Keep the selected value after the form submission [duplicate] - php

Question

This question already has answers here:
Keep values selected after form submission
(12 answers)
Closed 4 months ago.
I have the selection menu which takes the value from the txt file. I want the selected value to remain selected even after the form submission.
<?php
$filename = 'select.txt';
$eachlines = file($filename, FILE_IGNORE_NEW_LINES);
?>
<form action="#" method="post">
<select id="toolchain" name="toolchain" onchange='this.form.submit()'>
<option selected value="base">Please Select</option>
<?php foreach($eachlines as $lines){
echo "<option value='".$lines."'>$lines</option>";
}?>
</select>
</form>
For keeping the value selected,I tried this:
<?php foreach($eachlines as $lines){
echo "<option value='".$lines."'" if($_POST['$lines']) echo $_POST['$lines'];">$lines</option>";
}?>
But it is not working, may be I am using echo inside the echo. Please correct me.

Answer 1

You can use this code. Although I haven't tested the code but let me share my logic with you to make you a better understanding of it. I have added a condition that if the form is submitted then it should display the form with $_POST['toolchain'] selected otherwise it should display it in normal ways.
<?php
$filename = 'select.txt';
$eachlines = file($filename, FILE_IGNORE_NEW_LINES);
if(isset($_POST['toolchain'])
{
?>
<form action="#" method="post">
<select id="toolchain" name="toolchain" onchange='this.form.submit()'>
<option selected value="<?php echo $_POST['toolchain']; ?>"><?php echo $_POST['toolchain']; ?></option>
<?php foreach($eachlines as $lines){
if($lines!=$_POST['toolchain'])
echo "<option value='".$lines."'>$lines</option>";
}?>
</select>
</form>
<?php }
else{
?>
<form action="#" method="post">
<select id="toolchain" name="toolchain" onchange='this.form.submit()'>
<option selected value="base">Please Select</option>
<?php foreach($eachlines as $lines){
echo "<option value='".$lines."'>$lines</option>";
}?>
</select>
</form>
<?php }
?>
It's a normal but a lengthy way. You can also add a condition inside form. If the form is submitted mean if(isset($_POST['toolchain'])) then you can make the option selected for the $_POST['toolchain'] inside foreach loop
Update
I have put the condition inside the form. Kindly update if you face any error as I haven't tested the code
<?php
$filename = 'select.txt';
$eachlines = file($filename, FILE_IGNORE_NEW_LINES);
?>
<form action="#" method="post">
<select id="toolchain" name="toolchain" onchange='this.form.submit()'>
<?php if(isset($_POST['toolchain']))
{
?>
<option value="base">Please Select</option>
<?php foreach($eachlines as $lines){
if($_POST['toolchain']==$lines))
{
echo "<option selected value='".$lines."'>$lines</option>";
}
else {
echo "<option value='".$lines."'>$lines</option>";
}
}
}
else {
?>
<option selected value="base">Please Select</option>
<?php foreach($eachlines as $lines){
echo "<option value='".$lines."'>$lines</option>";
}
}
?>
</select>
</form>