联系表格与复选框几乎工作

I am having trouble displaying the correct answer/value picked in the contact form. The email received will only show C as an answer and not the picked choice.

<tr>
      <td><label for="gategory">Lemosine</label></td>
      <td><input type="checkbox" name="carchoice[]" value="A" /><td>
  </tr>
  <tr>
      <td><label for="gategory">Mini</label></td>
      <td><input type="checkbox" name="carchoice[]" value="B" /></td>
  </tr>
  <tr>
      <td><label for="gategory">Van</label></td>
      <td><input type="checkbox" name="carchoice[]" value="C" /></td>
  </tr>
  <tr>    
      <td><label for="gategory">Off-Road</label></td>
      <td><input type="checkbox" name="carchoice[]" value="D" /></td>
  </tr>
  <tr>
      <td><label for="gategory">Station-car</label></td>
      <td><input type="checkbox" name="carchoice[]" value="E" /></td>
  </tr>

And the PHP code

$check_box_values = "Check box value: ";
  if(isset($_POST['carchoice'])){
    foreach($_POST['carchoice'] as $value){
    $check_box_values .= $value;
    $check_box_values .= ', ';
  }
}


$msg=
  'Name:    '.$_POST['name'].'<br />
  Email:    '.$_POST['email'].'<br />
  IP:   '.$_SERVER['REMOTE_ADDR'].'<br /><br />

  IP:   '.$check_box_values['carchoice[]'].'<br /><br />

  Message:<br /><br />

  '.nl2br($_POST['message']).'

';

This is what i get in the email

Name:   awdawd aw
Email:  adasda@live.dk
IP:         195.249.185.254

IP:         C

Message:

awdawdawdd awd awdawd awd awd

Don't understand what i going wrong here?

The value of check box is set as 'C' so C will be fetched, as you have labels on each try giving the label name in checkbox value.

As mentioned in the comments, you're trying to access properties of $check_box_values as if it were an array, when in fact, it's a string. As a result, PHP will return the character at the position specified between the square brackets, as this is also a string, it tries to cast it as integer, resulting in 0 (so it's basically returning the character at position 0 in $check_box_values which is C).

Read: String access and modification by character

Also, you don't need to loop to build the string of values, you can use implode():

if (isset($_POST['carchoice'])) {
    $val = implode(', ', $_POST['carchoice']);
    $check_box_values = "Check box value(s): " . $val;
}