Folks,
I would appreciate some help figuring out how to create a
templated form scenario. The quick form of the question is
either:
How do I iterate over two form field list simultaneously
in my template using {% for f in form %}, sort of like
{% for f,g in form1,form2 %}?
or
How do I iterate over a list of strings and use that to
select form fields in my template?
Gory details of and failed attempts follow...
I have a dynamically created form, attr_form, that derives
its fields from a query and adds pairs of fields to the form
roughly like this in my forms.py:
def create_attribute_form():
class AttrForm(forms.Form):
for every DB Attribute field, attr, on something:
name = attr.name # Eg: "Volume"
units = "%s-units" % name # Eg: "Volume-units"
self.fields[name] = forms.FloatField() # Eg, "17.0"
self.fields[units] = forms.ModelChoiceField(...) # Eg, "Liters"
In my view, I trump up this form and hand it to my template in
a context as "attr_form". I know this form gets to my template
correctly because I can simply place {{ attr_form.as_p }} in it
and all the fields are present. They are just not how I want
them arranged.
Specifically, I want to arrange them into a table like this:
Attribute | Value | Units
-----------------|-------|---------
Temperature | 70 | C
Volume | 17 | Liters
Which means I need to iterate over "Volume" and "Temperature"
attribute names, and locate the "Volume" field and then the
"Volume-units" field of my form in order to form one row of
the table before going on to the next.
If I just iterate over the attr_form straight up, I will see
all the attributes, of course.
So I kind of want to do this (not working) in my template:
with:
{{ attr_list }} == [ "Volume", "Temperature" ]
{{ attr_form }} == The form instance with pairs of fields in it
<table>
<th>.....</th>
{% for attr in attr_list %}
<tr>
<td>{{attr}}</td>
<td>{{attr_form.fields.$attr.}}</td>
<td>{{attr_form.fields."$attr"-"units".}}</td>
</tr>
{% endfor %}
</table>
Naturally that $attr and constructing that $attr-"units" thing
is totaly bogus. But even if I passed in a list of tuples
with ("Volume", "Volume-units") in it and looped over that,
I still can't use those for-loop-variables to index into the
form's fields[] to get and print the fields!
So another approach I tried was this: In my view, create a list of
triplets with:
("Volume", <Volume's float form field>, <Volume-units' form field>)
and pass that into the template as "attr_trio":
<table>
<th>.....</th>
{% for a,v,u in attr_trio %}
<tr>
<td>{{a}}</td>
<td>{{v}}</td>
<td>{{u}}</td>
</tr>
{% endfor %}
</table>
This *almost* works, but what I get is a table like:
Volume <django.forms.fields.FloatField <django....ModelChoiceField
object at 0x2768590> object at 0x2768910>
Temperature <django.forms.fields.FloatField <django....ModelChoiceField
object at 0x2768790> object at 0x2768050>
That looks like the v and u parts are either un-instantiated,
or being processed differently, or un-bound, or *something*...
As another approach I've explored unsuccessfully so far,
I've tried to create two forms: one with the Attribute fields
and another with the corresponding Units fields. I can pass
both those into the template, but now I need a way to iterate
over the attr_form and units_form simultaneously so that I
can grab a "Volume" and a "Volume-units" field for one row.
I have the itertable list of ["Volume", "Temperature", ...] available,
but I don't know how to use that iteration variable name to select
the form field from the two forms:
with:
{{ attr_list }} == [ "Volume", "Temperature" ]
{{ attr_form }} == The form instance with just Attribute fields
{{ units_form }} == The form instance with corresponding Units fields
<table>
<th>.....</th>
{% for a in attr_list %}
<tr>
<td>{{a}}</td>
<td>{{attr_form.a}}</td>
<td>{{units_form.a}}</td>
</tr>
{% endfor %}
</table>
Even that glosses over the problem of having a form with two
fields labeled with the same name. I'd really have to loop over
a tuple of ("Volume", "Volume-units") like:
{% for a,u in attrunit_list %}
...
<td>{{a}}</td>
<td>{{attr_form.a}}</td>
<td>{{units_form.u}}</td>
But none of that works either.
OK. Any chance someone can point out the forehead-slapping
obvious solution for me? Or point me in the right direction?
Should I give up on doing this in the template and somehow
render the whole form into a string in the view and pass that
into the template to slap it down? Does that violate some
large abstraction separation? :-)
Thanks,
jdl
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