为什么我的Django表单执行两次？ [英] Why is My Django Form Executed Twice?
问题描述
第一个打印语句发生在我从表单中单击提交 2.第二个打印声明是从表单2中点击的第二个提交之后。如何使其仅打印一次？
views.py
def form1（request）：
NameFormSet = formset_factory（NameForm，formset = BaseNodeFormSet ，extra = 2，max_num = 5）
如果request.method =='POST'：
name_formset = NameFormSet（request.POST，prefix ='nameform'）
如果name_formset.is_valid（）：
data = name_formset.cleaned_data
request.session ['data'] = data
return HttpResponseRedirect（'form2 '）
else：
name_formset = NameFormSet（prefix ='nameform'）
context = {'name_formset'：name_formset}
return render（request，'nameform / form1.html'，context）
def form2（request）：
data = request.session [ 'data']
print（'Form from Form 2'）＃< ====这个语句在控制台中打印两次
CheckBoxFormSet = formset_factory（CheckBox，extra = 2，max_num = 5）
如果request.method =='POST'：
checkbox_formset = CheckBoxFormSet（request.POST，prefix ='checkbox'）
如果checkbox_formset.is_valid（）：
for i，form in enumerate（checkbox_formset.cleaned_data）：
data [i] .update（form）＃加入原始数据的清理数据
del request.session ['data']
context = {'data'：data}
return render（request，'nameform / success.html'，context）
checkbox_formset = CheckBoxFormSet（prefix ='checkbox'）
context = {'checkb ox_formset'：checkbox_formset，'data'：data}
return render（request，'nameform / form2'，context）
更新1：
print语句实际上是一个后端方法，用于处理从表单1获取的数据，并以表单2显示。现在将导致该方法处理信息两次。我没有问题或错误这样做，但没有必要。
例如：
def form2（request）：
data = request.session ['data']
n，errors = getInfo（data）＃< ====这个语句在控制台
中执行两次，如果request.method ='POST'：
....
if checkbox_formset.is_valid（）：
for i，form in enumerate（checkbox_formset。 clean_data）：
data [i] .update（form）＃使用原始数据加入清理的数据
n.process_new_data（数据，错误）
del request.session ['data ']
context = {'data'：data，'errors'：error}
return render（request，'nameform / success.html'，context）
else：
checkbox_formset = CheckBoxFormset（prefix ='checkbox'）
context = {'data'：data，'errors'：error}
return ren （请求，'nameform / form2.html'，上下文）
更新2 ：
由于我的解释有点长，请允许我在这里填写Ale问题。
是的，我完全明白为什么它被处理了两次。要简单地回答你的问题，将getInfo放在'POST'中会给我一个上下文，因为上下文错误字典在第一个重定向中不存在，所以没有绑定错误。
context = {'data'：data，'errors'：errors}
我会更新我的帖子，以便我可以解释为什么我不能使用你的方法。 GetInfo从form1获取数据，处理它，并将其传递给表单2进行显示。我可以在form1中执行所有操作，但是我必须在form2中重做它，因为form2将不知道'n'或'errors'是不通过会话传递的。
form2视图运行两次，一次为一个重定向从form1创建表单并渲染模板，如果request.method =='POST'部分作为这个时间周围的请求，缺少是一个GET。
当您将form2提交回相同的视图方法时，它会打印您再次指示的行，此时if块中的代码将执行，因为请求是POST
关键是这一行重定向到form2视图：
return HttpResponseRedirect（'form2'）
Can someone explain to me why form 2 executed twice? In another word, I would see 2 print statements, "Hello from form 2," in the console.
The first print statement occurred after I clicked "Submit" from form 1. Second print statement comes after the second "Submit" I clicked from form 2. How do I make it to only print once?
views.py
def form1 (request):
NameFormSet = formset_factory (NameForm, formset = BaseNodeFormSet, extra = 2, max_num = 5)
if request.method == 'POST':
name_formset = NameFormSet (request.POST, prefix = 'nameform')
if name_formset.is_valid ():
data = name_formset.cleaned_data
request.session ['data'] = data
return HttpResponseRedirect ('form2')
else:
name_formset = NameFormSet (prefix = 'nameform')
context = {'name_formset': name_formset}
return render (request, 'nameform/form1.html', context)
def form2 (request):
data = request.session ['data']
print ('Hello from form 2') # <==== This statement printed twice in the console
CheckBoxFormSet = formset_factory (CheckBox, extra = 2, max_num = 5)
if request.method == 'POST':
checkbox_formset = CheckBoxFormSet (request.POST, prefix = 'checkbox')
if checkbox_formset.is_valid ():
for i, form in enumerate (checkbox_formset.cleaned_data):
data [i].update (form) # Join cleaned data with original data
del request.session ['data']
context = {'data': data}
return render (request, 'nameform/success.html', context)
checkbox_formset = CheckBoxFormSet (prefix = 'checkbox')
context = {'checkbox_formset': checkbox_formset, 'data': data}
return render (request, 'nameform/form2', context)
Update 1: The "print" statement is actually a backend method that processes the data obtained from form 1 and display it in form 2. Leaving where it is now would cause that method to process the information twice. I have no issue or error doing it this way but it's unnecessary.
For example:
def form2 (request):
data = request.session ['data']
n, errors = getInfo (data) # <==== This statement performed twice in the console
if request.method = 'POST':
....
if checkbox_formset.is_valid ():
for i, form in enumerate (checkbox_formset.cleaned_data):
data [i].update (form) # Join cleaned data with original data
n.process_new_data (data, errors)
del request.session ['data']
context = {'data': data, 'errors': error}
return render (request, 'nameform/success.html', context)
else:
checkbox_formset = CheckBoxFormset (prefix = 'checkbox')
context = {'data': data, 'errors': error}
return render (request, 'nameform/form2.html', context)
Update 2: Since my explanation is a little long, allow me address Ale question here.
Yes, I fully understand why it processed twice. To briefly answer your question, putting getInfo inside 'POST' will give me a context, unbound error because of the context "errors" dictionary doesn't exist in the first redirect.
context = {'data': data, 'errors': errors}
I'd to update my post so that I can explain why I can't use your method. GetInfo takes the data from form1, processes it, and passes it on to form 2 to display. I could do all that in form1 but then I would have to redo it in form2 because form2 will not know what 'n' or 'errors' is without passing it through sessions. I'm just trying to see if there's a better way to do this.
The form2 view is run twice, once as a redirect from form1 which creates the form and renders the template, missing the if request.method == 'POST' part as this time around the request is a 'GET'.
When you submit form2 back to the same view method it prints the line you indicate again, this time the code in the if block executes as the request is a 'POST'.
The key is this line that redirects to the form2 view:
return HttpResponseRedirect ('form2')
这篇关于为什么我的Django表单执行两次？的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
