如何阻止两个回声出现(php） - How to stop both echos appearing (php)

while ($stmt->fetch()) {
    if ($teacherusername == $dbTeacherUsername && $teacherpassword == $dbTeacherPassword) {
        if ($dbActive == 1) {
            $loggedIn = true;
        } else if ($dbActive == 0) {
            $loggedIn = false;
            echo "You Must Activate Your Account from Email to Login";
        }
    }
}
if ($loggedIn == false && $_POST) {
    echo "The Username or Password that you Entered is not Valid. Try Entering it Again";
}

在上面的代码中，我在显示消息时遇到问题，我似乎无法弄清楚我做错了什么。如果用户输入了错误的密码或用户名，则会显示消息

"The Username or Password that you Entered is not Valid. Try Entering it Again" .

这很好，但如果 $dbActive = 0，它应该只显示消息

You Must Activate Your Account from Email to Login .

但相反，当发生这种情况时，它会显示两条消息，因此它会显示

You Must Activate Your Account from Email to LoginThe Username or Password that you Entered is not Valid. Try Entering it Again .

我知道为什么会这样，但我似乎想不通。如果 $dbActive = 0，如何阻止它显示两条消息？

你似乎以一种非常奇怪的方式这样做。

while($stmt->fetch()) {

因此，您正在循环访问数据库中的整个结果列表，检查每个结果以查看它们是否与用户的详细信息匹配。为什么不在查询本身中包含详细信息？这样，您只需要检查来自数据库的返回 - 如果您得到返回的结果，您就知道这是一个有效的登录名;如果没有内容，您可以显示"登录无效"消息。

一旦您知道自己获得了有效的结果，就可以检查该帐户是否需要激活。

在伪代码中：

if ($stmt->fetch()) {
    if ($row->$dbActive) {
        # valid login
    } else {
        # needs activation
    }
} else {
    # invalid login
}

你的代码非常清楚地解释了一切：

while($stmt->fetch()) {
    if ($teacherusername == $dbTeacherUsername && $teacherpassword == $dbTeacherPassword) {
        if ($dbActive == 1){
            $loggedIn = true;
        } else if ($dbActive == 0) {

            $loggedIn = false;  
/****************************
 *
 * at this point, $loggedIn == false.
 *
 ****************************/

            echo "You Must Activate Your Account from Email to Login";
        }
    }
}
/****************************
 *
 * at this point, $loggedIn == false.
 *
 * since $loggedIn == false and $_POST is truthy, your if statement will get entered.
 *
 ****************************/
if ($loggedIn == false && $_POST) {
    echo "The Username or Password that you Entered is not Valid. Try Entering it Again";
}

那么我们如何解决这个问题呢？容易！我们添加另一个变量来声明用户是否处于活动状态。

$active = true;
.
.
.
if ($dbActive == 0) {
    $loggedIn = false;
    $active = false;
    echo "You Must Activate Your Account from Email to Login";
}
.
.
.
if (!$loggedIn && $active && isset($_POST['formInputName']) {
    echo "The Username or Password that you Entered is not Valid. Try Entering it Again";
}

这个逻辑可以更简单

从：

if ($dbActive == 1){
    $loggedIn = true;
} else if ($dbActive == 0) {
    $loggedIn = false;
    echo "You Must Activate Your Account from Email to Login";
}

自：

if ($dbActive == 1){
    $loggedIn = true;
} else{
    $loggedIn = false;
    echo "You Must Activate Your Account from Email to Login";
}

和您的最后条件

if ($loggedIn == false && isset($_POST['somefield']) {
    echo "The Username or Passwor...";
}

if ($loggedIn == false && !empty($_POST) && $dbActive != 0) {
    echo "The Username or Password that you Entered is not Valid. Try Entering it Again";
}