使选定的下拉值必须是粘性的

Question

$service = CityService::getInstance();
$cities = $service->getAllCities(); 
foreach($cities as $city){
    echo"<option value='".$city->CityID."'>".ucfirst($city->CityName)."</option>";
}   

这里的代码我从城市获取列表，我想在下拉列表中选中粘性，我应该在哪里应用“选中”???

Answer 1

假设您的select代码有name="city"。那么在您的$_POST["city"]中将成为所选城市。

因此，当您遍历所有城市时，检查，$_POST["city"]（由用户设置的内容）是否与循环中的当前项目相同：

foreach ($cities as $city) {
    $selected = '';
    if (!empty($_POST["city"]) && $_POST["city"] == $city->CityID) {
        $selected = ' selected="selected"';
    }
    echo"<option value='" . $city->CityID . "'" . $selected . ">" . ucfirst($city->CityName) . "</option>";
}

Answer 2

http://www.w3schools.com/tags/att_option_selected.asp

service = CityService::getInstance();
$cities = $service->getAllCities(); 
foreach($cities as $city){
    echo"<option value='".$city->CityID."' selected>".ucfirst($city->CityName)."</option>";
}