Les crochets / filtres WordPress s'insèrent avant le contenu ou après le titre

Utilisez simplement lefiltre the_content,parexemple:

 <?php
function theme_slug_filter_the_content( $content ) {
    $custom_content = 'YOUR CONTENT GOES HERE';
    $custom_content .= $content;
    return $custom_content;
}
add_filter( 'the_content', 'theme_slug_filter_the_content' );
?>
 

Engros,vous ajoutez le contenu dumessage après votre contenupersonnalisé,puis vous renvoyez le résultat.

Modifier

Comme le souligne Franky @bueltge dans son commentaire,leprocessusest lemêmepour letitre dumessage; ajoutez simplement unfiltre au hook the_title:

 <?php
function theme_slug_filter_the_title( $title ) {
    $custom_title = 'YOUR CONTENT GOES HERE';
    $title .= $custom_title;
    return $title;
}
add_filter( 'the_title', 'theme_slug_filter_the_title' );
?>
 

Notez que,dans ce cas,vous ajoutez votre contenupersonnalisé après letitre. (Peuimporte lequel;je suisjuste allé avec ce que vous avez spécifié dans votre question.)

Modifier 2

La raisonpour laquelle votreexemple de codene fonctionnepasest que vous ne renvoyez $content que lorsque votre conditionest remplie . Vous devez renvoyer $content,nonmodifié,sous laforme d'un else à votre conditionnel.parexemple:

 function property_slideshow( $content ) {
    if ( is_single() && 'property' == get_post_type() ) {
        $custom_content = '[portfolio_slideshow]';
        $custom_content .= $content;
        return $custom_content;
    } else {
        return $content;
    }
}
add_filter( 'the_content', 'property_slideshow' );
 

De cettefaçon,pour les articles quine sontpas dutype depublication "propriété",$contentest renvoyé,nonmodifié.

Just use the the_content filter, e.g.:

<?php
function theme_slug_filter_the_content( $content ) {
    $custom_content = 'YOUR CONTENT GOES HERE';
    $custom_content .= $content;
    return $custom_content;
}
add_filter( 'the_content', 'theme_slug_filter_the_content' );
?>

Basically, you append the post content after your custom content, then return the result.

Edit

As Franky @bueltge points out in his comment, the process is the same for the post title; simply add a filter to the the_title hook:

<?php
function theme_slug_filter_the_title( $title ) {
    $custom_title = 'YOUR CONTENT GOES HERE';
    $title .= $custom_title;
    return $title;
}
add_filter( 'the_title', 'theme_slug_filter_the_title' );
?>

Note that, in this case, you append your custom content after the Title. (It doesn't matter which; I just went with what you specified in your question.)

Edit 2

The reason your example code isn't working is because you only return $content when your conditional is met. You need to return $content, unmodified, as an else to your conditional. e.g.:

function property_slideshow( $content ) {
    if ( is_single() && 'property' == get_post_type() ) {
        $custom_content = '[portfolio_slideshow]';
        $custom_content .= $content;
        return $custom_content;
    } else {
        return $content;
    }
}
add_filter( 'the_content', 'property_slideshow' );

This way, for posts not of the 'property' post-type, $content is returned, un-modified.

 function property_slideshow( $content ) {
    if ( is_singular( 'property' ) ) {
        $custom_content = do_shortcode( '[portfolio_slideshow]' );
        $custom_content .= $content;
        }
        return $custom_content;
}
add_filter( 'the_content', 'property_slideshow' );
 

Labalise conditionnelle is_singular vérifie si unmessage au singulieresten courss'afficheet vouspermet de spécifier leparamètre $post_types qui dans ce casest unepropriété.

Vouspouvez également consulter do_shortcode

function property_slideshow( $content ) {
    if ( is_singular( 'property' ) ) {
        $custom_content = do_shortcode( '[portfolio_slideshow]' );
        $custom_content .= $content;
        }
        return $custom_content;
}
add_filter( 'the_content', 'property_slideshow' );

The is_singular conditional tag checks if a singular post is being displayed and enables you to specify the $post_types parameter which in this case is property.

Also, you might want to look at do_shortcode