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--- wiki2:python:django:forms [2018/11/10 17:47]
alfred
+++ wiki2:python:django:forms [2020/05/09 09:25] (actual)
@@ Línea 47: / Línea 47: @@
 </code>
 <code>
-# In form_snippet.html:
+<form method="post" novalidate>
-{% for field in form %}
+  {% csrf_token %}
-    <div class="fieldWrapper">
-        {{ field.errors }}
+  {{ form.non_field_errors }}
-        {{ field.label_tag }} {{ field }}
-    </div>
+  {% for hidden_field in form.hidden_fields %}
+    {{ hidden_field.errors }}
+    {{ hidden_field }}
+  {% endfor %}
+  <table border="1">
+    {% for field in form.visible_fields %}
+      <tr>
+        <th>{{ field.label_tag }}</th>
+        <td>
+          {{ field.errors }}
+          {{ field }}
+          {{ field.help_text }}
+        </td>
+      </tr>
+    {% endfor %}
+  </table>
+  <button type="submit">Submit</button>
+</form>
+</code>
+==== How does it work? ====
+When we write ''<nowiki>{{ form }}</nowiki>'' in a template, it’s actually accessing the ''<nowiki>__str__</nowiki>'' method from the BaseForm class. We can use other three methods to render it (as table, as p, as ul tags): as_table(), as_ul(), as_p().
+The as_table() and as_ul() methods do not create the <table> and the <ul> tags, so we have to add it by ourselves.
+<code>
+<form method="post" novalidate>
+  {% csrf_token %}
+  <table border="1">
+    {{ form }}
+  </table>
+  <button type="submit">Submit</button>
+</form>
+</code>
+==== The form definition ====
+<code python>
+class ColorfulContactForm(forms.Form):
+    name = forms.CharField(
+        max_length=30,
+        widget=forms.TextInput(
+            attrs={
+                'style': 'border-color: blue;',
+                'placeholder': 'Write your name here'
+            }
+        )
+    )
+    email = forms.EmailField(
+        max_length=254,
+        widget=forms.EmailInput(attrs={'style': 'border-color: green;'})
+    )
+    message = forms.CharField(
+        max_length=2000,
+        widget=forms.Textarea(attrs={'style': 'border-color: orange;'}),
+        help_text='Write here your message!'
+    )
+</code>
+==== The validation process... ====
+Converts all the data to proper values in ''cleaned_data'' if they are, for sure, valid. An example of a Boolean field:
+<code python>
+class MyForm(forms.Form):
+    has_code = forms.BooleanField(widget= forms.CheckboxInput())
+def my_form_view(request):
+    if request.method == 'POST':
+        my_form = MyForm(request.POST)
+        if my_form.is_valid():
+            # my_form.cleaned_data['has_code'] is now a bool
+</code>
+===== Gotchas =====
+<code python>
+unique_together = ('accounting_year', 'number',)
+</code>
+===== Widgets =====
+You can define widgets on for the fields on the same form:
+<code>
+class PurchaseOrderForm(forms.ModelForm):
+    class Meta:
+        model = PurchaseOrder
+        fields = '__all__'
+        widgets = {
+            'bill_price': EuroWidget(),
+            'total_amount': EuroWidget(),
+        }
+</code>
+==== Add a widget to a field ====
+<code>
+city = forms.CharField(widget=forms.TextInput(attrs={'autocomplete':'off'}))
+</code>
+También lo puedes añadir en el meta:
+<code>
+'widgets': {'city': forms.TextInput}
+</code>
+===== Fields =====
+==== Choice ====
+=== From DB ===
+IF you are saving cities into the database, you can use ModelChoiceField:
+<code>
+class SelectCityForm(forms.Form):
+    cities = forms.ModelChoiceField(queryset=City.objects.all())
+</code>
+==== Create your own field ====
+You need the field and the widget:
+<code python>
+class SelectMultipleChecks(forms.Widget):
+    template_name = 'widgets/multiple_checks.html'
+    def __init__(self, *args, choices=(), defaults=(), **kwargs):
+        super().__init__(*args, **kwargs)
+        self.choices = choices
+    def get_context(self, name, value, attrs):
+        context = super().get_context(name, value, attrs)
+        context['choices'] = self.choices
+        return context
+class SelectMultipleChecksField(forms.Field):
+    widget = SelectMultipleChecks
+    def __init__(self, *args, choices=(), defaults=(), **kwargs):
+        super().__init__(*args, **kwargs)
+        self.choices = choices
+    def _get_choices(self):
+        return self._choices
+    def _set_choices(self, value):
+        if callable(value):
+            value = CallableChoiceIterator(value)
+        else:
+            value = list(value)
+        self._choices = self.widget.choices = value
+    choices = property(_get_choices, _set_choices)
+    def to_python(self, value):
+        import json
+        values = json.loads(value)
+        i_values = [int(v) for v in values]
+        return [choice for choice in self._choices if choice.pk in i_values]
+    def validate(self, value):
+        assert len(value) > 0
+    def valid_value(self, value):
+        return value
+</code>
+With this we can have the template ''widgets/multiple_checks.html'':
+<code html>
+<div style="display: flex; justify-content: space-around;">
+    <input type="hidden" id="{{ widget.attrs.id }}" value="[{{ selected|join:"," }}]">
+{% for choice in choices %}
+    <div><input
+            type="checkbox" {% if choice.pk in selected %}checked{% endif %}
+            name="{{widget.attrs.id}}_check"
+            data-id="{{choice.pk}}"
+    > {{ choice }}</div>
 {% endfor %}
+</div>
+</code>
+=== Set rendered properties ===
+You can set properties to render like this:
+<code>
+city = forms.CharField(widget=forms.TextInput(attrs={'autocomplete':'off'}))
 </code>

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