通过递归调用函数从数据库检索数据后动态填充菜单

Question

我正在为我的大学项目建立一个网站，并决定创建首页。在它上面，我尝试通过表示父类别并通过递归调用一个函数来动态填充类别和子类别来显示菜单，该函数通过从数据库获取数据来执行相同的操作。但是，结果仅显示主菜单或父菜单，不显示子类别。我不知所措。 php代码如下所示。

<?php
session_start();
include("connection.php");
$a=0;
if(isset($_SESSION["valid_user"]))
{
    echo "WELCOME ";
    echo $_SESSION["valid_user"];

    $name = $_SESSION["valid_user"];

    $sqllist   = "select * from category order by category_name";
    $rscatlist = mysql_query($sqllist);

    $catid1 = "";
    $opt    = "";

    while($rowcatlist = mysql_fetch_array($rscatlist))
    {
        $catid1  = $rowcatlist["category_id"];
        $catname = $rowcatlist["category_name"];
        $opt .= "<option value='$catid1'>$catname</option>";    
    }

    $sql1 = "select * from register where email_id='$name'" ;
    $rs1  = mysql_query($sql1);
    $row  = 0;
    $row1 = "";

    while($row1=mysql_fetch_array($rs1))
    {
        $row = $row1["admin"];
    }

    if($row==1)
    {
        echo "&nbsp &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp<a href='admin/usermanagement/index.php'>Management Services </a> &nbsp ";
    }
    echo "<p align='right'><a href='logout.php'><font size='3'>logout</font></a></p>"."<br>" ."<br/>";
}
else
{
    echo "<p align='right'><a href='register.php'><font size='3'>Register</font></a> or <a href='login.php'><font size='3'>Login</font></a></p>"."<br/>"."<br/>";
}

$tbl = "";

$cat_id = 0;
$tbl = recursive($tbl,$cat_id);

function recursive($tbl,$cat_id)
{
    $sql = "select * from category where parent_id='$cat_id'";
    $rs  = mysql_query($sql);
    $tbl.="<ul>";
    while($row=mysql_fetch_array($rs))
    {
        $tbl .= "<li><a href='product.php?category_id=$row'[category_id]'>$row[category_name]</a>";
        $sql1 = "select * from category where parent_id=$row'[category_id]'";
        $rs1  = mysql_query($sql1);

        while($row1 = mysql_fetch_array($rs1))
        {  
            recursive($tbl,$row["category_id"]);
        }

        $tbl.="</li>";
    }  
    $tbl.="</ul>";
    return $tbl;
}


?>

Answer 1

在定义该函数之前调用 recursive() 函数似乎很奇怪。似乎很奇怪的是，您仅为 $cat_id 0 调用该函数。您是否需要循环遍历所有主级类别 ID 并将它们也传递到该函数中？

天啊，有没有人教过你评论你的代码；）