I hadn’t needed to write a custom widget before today, but I needed to have disabled options included in a <select> list. After a little research and a LOT of trial and error, this is what I came up with.<\/p>\n
from django.forms.widgets import Select, force_unicode, flatatt, escape, mark_safe, chain, conditional_escape\r\n\r\nclass SelectDisabled(Select):\r\n def __init__(self, attrs=None, choices=(), disabled=[]):\r\n super(SelectDisabled, self).__init__(attrs, choices)\r\n self.disabled = list(disabled)\r\n\r\n def render(self, name, value, attrs=None, choices=()):\r\n if value is None: value = ''\r\n final_attrs = self.build_attrs(attrs, name=name)\r\n output = [u'<select%s>' % flatatt(final_attrs)]\r\n options = self.render_options(choices, [value], self.disabled)\r\n if options:\r\n output.append(options)\r\n output.append('<\/select>')\r\n return mark_safe(u'\\n'.join(output))\r\n\r\n def render_options(self, choices, selected_choices, disabled_choices):\r\n def render_option(option_value, option_label):\r\n option_value = force_unicode(option_value)\r\n option_label = (option_value in disabled_choices) and (force_unicode(option_label) + ' - SOLD OUT') or force_unicode(option_label)\r\n selected_html = (option_value in selected_choices) and u' selected=\"selected\"' or ''\r\n disabled_html = (option_value in disabled_choices) and u' disabled=\"disabled\"' or ''\r\n return u'<option value=\"%s\"%s%s>%s<\/option>' % (\r\n escape(option_value), selected_html, disabled_html,\r\n conditional_escape(option_label))\r\n # Normalize to strings.\r\n selected_choices = set([force_unicode(v) for v in selected_choices])\r\n disabled_choices = set([force_unicode(v) for v in disabled_choices])\r\n output = []\r\n for option_value, option_label in chain(self.choices, choices):\r\n if isinstance(option_label, (list, tuple)):\r\n output.append(u'<optgroup label=\"%s\">' % escape(force_unicode(option_value)))\r\n for option in option_label:\r\n output.append(render_option(*option))\r\n output.append(u'<\/optgroup>')\r\n else:\r\n output.append(render_option(option_value, option_label))\r\n return u'\\n'.join(output)<\/pre>\nAnd here’s how I used it in the form:<\/p>\n
\r\nclass B2CRegistrationStartForm(Form): \r\n def __init__(self, disabled, *args, **kwargs):\r\n super(B2CRegistrationStartForm, self).__init__(*args, **kwargs)\r\n if disabled:\r\n self.fields['event'].widget.disabled = disabled\r\n event = ModelChoiceField(widget=SelectDisabled(),queryset=Event.b2c_web_reg.all(),empty_label=None) \r\n<\/pre>\nAnd here is the form creation in views.py:<\/p>\n
disabled = []\r\n for e in Event.b2c_sold_out.values_list('id'):\r\n disabled.append(e[0])\r\n form = B2CRegistrationStartForm( data=request.POST or None, disabled=disabled)<\/pre>\n(The list of disabled IDs needs to be in a list, not a list of tuples)<\/p>\n
It works fine, and I learned about custom widgets, but I don’t feel like I was very Object Oriented in my approach. The __init__() method uses super() well, but the other two basically replace the methods in the parent class. When I update to a newer version of Django (from the current 1.0.4), I’ll have to check this carefully and probably redo it.<\/p>\n
Anyone have suggestions on how I could better implement this feature?<\/p>\n","protected":false},"excerpt":{"rendered":"
I hadn’t needed to write a custom widget before today, but I needed to have disabled options included in a <select> list. After a little research and a LOT of trial and error, this is what I came up with. from django.forms.widgets import Select, force_unicode, flatatt, escape, mark_safe, chain, conditional_escape class SelectDisabled(Select): def __init__(self, attrs=None, … <\/p>\n