How to hide widget from certain category

Question

I need some way to hide theme built in widget from one category.So when the post is from category X on that post hide that widget. I would use plugin for it, but since it's not drag and drop widget I can't. It's a ticker list which is built inside the theme. I have tried with <?php if(!in_category('X')) : ?> like I disabled one other, but this is <ul> list, and my solution ended with error.

This is the code with example what I've tried, and even tried to change position of this in_category() but no luck. Perhaps it needs to be done inside theme function with filter but i didnt find a way or code for it.

The code in header.php:

<div id="ticker">
<span class="ticker-heading"><?php _e( "Don't Miss", 'mvp-text' ); ?></span>
<ul class="ticker-list">
    <?php if(!in_category('X')) : ?><?php else : ?><?php $recent = new WP_Query(array( 'tag' => get_option('gd_ticker_tags'), 'showposts' => get_option('gd_ticker_num') )); while($recent->have_posts()) : $recent->the_post();?>
    <li><a href="<?php the_permalink() ?>"><?php the_title(); ?></a></li>
    <?php endwhile; ?>
</ul>                       
</div><!--ticker-->

Answer 1

I think you might mean is_category()?

Codex: is_category()

Answer 2

I totally agree with Wrought_steel's answer, that's the correct way. So the correct way is:

is_category()

And your refined code will be:

<div id="ticker">
<span class="ticker-heading"><?php _e( "Don't Miss", 'mvp-text' ); ?></span>
<ul class="ticker-list">
    <?php if(!is_category('X')) : //just to hide something from Cat = X ?>
         <?php $recent = new WP_Query(array( 'tag' => get_option('gd_ticker_tags'), 'showposts' => get_option('gd_ticker_num') ));
         while($recent->have_posts()) : $recent->the_post(); ?>
            <li><a href="<?php the_permalink() ?>"><?php the_title(); ?></a></li>
         <?php endwhile; ?>
    <?php endif; ?>
</ul>                       
</div><!--ticker-->

NO NEED to use an else condition, as you want something to hide if it's NOT the desired category.