我正试图为我的学校作业之一写一个代码，但我找不到它不工作的原因。可能是我还没意识到的简单原因。谁能给我指个正确的方向?我试图使一个类生成3下拉框选择日，月和年。第三个函数似乎也有一个无限循环。代码如下，分为两个文件:
文件1:datselect.php
<?php
include ("datselect_functions.php");
$cls = new Dropdown();
$monthname = array(1 => "January", "February", "March", "April", "May", "June",
"July","August", "September", "October", "November", "December");
$today = time();
$f_today = date("M-d-Y",$today);
$func = insert_day();
$func = insert_month($monthname);
//$func = insert_year($today);
echo html_head($f_today);
echo $cls -> getHTML();
echo html_foot();
?>
文件2:datselect_functions.php
<?php
function html_head($f_today) {
return "<html>
<head>
<title>Select a date</title>
</head>
<body>
<div>
Today is ".$f_today."
</div>";
}
class Dropdown {
private $name = "";
private $options = array();
private $selected = "";
public function __construct($name = "") {
$this->name=$name;
}
public function setOption($var,$label) {
$this->options[$var]=$label;
}
public function getHTML() {
$html = "<select name='".$this->name."'>";
var_dump($this->name);
foreach($this->options as $var => $label) {
if ($this->selected=$var) {
$html.= "<option selected value='".$var."'>.$label.</option>";
} else {
$html.= "<option value='".$var."'>.$label.</option>";
}
}
$html.= "</select>";
return $html;
}
}
function html_foot() {
return "</body></html>";
}
function insert_day(){
$ddd = new Dropdown("day");
for($i=1; $i<=31; $i++){
$ddd -> setOption($i, $i);
}
}
function insert_month($monthname){
$ddm = new Dropdown("month");
foreach($monthname as $key => $value) {
$ddm -> setOption($key, $value);
}
}
function insert_year($today){
$currentyear = date("Y", $today);
$ddy = new Dropdown("year");
for($n=$currentyear;$n=$currentyear+3;$n++) {
$ddy -> setOption($n, $n);
}
}
?>
有很多地方会出错。
//this is unnecessary, you now create an empty dropdown and echo it here.
$cls = new Dropdown();
echo $cls -> getHTML();
//instead of this
$func = insert_day();
$func = insert_month($monthname);
//$func = insert_year($today);
//do this
$days = insert_day();
$months = insert_month($monthname);
$years = insert_year($today);
//then make the dropdows appear like this.
echo $days;
echo $months;
echo $years;
//These 3 functions require an extra line of code.
function insert_day(){
$ddd = new Dropdown("day");
for($i=1; $i<=31; $i++){
$ddd -> setOption($i, $i);
}
//add this line to all of these three functions, but change the var name
return $ddd->getHTML();
}
这应该可以解决您的大多数错误，但现在可能会出现一些其他的错误。
你的下拉列表类只是一个生成下拉列表html代码的助手。您需要存储生成的代码或将其输出到某个地方，以便"它工作"。
$func = insert_day(); // 1
$func = insert_month($monthname); // 2
//$func = insert_year($today);
echo html_head($f_today); // 3
echo $cls -> getHTML(); // 4
echo html_foot(); // 5
你正在一步步地做下面的事情:
- 你将日期选择的下拉html代码分配给$func
- 您将月份选择的下拉html代码分配给$func，覆盖从1到1的所有内容。你应该为它使用一个新变量，或者如果你想要的话，在它后面加上
$func .= insert... - 你输出你的标题html
- 你输出一个空的下拉菜单，因为下拉菜单实例$cls没有在任何地方配置选项数组
- 输出页脚html
缺少的是您还应该输出1的结果。和2。后3。此外，insert_year中的无限循环是因为您在for循环中分配了当前年份+ 3，而不是比较它(=与==)。
每个类只有一个文件是很好的风格，但这不是这里的问题。
希望对你有帮助。
"="不是比较，而是设置(使用"=="代替):
if ($this->selected=$var) {
死循环:
for($n=$currentyear;$n=$currentyear+3;$n++) {
:
for($n=$currentyear;$n < $currentyear+3;$n++) {
你的insert_day, insert_month函数没有任何用途。下面我已经更新了你的代码来显示天数，虽然你真的不需要这么多代码。
//dateselect.php
<?php
include ("datselect_functions.php");
$cls = new Dropdown();
$monthname = array(1 => "January", "February", "March", "April", "May", "June", "July",
"August", "September", "October", "November", "December");
$today = time();
$f_today = date("M-d-Y",$today);
$func = $cls->insert_day();
//$func = insert_month($monthname);
//$func = insert_year($today);
echo html_head($f_today);
echo $cls -> getHTML();
//echo html_foot();
?>
//datselect_functions
<?php
function html_head($f_today) {
return "<html>
<head>
<title>
Select a date
</title>
</head>
<body>
<div>
Today is ".$f_today."
</div>";
}
class Dropdown {
private $name = "";
private $options = array();
private $selected = "";
public function __construct($name = "") {
$this->name=$name;
}
public function setOption($var,$label) {
$this->options[$var]=$label;
}
public function getHTML() {
$html = "<select>";
//var_dump($this->options);
foreach($this->options as $var => $label) {
if ($this->selected==$var) {
$html.= "<option selected value='".$var."'>.$label.</option>";
}
else {
$html.= '<option value="'.$var.'">'.$label."</option>";
}
}
$html.= "</select>";
//print_r($html);
return $html;
}
function insert_day(){
for($i=1; $i<=31; $i++){
$this -> setOption($i, $i);
}
}
function html_foot() {
return "</body></html>";
}
}
function insert_month($monthname){
$ddm = new Dropdown("month");
foreach($monthname as $key => $value) {
$ddm -> setOption($key, $value);
}
}
function insert_year($today){
$currentyear = date("Y", $today);
$ddy = new Dropdown("year");
for($n=$currentyear;$n<=$currentyear+3;$n++) {
$ddy -> setOption($n, $n);
}
}
?>