PHP If / Else语句在While循环中不起作用

Question

I've been working on this bit of code for about an hour and can't seem to figure out why it's not working. Does PHP allow If/Else statements within While loops? I've tried adding different echos to both If/Else statements and the latter (Else) will not show. Is this because I'm trying to use the same variable names?

while($row = mysql_fetch_array($result))

{

//assign variables
$title = $row['title'];
$file_url = $row['file_location'];
$category = $row['category'];
$layout = $row['layout'];


    If ($layout = "vertical")       
    {
        //Page Layout
        $BODYLAYOUT = "vertical_body";
        $GAMECONTAIN = "vertical_gameContain";
        $GAMEWIDTH = "vertical_game";
    }
    Else
    {
        // Page Layout
        $BODYLAYOUT = "horizontal_body";
        $GAMECONTAIN = "horizontal_gameContain";
        $GAMEWIDTH = "horizontal_game";
    }

Answer 1

if ($layout = "vertical")   

should be:

if ($layout == "vertical")   

Otherwise you are assinging a value to $layout of 'vertical' opposed to comparing it's value to see if it's equal to 'vertical'. That assignment will otherwise equal to true, reason the first part runs and the ELSE does not.

One method I use to prevent accidents like this is to put the constant first such as:

if ("vertical" == $layout)   

That way if I miss the other = sign PHP will error, rather than assign the value erroneously.