验证失败时的Django表单字段初始值

Question

提交表单但验证失败后，如何设置字段元素的值？例如

if form.is_valid():
    form.save()
else:
    form.data['my_field'] = 'some different data'

我真的不想把它放在 View 中，而是希望将它作为表单类的一部分。

谢谢

Answer 1

documentation说:

If you have a bound Form instance and want to change the data somehow, or if you want to bind an unbound Form instance to some data, create another Form instance. There is no way to change data in a Form instance. Once a Form instance has been created, you should consider its data immutable, whether it has data or not.

我真的不敢相信你的代码有效。但是没问题。根据文档，我会这样做:

if request.method == 'POST':
    data = request.POST.copy()
    form = MyForm(data)
    if form.is_valid(): 
        form.save() 
    else: 
        data['myField'] = 'some different data'
        form = MyForm(initial=data)