try this

// MOdel
public function getComenForum($id){

            $query = self::getDB()->prepare("select count(*) from komentar WHERE id_forum='$id' ");
//("SELECT * FROM komentar WHERE id_forum='$id' ");
            $query->execute();
            $row= $query->fetch();
        return $row;
    }
//Controller
function forum(){
        session_start();
        if(isset($_SESSION['username'])){
        if($_SESSION['hak_akses']=="user"){
        @$viewModel['comen']= m_user::getComenDepan();
        @$viewModel['pagging']= m_user::Pagging();
        $halaman=$_GET['id'];
        @$viewModel['foto']= m_user::DataFoto();
        @$viewModel['forum']= m_user::getForum($halaman);
            $this->RenderUser($viewModel);
        }else{
                echo "admin tidak boleh mengakses user";
            }
                }else{
                echo "tidak boleh mengakses";
            }
        }
//View
 <div class="row">
                        <?php
foreach($viewModel['forum'] as $row){ ?>
                <div class="col-lg-12 col-md-12 col-sm-12 col-xs-12 forum-item radius-xs">
                    <div class="col-lg-12 forum-text">
                        <img src="<?php echo $row['file'];?>" width="200"class="img-responsive forum-photo" alt="" style='float: left;'>
                        <div class="textcontent">
                            <a href="user/viewForum/<?php echo $row['id_forum'];?>" class="title"><?php echo $row['judul'];?></a><br/>
                            <p class="mini-desc">
                            <?php echo $row['deskripsi'];?>
                            </p>
                            <div class="text-left">
                            <mark><?php echo $row['nama'];?></mark>
                            <mark><i class="fa fa-eye fa-1x"></i> 12</mark> <mark><i class="fa fa-comments fa-1x"></i>   <?php echo $viewModel['comen'];
                                ?></mark>
                            <mark class="user-info"><?php echo $row['username'];?>, <?php echo $row['tanggal'];?></mark>
                            </div>
                        </div>
                    </div>
                </div>
               <?php } ?>