Question

尝试添加第4个else语句，但它无效。无法找到有效的在线示例。前3个陈述有效，但不是第4个。应该是If，elseif，elseif，else还是If，elseif，else，else？

if(empty($fromName) or empty($fromEmail) or empty($subject) or empty($comments)) {
    echo 'You cannot submit the form with empty fields. Please correct the form and resubmit.';
    return false;
}
elseif($fieldDelete == "Delete this text!"){    
    $msg ="Delete the contents of the fourth field before submitting.";
    print $msg;
}
else {
    $flgchk = mail ("$to", "$subject", "$message", "$headers"); 
    $imgfile = "images/NatMap logo2.gif"; 
    $handle = fopen($filename, "r");
    $imgbinary = fread(fopen($imgfile, "r"), filesize($imgfile));   
    echo '<img src="data:image/gif;base64,' . base64_encode($imgbinary) . '" width=427 height=72 />';
    echo "\n<br />\n<br />Thank You!  An e-mail has been sent to the National Map web team and they will get back to you in the next 24-48 hours.";
}

else ($fieldDelete == "Delete this text!"){ 
    $msg ="Delete the contents of the fourth field before submitting.";
    print $msg;
     }

Answer 1

上一次if声明没有else。它看起来应该类似于：

if (condition1) {
    /* ... */
}
elseif (condition2) {
    /* ... */
}
elseif (condition3) {
    /* ... */
}
else {
    /* ... */
}

Answer 2

$ fromName ==您无法将else加入else。将其更改为else if。例如：

if(empty($fromName) or empty($fromEmail) or empty($subject) or empty($comments)) {
    echo 'You cannot submit the form with empty fields. Please correct the form and resubmit.';
    return false;

}elseif($fieldDelete == "Delete this text!"){    
    $msg ="Delete the contents of the fourth field before submitting.";
    print $msg;

}elseif($fromName == "Curtisvien" || $fromName ==  "RichardMark" || $fromName == "Thomastymn"){ 

    $msg ="You are blocked."; print $msg;   

}else{
    $flgchk = mail ("$to", "$subject", "$message", "$headers"); 
    $imgfile = "images/NatMap logo2.gif"; 
    $handle = fopen($filename, "r");
    $imgbinary = fread(fopen($imgfile, "r"), filesize($imgfile));   
    echo '<img src="data:image/gif;base64,' . base64_encode($imgbinary) . '" width=427 height=72 />';
    echo "\n<br />\n<br />Thank You!  An e-mail has been sent to the National Map web team and they will get back to you in the next 24-48 hours.";
}

Answer 3

你不能使用其他两次。如下所示，将第二个最后一个更改为else，如下所示：

if(empty($fromName) or empty($fromEmail) or empty($subject) or empty($comments)) {
    echo 'You cannot submit the form with empty fields. Please correct the form and resubmit.';
    return false;
}
elseif($fieldDelete == "Delete this text!"){    
    $msg ="Delete the contents of the fourth field before submitting.";
    print $msg;
}
elseif {
    $flgchk = mail ("$to", "$subject", "$message", "$headers"); 
    $imgfile = "images/NatMap logo2.gif"; 
    $handle = fopen($filename, "r");
    $imgbinary = fread(fopen($imgfile, "r"), filesize($imgfile));   
    echo '<img src="data:image/gif;base64,' . base64_encode($imgbinary) . '" width=427 height=72 />';
    echo "\n<br />\n<br />Thank You!  An e-mail has been sent to the National Map web team and they will get back to you in the next 24-48 hours.";
}

else ($fieldDelete == "Delete this text!"){ 
    $msg ="Delete the contents of the fourth field before submitting.";
    print $msg;
     }

Answer 4

这不是写入.... elseif ... else语句的正确方法。你应该写下面的内容：

if()
{
  //statement;
}elseif()
{
  //statement;
}elseif()
{
   if()
   {
     //Nested Statement;
   }else{
     //Nested Statement;
   }
}else{
  //If all of above is false then this will execute ;
}

在那里你可以使用相同的进程使用任意数量的elseif条件。

Answer 5

也许您正在尝试这样做：

if (condition1) {
    do_this;
} else {
    if (condition2) {
        do_that;
    } else {
        do_something_else;
    }
}

Answer 6

if(empty($fromName) or empty($fromEmail) or empty($subject) or empty($comments)) {
    echo 'You cannot submit the form with empty fields. Please correct the form and resubmit.';
    return false;
}
elseif($fieldDelete == "Delete this text!"){    
         $msg ="Delete the contents of the fourth field before submitting.";
         print $msg;
    }
elseif  (($fromName == "Curtisvien") || ($fromName == "Thomastymn") || ($fromName == "RichardMark")) {
        $msg ="You are blocked.";
        print $msg; 
}

    else {
            $flgchk = mail ("$to", "$subject", "$message", "$headers");
            $imgfile = "images/NatMap logo2.gif";
            $handle = fopen($filename, "r");
            $imgbinary = fread(fopen($imgfile, "r"), filesize($imgfile));   
            echo '<img src="data:image/gif;base64,' . base64_encode($imgbinary) . '" width=427 height=72 />';
            echo "\n<br />\n<br />Thank You!  An e-mail has been sent to the National Map web team and they will get back to you in the next 24-48 hours.";
    }

如果是其他声明

6 个答案: