Dynamic two or more levels sub-menu generation in vb6

creationdynamicsubmenuvb6

Friends,
Tell me how to generate more than 1 levels of sub-menu in VB6 at runtime? Explain in brief? Any specific controls are there? But i dont want to use external controls!

Best Solution

You Can Create More than One level of Submenu by using API function

Private Declare Function CreatePopupMenu Lib "user32" () As Long

Private Declare Function AppendMenu Lib "user32" Alias "AppendMenuA" (ByVal hmenu As Long, ByVal wFlags As Long, ByVal wIDNewItem As Long, ByVal lpNewItem As Any) As Long

Private Declare Function GetCursorPos Lib "user32" (lpPoint As POINTAPI) As Long

Private Declare Function TrackPopupMenu Lib "user32" (ByVal hmenu As Long, ByVal wFlags As Long, ByVal X As Long, ByVal Y As Long, ByVal nReserved As Long, ByVal hwnd As Long, lprc As Any) As Long

Private Declare Function DestroyMenu Lib "user32" (ByVal hmenu As Long) As Long

Private Type POINTAPI
    X As Long
    Y As Long
End Type

Dim hmenu As Long, hSubMenu As Long
Private Const MF_STRING = &H0&
Private Const MF_SEPARATOR = &H800&


  hSubMenu = CreatePopupMenu
  AppendMenu hSubMenu, 0, 121, "Sub Menu1"
  AppendMenu hSubMenu, 0, 122, "Sub Menu2"

  hmenu = CreatePopupMenu
  AppendMenu hmenu, 0, 107, "Menu1"

  AppendMenu hmenu, 0, 106, "Menu2"

  AppendMenu hmenu, MF_POPUP, hSubMenu, "Menu3"
  AppendMenu hmenu, MF_POPUP, hSubMenu, "Menu4"

  AppendMenu hmenu, 0, 101, "Menu5"

To display

  If Button = vbRightButton Then
    Dim P As POINTAPI
    GetCursorPos P
    TrackPopupMenu hmenu, 0, P.X, P.Y, 0, hwnd, 0

The menu is not displayed until TrackPopupMenu is called. Its return value can indicate which (if any) menu item was selected. e.g., it could return '107' if "Menu1" was selected.

Quick code example on a gist

Here's the code on a github gist for anyone who wants to get in on the copy paste action.

TL;DR

TL;DR Loop over list, drill down if there's a sub menu, close if we reach the end of the sub menu and menu.

Complete Code explanation

Firstly get the menu items as a flat array:

<?php
$menu_name = 'main_nav';
$locations = get_nav_menu_locations();
$menu = wp_get_nav_menu_object( $locations[ $menu_name ] );
$menuitems = wp_get_nav_menu_items( $menu->term_id, array( 'order' => 'DESC' ) );
?>

Then iterate over the array of the menu items:

<nav>
<ul class="main-nav">
    <?php
    $count = 0;
    $submenu = false;

    foreach( $menuitems as $item ):
        // set up title and url
        $title = $item->title;
        $link = $item->url;

        // item does not have a parent so menu_item_parent equals 0 (false)
        if ( !$item->menu_item_parent ):

        // save this id for later comparison with sub-menu items
        $parent_id = $item->ID;
    ?>

Write the first parent item <li>:

    <li class="item">
        <a href="<?php echo $link; ?>" class="title">
            <?php echo $title; ?>
        </a>
    <?php endif; ?>

Check that this items' parent id matches the stored parent id:

        <?php if ( $parent_id == $item->menu_item_parent ): ?>

Start sub-menu <ul> and set $submenu flag to true for later referance:

            <?php if ( !$submenu ): $submenu = true; ?>
            <ul class="sub-menu">
            <?php endif; ?>

Write the sub-menu item:

                <li class="item">
                    <a href="<?php echo $link; ?>" class="title"><?php echo $title; ?></a>
                </li>

If the next item does not have the same parent id and we have a sub-menu declared then close the sub-menu <ul>

            <?php if ( $menuitems[ $count + 1 ]->menu_item_parent != $parent_id && $submenu ): ?>
            </ul>
            <?php $submenu = false; endif; ?>

        <?php endif; ?>

Again, if the next item in the array does not have the same parent id close the <li>

    <?php if ( $menuitems[ $count + 1 ]->menu_item_parent != $parent_id ): ?>
    </li>                           
    <?php $submenu = false; endif; ?>

<?php $count++; endforeach; ?>

  </ul>
</nav>

Css – Bootstrap dropdown sub menu missing

Bootstrap 5 (update 2021)

Add some JavaScript to prevent the submenu from closing when the parent dropdown is open. This can be done be toggle display:block...

let dropdowns = document.querySelectorAll('.dropdown-toggle')
dropdowns.forEach((dd)=>{
    dd.addEventListener('click', function (e) {
        var el = this.nextElementSibling
        el.style.display = el.style.display==='block'?'none':'block'
    })
})

Bootstrap 5 Multi-level Dropdown - click
Bootstrap 5 Multi-level Dropdown - hover

Or, you can use this CSS only method for Navbar dropdowns...

