is it possible to add a variable inside the isset $_post['submit'] - php

Question

Is it possible to do something like this?
if (isset($_POST['Submit_'.$_POST['ID']])) {
}
or
if (isset($_POST['Submit_' + $_POST['ID']])) {
}
I want to do this so i can get a different submit button for all the posts, because i got a comment system, inside a posts system.. so on all the posts its a new submit button.
submitbutton is made like this:
echo "<button type='submit' class='commentbtn' name='commentSubmit_".$row['ID']."'></button>
i have checked that all the buttons gets a different name, so its just the other thing i dont get to work.
comment form:
echo "<div class='commentform'><form id='comment_form_".$row1['sid']."' action='".setComment($conn)."' method='POST'>
<textarea name='commentText' class='commenttext' placeholder='Comment this..'></textarea>
<input type='hidden' name='uname' value='".$_SESSION['name']."'>
<input type='hidden' name='uid' value='".$_SESSION['id']."'>
<input type='hidden' name='uimg' value='".$_SESSION['profile_img']."'>
<input type='hidden' name='date' value='".date('Y-m-d H:i:s')."'>
<input type='hidden' name='sid' value='".$row1['sid']."'>
<button class='commentbtn' name='commSubmit_".$row1['sid']."' type='submit' style='border: 0; background: transparent'>
<img src='images/comment-icon.png' height='24'' alt='comment' title='Comment'' />
</button></form></div>";
setComment Function:
function setComment($conn) {
if(isset($_POST['sid']) && isset($_POST['commSubmit_'.$_POST['sid']])){
$uname = $_POST['uname'];
$uid = $_POST['uid'];
$date = $_POST['date'];
$comment = $_POST['commentText'];
$uimg = $_POST['uimg'];
$sid = $_POST['sid'];
$sql = "INSERT INTO status_comments (uid, sid, uname, comment, uimg, date) VALUES ('$uid', '$sid', '$uname', '$comment', '$uimg', '$date')";
$result = mysqli_query($conn, $sql);
}
}
complete setStatus Function with comment form inside:
function getStatus($conn) {
$sql = "SELECT * FROM status ORDER BY sid DESC";
$query = mysqli_query($conn, $sql);
while ($row1 = $query->fetch_assoc()) {
echo "<div class='commentbox'>";
echo "<div class='commentimg'><img src='images/".$row1['commentimg']."' width='50px'></div>";
echo "<div class='namedate'>";
echo $row1['uidname']."<br>";
echo "<div class='commdate'>".$row1['date']."<br><br></div></div><hr>";
echo "<div class='statusmessage'><p>".nl2br($row1['message'])."</p></div>";
echo "<div class='statusimage'><img src='userimages/".$row1['status_image']."'></div>";
echo "<div class='likerow'>";
$result = mysqli_query($conn, "SELECT * FROM status_like WHERE uid=".$_SESSION['id']." and sid=".$row1['sid']."");
if (mysqli_num_rows($result) == 1) {
echo "<span><a href='' class='unlike' id='".$row1['sid']."'><div class='unlike-btn'><img src='images/dislike.png'></div></a><p>| ".$row1['likes']." likes!</p></span>";
} else {
echo "<span><a href='' class='like' id='".$row1['sid']."'><div class='like-btn'><img src='images/like.png'></div></a><p>| ".$row1['likes']." likes!</p></span>";
}
echo "</div>";
echo "<div class='commentform'><form id='comment_form_".$row1['sid']."' action='".setComment($conn)."' method='POST'>
<textarea name='commentText' class='commenttext' placeholder='Comment this..'></textarea>
<input type='hidden' name='uname' value='".$_SESSION['name']."'>
<input type='hidden' name='uid' value='".$_SESSION['id']."'>
<input type='hidden' name='uimg' value='".$_SESSION['profile_img']."'>
<input type='hidden' name='date' value='".date('Y-m-d H:i:s')."'>
<input type='hidden' name='sid' value='".$row1['sid']."'>
<button class='commentbtn' name='commSubmit_".$row1['sid']."' type='submit' style='border: 0; background: transparent'>
<img src='images/comment-icon.png' height='24'' alt='comment' title='Comment'' />
</button></form></div>";
if ($_SESSION['id'] === $row1['uid'] || $_SESSION['usertype'] === 'topadmin'){
echo "<form class='delete-form' method='POST' action='".deleteStatus($conn)."'>
<input type='hidden' name='sid' value='".$row1['sid']."'>
<input type='hidden' name='sid' value='".$row1['sid']."'>
<button type='submit' title='Delete Status' name='statusDelete'>X</button>
</form>
<form class='edit-form' method='POST' action='editcomment.php'>
<input type='hidden' name='sid' value='".$row1['sid']."'>
<input type='hidden' name='uid' value='".$row1['uid']."'>
<input type='hidden' name='date' value='".$row1['date']."'>
<input type='hidden' name='message' value='".$row1['message']."'>
<button type='submit' style='border: 0; background: transparent'>
<img src='images/edit-icon.png' height='10'' alt='edit' title='Edit Status'' />
</button>
</form>";
}
echo "</div>";
}
}

