无法在php中设置会话

Question

我无法在php中获取会话变量我已经在主html页面中启动了会话。只有当部分工作时，其他部分的其余部分才会给出任何结果。 在标题部分重新加载页面时，它给我一个错误

  

注意：尝试获取非对象的属性   C：\瓦帕\ WWW \ PHPMailer的\额外\ JS \ post_action.php

post_action.php

   <form method='post' id='submit_form' action="process/upload_new.php?id=<?php echo $id; ?>" enctype="multipart/form-data"> 
    <tr>
       <td class="col-md-4">Upload Image</td> 
        <td class="col-md-8"><input name='post_image' value='<?php echo $rows["post_image"]; ?>' type="file" placeholder="Site Titlebar" class="form-control" />
            <br>
        <input name='submit' id='submit' type="submit" value='Upload Image' class="btn btn-success" />  
        </td>
    </tr>
    <tr>
        <td>
                <p> Image Preview </p>
        </td>
        <td>
            <img src='<?php echo $rows["post_image"]; ?>' width='100px' height='100px' />
        </td>
    </tr>
</form>

过程/ upload_new.php

<?php

if($_FILES['post_image']['name'] != ''){

    $uploaded_file = $_FILES['post_image']['name'];
    $exp = explode(".",$uploaded_file);
    $extension = end($exp);
    $allowed_types = array('jpg',"jpeg","png","gif");
    if(in_array($extension,$allowed_types))
    {
        if(is_uploaded_file($_FILES['post_image']['tmp_name'])){
            $new_name = rand().".".$extension;
            $path = "../images/".$new_name;


            if(move_uploaded_file($_FILES['post_image']['tmp_name'],$path))
            {
                $_SESSION['upload_success'] = "File Uploaded succesfully";
                $db_path = "images/".$new_name;
                $values = ['post_image' => $db_path]; #calling update method to update image;
                $id = $_GET['id'];
                include_once "action_page.php";
                $tablename = 'posts';
                $abc = new Demo();
                $res = $abc->edit($tablename,$values,$id);
                unset($abc);
                $_SESSION['upload_success'] = "File Uploaded succesfully"; 
                //header("location:../post_action.php?id=$id");

            }
            else
                {
                    $_SESSION['upload_error'] = "Something went wrong, file cannot be uploaded"; 
                    //header("location:../post_action.php?id=$id");
                }
        }
        else            
            {
                $_SESSION['upload_error'] = "Cannot upload file"; 
                //header("location:../post_action.php?id=$id");
            }   
    }
    else{
        $_SESSION['upload_warning'] = "Please upload appropriate file type"; 
        //header("location:../post_action.php?id=$id");
    }
}
else
{
    $_SESSION['upload_warning'] = "Please upload file"; 
    header("location:../post_action.php?id=$id");
}