.dropdown-submenu {
  position: relative;
}

.dropdown-submenu .dropdown-menu {
  top: 0;
  left: 100%;
  margin-top: -1px;
}

.navbar-nav li:hover > ul.dropdown-menu {
    display: block;
}

Bootstrap 5 Navbar Dropdown Hover Submenus (CSS only)

Bootstrap 4 (update 2018)

The dropdown-submenu has been removed in Bootstrap 3 RC. In the words of Bootstrap author Mark Otto..

"Submenus just don't have much of a place on the web right now, especially the mobile web. They will be removed with 3.0" - https://github.com/twbs/bootstrap/pull/6342

But, with a little extra CSS you can get the same functionality.

navbar submenu on hover:

.navbar-nav li:hover > ul.dropdown-menu {
    display: block;
}
.dropdown-submenu {
    position:relative;
}
.dropdown-submenu>.dropdown-menu {
    top:0;
    left:100%;
    margin-top:-6px;
}

Navbar submenu dropdown hover
Navbar submenu dropdown hover (right aligned)
Navbar submenu dropdown click (right aligned)
Navbar dropdown hover (no submenu)

Bootstrap 3

~~Here is an example that uses 3.0 RC 1: http://bootply.com/71520~~

Here is an example that uses Bootstrap 3.0.0 (final): http://bootply.com/86684

CSS

.dropdown-submenu {
    position:relative;
}
.dropdown-submenu>.dropdown-menu {
    top:0;
    left:100%;
    margin-top:-6px;
    margin-left:-1px;
    -webkit-border-radius:0 6px 6px 6px;
    -moz-border-radius:0 6px 6px 6px;
    border-radius:0 6px 6px 6px;
}
.dropdown-submenu:hover>.dropdown-menu {
    display:block;
}
.dropdown-submenu>a:after {
    display:block;
    content:" ";
    float:right;
    width:0;
    height:0;
    border-color:transparent;
    border-style:solid;
    border-width:5px 0 5px 5px;
    border-left-color:#cccccc;
    margin-top:5px;
    margin-right:-10px;
}
.dropdown-submenu:hover>a:after {
    border-left-color:#ffffff;
}
.dropdown-submenu.pull-left {
    float:none;
}
.dropdown-submenu.pull-left>.dropdown-menu {
    left:-100%;
    margin-left:10px;
    -webkit-border-radius:6px 0 6px 6px;
    -moz-border-radius:6px 0 6px 6px;
    border-radius:6px 0 6px 6px;
}

Sample Markup

<div class="navbar navbar-default navbar-fixed-top" role="navigation">
    <div class="container">
        <div class="navbar-header">
            <button type="button" class="navbar-toggle" data-toggle="collapse" data-target=".navbar-ex1-collapse">  
                <span class="sr-only">Toggle navigation</span>
                <span class="icon-bar"></span>
                <span class="icon-bar"></span>
                <span class="icon-bar"></span>
            </button>
        </div>
        <div class="collapse navbar-collapse navbar-ex1-collapse">
            <ul class="nav navbar-nav">
                <li class="menu-item dropdown">
                    <a href="#" class="dropdown-toggle" data-toggle="dropdown">Drop Down<b class="caret"></b></a>
                    <ul class="dropdown-menu">
                        <li class="menu-item dropdown dropdown-submenu">
                            <a href="#" class="dropdown-toggle" data-toggle="dropdown">Level 1</a>
                            <ul class="dropdown-menu">
                                <li class="menu-item ">
                                    <a href="#">Link 1</a>
                                </li>
                                <li class="menu-item dropdown dropdown-submenu">
                                    <a href="#" class="dropdown-toggle" data-toggle="dropdown">Level 2</a>
                                    <ul class="dropdown-menu">
                                        <li>
                                            <a href="#">Link 3</a>
                                        </li>
                                    </ul>
                                </li>
                            </ul>
                        </li>
                    </ul>
                </li>
            </ul>
        </div>
    </div>
</div>

P.S. - Example in navbar that adjusts left position: http://bootply.com/92442

Best Solution

Related Solutions

Php – How to generate a custom menu/sub-menu system using wp_get_nav_menu_items in WordPress

Quick code example on a gist

TL;DR

Complete Code explanation

Css – Bootstrap dropdown sub menu missing

Related Question