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This document contains details about the template tags and filters Django MPTT provides for working with trees of model instances.
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The mptt.templatetags.mptt_tags module defines template tags and filters for working with trees of model instances.
To use these, you must add mptt to your project's INSTALLED_APPS setting, then you can load the tag module in your templates using {% load mptt_tags %}
Populates a template variable with a QuerySet containing the full tree for a given model.
Usage:
{% full_tree_for_model [model] as [varname] %}
The model is specified in [appname].[modelname] format.
Example:
{% full_tree_for_model tests.Genre as genres %}
Populates a template variable with the drilldown tree for a given node, optionally counting the number of items associated with its children.
A drilldown tree consists of a node's ancestors, itself and its immediate children. For example, a drilldown tree for a book category "Personal Finance" might look something like:
Books
Business, Finance & Law
Personal Finance
Budgeting (220)
Financial Planning (670)
Usage:
{% drilldown_tree_for_node [node] as [varname] %}
Extended usage:
{% drilldown_tree_for_node [node] as [varname] count [foreign_key] in [count_attr] %}
{% drilldown_tree_for_node [node] as [varname] cumulative count [foreign_key] in [count_attr] %}
The foreign key is specified in [appname].[modelname].[fieldname] format, where fieldname is the name of a field in the specified model which relates it to the given node's model.
When this form is used, a count_attr attribute on each child of the given node in the drilldown tree will contain a count of the number of items associated with it through the given foreign key.
If cumulative is also specified, this count will be for items related to the child node and all of its descendants.
Examples:
{% drilldown_tree_for_node genre as drilldown %}
{% drilldown_tree_for_node genre as drilldown count tests.Game.genre in game_count %}
{% drilldown_tree_for_node genre as drilldown cumulative count tests.Game.genre in game_count %}
See template tag examples for an example of how to render a drilldown tree as a nested list.
Given a list of tree items, iterates over the list, generating two-tuples of the current tree item and a dict containing information about the tree structure around the item, with the following keys:
- 'new_level'
- True if the current item is the start of a new level in the tree, False otherwise.
- 'closed_levels'
- A list of levels which end after the current item. This will be an empty list if the next item's level is the same as or greater than the level of the current item.
An optional argument can be provided to specify extra details about the structure which should appear in the dict. This should be a comma-separated list of feature names. The valid feature names are:
- ancestors
Adds a list of unicode representations of the ancestors of the current node, in descending order (root node first, immediate parent last), under the key 'ancestors'.
For example: given the sample tree below, the contents of the list which would be available under the 'ancestors' key are given on the right:
Books -> [] Sci-fi -> [u'Books'] Dystopian Futures -> [u'Books', u'Sci-fi']
Using this filter with unpacking in a {% for %} tag, you should have enough information about the tree structure to create a hierarchical representation of the tree.
Example:
{% for genre,structure in genres|tree_info %}
{% if structure.new_level %}<ul><li>{% else %}</li><li>{% endif %}
{{ genre.name }}
{% for level in structure.closed_levels %}</li></ul>{% endfor %}
{% endfor %}
Creates a tree path represented by a list of items by joining the items with a separator, which can be provided as an optional argument, defaulting to ' :: '.
Each path item will be coerced to unicode, so a list of model instances may be given if required.
Example:
{{ some_list|tree_path }}
{{ some_node.get_ancestors|tree_path:" > " }}
An example of the drilldown_tree_for_node tag and the tree_info filter being used together to render a drilldown menu for a node, with cumulative counts of related items being displayed for the node's children:
{% drilldown_tree_for_node genre as drilldown cumulative count tests.Game.genre in game_count %}
{% for node,structure in drilldown|tree_info %}
{% if structure.new_level %}<ul><li>{% else %}</li><li>{% endif %}
{% ifequal node genre %}
<strong>{{ node.name }}</strong>
{% else %}
<a href="{{ node.get_absolute_url }}">{{ node.name }}</a>
{% ifequal node.parent_id genre.pk %}({{ node.game_count }}){% endifequal %}
{% endifequal %}
{% for level in structure.closed_levels %}</li></ul>{% endfor %}
{% endfor %}
An example of the``tree_info`` (with its optional argument) and tree_path filters being used together to create a multiple select which doesn't contain root nodes and displays the full path to each option's node:
<select name="classifiers" multiple="multiple" size="10">
{% for node,structure in classifiers|tree_info:"ancestors" %}
{% if node.is_child_node %}
<option value="{{ node.pk }}">
{{ structure.ancestors|tree_path }} :: {{ node }}
</option>
{% endif %}
{% endfor %}
</select>