Answer 1

Yes your first expression is correct. Check PHP concatenate for more information. Though I would use following to check form submit.
// check if request method is post
if ($_SERVER['REQUEST_METHOD'] === 'POST') {
// .... your code
}
Additionally, I have had look on your code. I think the error is in form HTML.
echo "<div class='commentform'><form id='comment_form_".$row1['sid']."' action='".setComment($conn)."' method='POST'>
It cause function to run 4 times and recording coment 4 times. Please replace action='#' or action='processComent.php' // location of process code.
Do the same in
<form class='delete-form' method='POST' action='".deleteStatus($conn)."'>
also as same thing will happen while deleting.

Answer 2

Yes, it's possible and your first variant is correct.
Thought a better idea might be make a separate form for each comment field and add the ID as a hidden input.
Something like this:
<form method="post" action="/something">
<textarea name="comment">
<input type="hidden" name="id" value="$row['ID']">
<button type="submit" name="submit"></button>
</form>

Answer 3

I can't really follow the logic in your code, but it seems as if you are over complicating the process... and i assume that your action was not actually pointing to that function as you show, but instead, is pointing to a page with that function ... anyway ... if you have this form
echo "
<div class='commentform'>
<form id='comment_form_".$row1['sid']."' action='setcomment.php' method='POST'>
<textarea name='commentText' class='commenttext' placeholder='Comment this..'></textarea>
<input type='hidden' name='uname' value='".$_SESSION['name']."'>
<input type='hidden' name='uid' value='".$_SESSION['id']."'>
<input type='hidden' name='uimg' value='".$_SESSION['profile_img']."'>
<input type='hidden' name='date' value='".date('Y-m-d H:i:s')."'>
<input type='hidden' name='sid' value='".$row1['sid']."'>
<button class='commentbtn' name='commSubmit_".$row1['sid']."' type='submit' style='border: 0; background: transparent'>
<img src='images/comment-icon.png' height='24'' alt='comment' title='Comment'' />
</button>
</form>
</div>";
and then when that form posts to setcomment.php, something simple like this would work ...
if(isset($_POST['sid']) && isset($_POST['commSubmit_'.$_POST['sid']])){
setComment($conn);
}
function setComment($conn) {
$uname = $_POST['uname'];
$uid = $_POST['uid'];
$date = $_POST['date'];
$comment = $_POST['commentText'];
$uimg = $_POST['uimg'];
$sid = $_POST['sid'];
$sql = "
INSERT INTO
status_comments
(
uid, sid, uname, comment, uimg, date
)
VALUES
(
'".mysqli_real_escape_string($conn,$uid)."',
'".mysqli_real_escape_string($conn,$sid)."',
'".mysqli_real_escape_string($conn,$uname)."',
'".mysqli_real_escape_string($conn,$comment)."',
'".mysqli_real_escape_string($conn,$uimg)."',
'".mysqli_real_escape_string($conn,$date)."'
)";
$result = mysqli_query($conn, $sql);
}