(not all) Data can't reach database - php

Question

I want to send data to my database (group_id, user_id and group_name) but only the first two are getting into the database. When I var_dump $groupinvitation->Invitation_group_name = mysql_real_escape_string($groupname); it gives me the correct group_name. What am I doing wrong?
When I replace '" . $db->conn->real_escape_string($this->Invitation_group_name) . "' with a random word it is working well..
PHP
$groupinvitation = new GroupInvitation();
if (isset($_POST["Accept"])) {
try {
$group_id = mysql_real_escape_string($_POST["group_id"]);
$groupinfo = $group->GetGroupInfoByGroupId($group_id);
$groupname = $groupinfo['group_name'];
$requestnumber = mysql_real_escape_string($_POST['acceptID']);
$groupinvitation->AddAsGroupMember($number, $group_id);
$groupinvitation-> AcceptGroupRequest($requestnumber);
$groupinvitation->Invitation_group_name = mysql_real_escape_string($groupname);
$feedback = "Awesome, You just added a friend!";
} catch(Exception $e) {
$feedback = $e -> getMessage();
}
}
DECLARATIONS:
class GroupInvitation
{
private $m_sGroup_invitation_group_name;
public function __set($p_sProperty, $p_vValue)
{
switch($p_sProperty)
{
case "Invitation_group_name":
$this->m_sGroup_invitation_group_name = $p_vValue;
break;
}
}
public function __get($p_sProperty)
{
switch($p_sProperty)
{
case "Invitation_group_name":
return $this->m_sGroup_invitation_group_name ;
break;
}
}
FUNCTION:
public function AddAsGroupMember($number, $group_id)
{
$db = new Db();
$insert = "INSERT INTO tblgroup_member(
group_id,
user_id,
group_name
) VALUES (
'" . $db->conn->real_escape_string($group_id) . "',
'" . $db->conn->real_escape_string($number) . "',
'" . $db->conn->real_escape_string($this->Invitation_group_name) . "'
)";
$db->conn->query($insert);
}

Answer 1

Try changing
$groupinvitation->AddAsGroupMember($number, $group_id);
$groupinvitation-> AcceptGroupRequest($requestnumber);
$groupinvitation->Invitation_group_name = mysql_real_escape_string($groupname);
to
$groupinvitation->Invitation_group_name = mysql_real_escape_string($groupname);
$groupinvitation->AddAsGroupMember($number, $group_id);
$groupinvitation-> AcceptGroupRequest($requestnumber);
You could be setting the property after the insert.