我有一个静态 View 类，它从另一个类传递一个字符串。当字符串作为变量传递时它起作用。当我将它更改为常量时，错误是:
[17-Feb-2016 19:08:48 Europe/Berlin] PHP Warning: include(): Failed opening '/Applications/MAMP/htdocs/its_vegan/scripts/back_end/views/template' for inclusion (include_path='.:/Applications/MAMP/bin/php/php7.0.0/lib/php') in /Applications/MAMP/htdocs/its_vegan/scripts/back_end/views/view.php on line 23
class View {
/**
* -------------------------------------
* Render a Template.
* -------------------------------------
*
* @param $filePath - include path to the template.
* @param null $viewData - any data to be used within the template.
* @return string -
*
*/
public static function render( $filePath, $viewData = null ) {
// Was any data sent through?
( $viewData ) ? extract( $viewData ) : null;
ob_start();
include ( $filePath );// error on this line
$template = ob_get_contents();
ob_end_clean();
return $template;
}
}
class CountrySelect {
const template = 'select_template.php'; //the const is template
public static function display() {
if ( class_exists( 'View' ) ) {
// Get the full path to the template file.
$templatePath = dirname( __FILE__ ) . '/' . template; //the const is template
$viewData = array(
"options" => '_countries',
"optionsText" => 'name',
"optionsValue" => 'geonameId',
"value" => 'selectedCountry',
"caption" => 'Country'
);
// Return the rendered HTML
return View::render( $templatePath, $viewData );
}
else {
return "You are trying to render a template, but we can't find the View Class";
}
}
}
有用的是在 CountrySelect 中有这个:
$templatePath = dirname( __FILE__ ) . '/' . static::$template;
为什么模板必须是静态的？我可以将其设为静态常量吗？
最佳答案
你也可以使用self::template
由于类常量是在每个类而不是每个对象级别定义的，static::template 将引用相同的内容，除非您有子类。 (参见 https://secure.php.net/manual/en/language.oop5.late-static-bindings.php)
template 指的是全局常量(例如通过 define('template', 'value');)
关于PHP连接变量与常量，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/35464545/