Question

我的代码有什么问题，每当我试图删除一条记录时给出警告信息.....请帮帮我

警告：无法修改标头信息 - 已发送的标头（输出从C：\ xampp \ htdocs \ CMS \ admin \ Categories.php：10开始）第181行的C：\ xampp \ htdocs \ CMS \ admin \ Categories.php

<div id="wrapper">

    <!-- Navigation -->

<?php include "includes/Navigation.php";?>


        <!-- Top Menu Items -->
        <ul class="nav navbar-right top-nav">
            <li><a href="../index.php"> Home Page </a></li>

                   <li class="dropdown">
                <a href="#" class="dropdown-toggle" data-toggle="dropdown"><i class="fa fa-user"></i> John Smith <b class="caret"></b></a>
                <ul class="dropdown-menu">
                    <li>
                        <a href="#"><i class="fa fa-fw fa-user"></i> Profile</a>
                    </li>

                    <li class="divider"></li>
                    <li>
                        <a href="#"><i class="fa fa-fw fa-power-off"></i> Log Out</a>
                    </li>
                </ul>
            </li>
        </ul>
        <!-- Sidebar Menu Items - These collapse to the responsive navigation menu on small screens -->
        <div class="collapse navbar-collapse navbar-ex1-collapse">
            <ul class="nav navbar-nav side-nav">
                <li>
                    <a href="index.html"><i class="fa fa-fw fa-dashboard"></i> Dashboard</a>
                </li>

                <li>
                    <a href="javascript:;" data-toggle="collapse" data-target="#posts_dropdown"><i class="fa fa-fw fa-arrows-v"></i> posts <i class="fa fa-fw fa-caret-down"></i></a>
                    <ul id="posts_dropdown" class="collapse">
                        <li>
                            <a href="#">view all pasts</a>
                        </li>
                        <li>
                            <a href="#">add posts</a>
                        </li>
                    </ul>
                </li>

                <li>
                    <a href="bootstrap-grid.html"><i class="fa fa-fw fa-wrench"></i>  Categories</a>
                </li>


                <li>
                    <a href="blank-page.html"><i class="fa fa-fw fa-file"></i> Comments </a>
                </li>


                 <li>
                    <a href="javascript:;" data-toggle="collapse" data-target="#demo"><i class="fa fa-fw fa-arrows-v"></i> Users <i class="fa fa-fw fa-caret-down"></i></a>
                    <ul id="demo" class="collapse">
                        <li>
                            <a href="#">Dropdown Item</a>
                        </li>
                        <li>
                            <a href="#">Dropdown Item</a>
                        </li>
                    </ul>
                </li>


                <li>
                    <a href="index-rtl.html"><i class="fa fa-fw fa-dashboard"></i> Profile</a>
                </li>
            </ul>
        </div>



        <!-- /.navbar-collapse -->
    </nav>

    <div id="page-wrapper">

        <div class="container-fluid">




            <!-- Page Heading -->
            <div class="row">
                <div class="col-lg-12">
                    <h1 class="page-header">
                        Welcome to Admin
                        <small> Rajsekhar</small>
                    </h1>

                    <div class="col-xs-6">
                        <?php 

                            if(isset($_POST['submit']))
                            {
                                $cat_title = $_POST['cat_title'];

                                if ($cat_title == "" || empty($cat_title)) {
                                    # code...

                                    echo "this field should not be empty ";
                                } else {

                                    $query = "INSERT INTO category(cat_title) VALUES ('{$cat_title}')";
                                    $create_cat_query = mysqli_query($connection,$query);

                                    if(!$create_cat_query){

                                        die('query failed' . mysqli_error($connection));
                                    }

                                }

                            }
                         ?>
                        <form action="" method="POST"> 
                            <div class="form-group">

                                <label for="cat-title">Add Category</label>
                                <input type="text" class="form-control" name="cat_title">
                            </div>

                            <div class="form-group">
                                <input type="submit" name="submit" class="btn btn-primary" value="Add Category">
                            </div>

                        </form>
                    </div>


                    <!-- Add category form -->
                    <div class="col-xs-6">

                    <table class="table table-bordered table-hover">
                    <thead>
                        <tr>
                            <th>Id</th>
                            <th>category title</th>
                        </tr>
                    </thead>
                    <tbody>
                     <?php

                        $query = "SELECT * FROM category;";
                        $slect_all_category = mysqli_query($connection,$query);
                        while($row = mysqli_fetch_assoc($slect_all_category)){

                        $cat_id = $row['cat_id'];
                        $cat_title = $row['cat_title'];
                        echo "<tr>";
                        echo "<td> {$cat_id}</td>";
                        echo "<td> {$cat_title}</td>";
                        echo "<td> <a href = 'Categories.php?delete={$cat_id}'> Delete </a>";
                        echo "</tr>";
                        }
                        ?>
                        <tr>

                        </tr>                     
                    </tbody>
                    </table>


                    <?php 

                        if(isset($_GET['delete']))
                        {
                            $delete_id = $_GET['delete'];

                            $query = "DELETE FROM Category where cat_id = {$delete_id} ";

                            $delete_query = mysqli_query($connection,$query);

                        header("Location: Categories.php");    

                            if(!$delete_query)
                            {
                                die('Query Failed' . mysqli_error($connection) );
                            }


                        }

                    ?>



                    </div>
                </div>
            </div>
            <!-- /.row -->

        </div>
        <!-- /.container-fluid -->

    </div>
    <!-- /#page-wrapper -->

Answer 1

在页面开头移动你的帖子逻辑。

一旦脚本的html部分启动，它会自动开始将数据推送到浏览器，响应的标题应该首先出现。然后你包括一些可能想要向浏览器返回错误的php文件，但输出已经开始，所以标题不能被修改，所以php给出了这个错误

<?php 

                        if(isset($_GET['delete']))
                        {
                            $delete_id = $_GET['delete'];

                            $query = "DELETE FROM Category where cat_id = {$delete_id} ";

                            $delete_query = mysqli_query($connection,$query);

                        header("Location: Categories.php");    

                            if(!$delete_query)
                            {
                                die('Query Failed' . mysqli_error($connection) );
                            }


                        }

                    ?>

//rest of the page

警告：无法修改标题信息，我的代码有什么问题

1 个答案: