Django Forms if not valid show form with error message

Question

In Django forms  it can check whether the form is valid  if form is valid         return HttpResponseRedirect   thanks     But I m missing what to do if it isn t valid  How do I return the form with the error messages  I m not seeing the  quot else quot  in any of the examples

User · Answer

You can put simply a flag variable  in this case is successed   def preorder view request  pk  template name  preorders preorder form html        is successed 0     formset   PreorderHasProductsForm request POST      client  get object or 404 Client  pk pk      if request method   POST            populate the form with data from the request          formset   PreorderHasProductsForm request POST          if formset is valid                is successed 1             preorder date formset cleaned data  preorder date               product formset cleaned data  preorder has products               return render request  template name    preorder date  preorder date  product  product  is successed  is successed  formset  formset          return render request  template name    object  client  formset  formset     afterwards in your template you can just put the code below    if is successed    1     lt h1 gt   preorder date   lt  h1 gt   lt h2 gt    product   lt  h2 gt    endif

User · Answer

UPDATE  Added a more detailed description of the formset errors     Form errors combines all field and non field errors  Therefore you can simplify the html to this   template         load form tags            if form errors         lt div class  alert alert-danger alert-dismissible col-12 mx-1  role  alert  gt           lt div id  form errors  gt                 for key  value in form errors items                     lt span class  fieldWrapper  gt                         key       value                     lt  span gt                 endfor             lt  div gt           lt button type  button  class  close  data-dismiss  alert  aria-label  Close  gt               lt span aria-hidden  true  gt  amp times  lt  span gt           lt  button gt       lt  div gt         endif      If you want to generalise it you can create a list errors html which you include in every form template  It handles form and formset errors          if form errors         lt div class  alert alert-danger alert-dismissible col-12 mx-1  role  alert  gt           lt div id  form errors  gt                  for key  value in form errors items                     lt span class  fieldWrapper  gt                         key       value                     lt  span gt                 endfor             lt  div gt           lt button type  button  class  close  data-dismiss  alert  aria-label  Close  gt               lt span aria-hidden  true  gt  amp times  lt  span gt           lt  button gt       lt  div gt         elif formset total error count         lt div class  alert alert-danger alert-dismissible col-12 mx-1  role  alert  gt           lt div id  form errors  gt                 if formset non form errors                       formset non form errors                   endif                   for form in formset forms                       if form errors                        Form number    forloop counter                          lt ul class  errorlist  gt                         for key  error in form errors items                             lt li gt   form fields get label key                                lt ul class  errorlist  gt                                   lt li gt   error   lt  li gt                               lt  ul gt                           lt  li gt                         endfor                         lt  ul gt                     endif                   endfor              lt  div gt       lt  div gt          endif      form tags py  from django import template  register   template Library     def get label a dict  key       return getattr a dict get key    label    No label     register filter  get label   get label     One caveat  In contrast to forms Formset errors does not include non field errors

User · Answer

This answer is correct but has a problem  fields not defined  If you have more then one field  you can not recognize which one has error  with this change you can display field name     if form errors           for field in form               for error in field errors                 lt div class  quot alert alert-danger quot  gt                   lt strong gt    field label    lt  strong gt  lt span gt    error escape    lt  strong gt               lt  div gt             endfor           endfor           for error in form non field errors             lt div class  quot alert alert-danger quot  gt               lt strong gt    error escape    lt  strong gt           lt  div gt         endfor       endif

User · Answer

AamirAdnan s answer missing field label  the other way to show the errors in few lines     if form errors         lt  -- Error messaging -- gt       lt div id  quot errors quot  gt           lt div class  quot inner quot  gt               lt p gt There were some errors in the information you entered  Please correct the following  lt  p gt               lt ul gt                     for field in form                           if field errors    lt li gt    field label        field errors striptags    lt  li gt    endif                       endfor                 lt  ul gt           lt  div gt       lt  div gt       lt  --  Error messaging -- gt     endif

User · Answer

def some view request       if request method     POST           form   SomeForm request POST          if form is valid                return HttpResponseRedirect   thanks        else          form   SomeForm       return render request   some form html     form   form

User · Answer

views py from django contrib import messages   def view name request       if request method     POST           form   form class request POST          if form is valid                return HttpResponseRedirect   thanks            else              messages error request   quot Error quot   return render request   page html     form  form class      If you want to show the errors of the form other than that not valid just put   form as p   like what I did below page html  lt html gt       lt head gt           lt script gt                 if messages                       for message in messages                        alert    message                        endfor                   endif             lt  script gt       lt  head gt       lt body gt            form as p        lt  body gt   lt  html gt

User · Answer

simply you can do like this because when you initialized the form in contains form data and invalid data as well   def some func request       form   MyForm request POST      if form is valid               other stuff     return render request template name   form  form     if will raise the error in the template if have any but the form data will still remain as    error demo here

User · Answer

If you render the same view when the form is not valid then in template you can access the form errors using form errors      if form errors           for field in form               for error in field errors                 lt div class  alert alert-danger  gt                   lt strong gt    error escape    lt  strong gt               lt  div gt             endfor           endfor           for error in form non field errors             lt div class  alert alert-danger  gt               lt strong gt    error escape    lt  strong gt           lt  div gt         endfor       endif      An example   def myView request       form   myForm request POST or None  request FILES or None      if request method     POST           if form is valid                return HttpResponseRedirect   thanks        return render request   my template html     form   form

[django] Django Forms: if not valid, show form with error message

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