","Subject","required");
    $this->form_validation->set_rules("bcca","bcc","valid_email");
    $this->form_validation->set_rules("msg","Message","required");
    if($this->form_validation->run()==FALSE){
    $data["title"]="EMail";
    $this->load->view('header',$data);
    $this->load->view('sidebar');
    $this->load->view('Mail/mail');

    }else{  
    //finish 

    $ccdata=$this->input->post("cca");
    $bccdata=$this->input->post("bcca");
    $sub=$this->input->post("suba");
    $ms=$this->input->post("msg");
    $dataa["username"]="MyProject";
    $dataa["msg"]=$ms;
    $msg=$this->load->view('Email_Temp/mail',$dataa,TRUE);
    $todata=explode(",",$data);

    print_r($todata[0]);
    //$this->SendEmail($todata,$ccdata,$bccdata,$msg,$sub);
   }
}

[Image]这是我要验证的字段（到）