Django将ModelForm显示为html表单

Question

I am trying to do a very simple django webpage where a user fills 2 fields of a form with two numbers, submits them and gets a result at the third field. I am using ModelForms.

For the moment I am only interested in the first part, where the user navigates to the url and is prompted a page with the empty form. I do the following, but the page I see at my browser has no form, and only the submit button. I don't know if that's because the ModelForm I try to embed in the html code is still empty, but I tried to give it default values and it still didn't work. Any help will be very appreciated! :)

urls.py:

urlpatterns = patterns('',
    url(r'^calculator/', views.calculate)
)

models.py:

class Calc(models.Model):
    field1 = forms.CharField()
    field2 = forms.CharField()
    field3 = forms.CharField()   

class CalcForm(ModelForm):
    class Meta:
        model = Calc

views.py:

def calculate(request):
    c = CalcForm()
    if request.method == 'POST':
        #do the math
        #return ...
    else:
        return render_to_response('home.html', {'calculator': c}) 

home.html:

<form action="/calculator/" method="post"> 
<table>
{{ calculator }}<!--I also tried .as_p, .as_ul...-->
</table>
<input type="submit" value="Submit" />
</form>

Answer 1

您的模型应使用models.CharField，而不是form.CharField。

Answer 2

change the following:

class Calc(models.Model):
    field1 = forms.CharField()
    field2 = forms.CharField()
    field3 = forms.CharField()

to

class Calc(models.Model):
    field1 = models.CharField(max_length=10)
    field2 = models.CharField(max_length=10)
    field3 = models.CharField(max_length=10)

Did you ever syncdb with the above code? Because if you would've, it must have thrown an error. This makes me think if your db has the correct tables or not. Make sure you syncdb after the above change.

Also, you should always check if an instance exist, This will also help you troubleshoot that if the object was correctly passed or not:

{% if calculator %}
    <h3>Calculation Form</h3>
    <form action="/calculator/" method="post"> 
        <table>
            {{ calculator }}
        </table>
        <input type="submit" value="Submit" />
    </form>
{% endif %}