正如您在该链接上看到的：

https://cixme.deniz-tasarim.site/video-upload/

单击提交按钮后，wp表示我的电子邮件无效，但我输入了有效的电子邮件。

Array ( [email_valid] => Email has no valid value )

相关代码：

  if(is_email($email)) {
            $error[\'email_valid\'] = "Email has no valid value";
        }

完整代码：

<?php
/* Template Name: Video Upload */

get_header();

    global $wpdb;

    if ($_POST) {

        $username = $wpdb->escape($_POST[\'txtUsername\']);
        $email = $wpdb->escape($_POST[\'txtEmail\']);
        $password = $wpdb->escape($_POST[\'txtPassword\']);
        $ConfPassword = $wpdb->escape($_POST[\'txtConfirmPassword\']);

        $error = array();
        if (strpos($username, \' \')!==FALSE) {
            $error[\'username_space\'] = "Username has Space";
        }
        if(empty($username)) {
            $error[\'username_empty\'] = "Needed Username must";
        }
        if(username_exists($username)) {
            $error[\'username_exists\'] = "Username already exists";
        }
        if(is_email($email)) {
            $error[\'email_valid\'] = "Email has no valid value";
        }
        if(email_exists($email)) {
            $error[\'email_existence\'] = "Email already exists";
        }
        if (strcmp($password, $ConfPassword) !==0) {
            $error[\'password\'] = "Password didn\'t match";
        }
        if (count($error) == 0) {
            wp_create_user($username,$password,$email);
            echo "User created successfully";
            exit();
        }
        else print_r($error);
    }

?>

        <form method="post">

    <p>
            <label for="txtUsername">Enter Username</label>
        <div>
            <input type="text" id="txtUsername" name="txtUsername" placeholder="Username"/>
        </div>
    </p>

    <p>
        <label for="txtEmail">Enter Email</label>
    <div>
        <input type="email" id="txtEmail" name="txtEmail" placeholder="Email"/>
    </div>
    </p>

    <p>
        <label for="txtPassword">Enter Password</label>
    <div>
        <input type="password" id="txtPassword" name="txtPassword" placeholder="Password"/>
    </div>
    </p>

    <p>
        <label>Enter Confirm Password</label>
    <div>
        <input type="password" id="txtConfirmPassword" name="txtConfirmPassword" placeholder="Confirm Password"/>
    </div>
    </p>
        <input type="submit" name="btnSubmit"/>
</form>

<?php get_footer(); ?>

// code before; incorrect - missing the !
if(is_email($email)) {
    $error[\'email_valid\'] = "Email has no valid value";
}

// code after; working as expected after I added the !
if(! is_email($email)) { // if email is invalid, add the error message
    $error[\'email_valid\'] = "Email has no valid value";
}