在Django表单中,我如何使字段只读(或禁用)?

当使用表单创建新条目时,应该启用所有字段——但当记录处于更新模式时,某些字段需要为只读。

例如,当创建一个新的Item模型时,所有字段都必须是可编辑的,但是在更新记录时,是否有一种方法禁用sku字段,使其可见,但不能编辑?

class Item(models.Model):
    sku = models.CharField(max_length=50)
    description = models.CharField(max_length=200)
    added_by = models.ForeignKey(User)


class ItemForm(ModelForm):
    class Meta:
        model = Item
        exclude = ('added_by')

def new_item_view(request):
    if request.method == 'POST':
        form = ItemForm(request.POST)
        # Validate and save
    else:
            form = ItemForm()
    # Render the view

ItemForm类可以重用吗?ItemForm或Item模型类需要做哪些更改?我是否需要编写另一个类“ItemUpdateForm”来更新项目?

def update_item_view(request):
    if request.method == 'POST':
        form = ItemUpdateForm(request.POST)
        # Validate and save
    else:
        form = ItemUpdateForm()

当前回答

对于Django 1.2+,你可以像这样重写字段:

sku = forms.CharField(widget = forms.TextInput(attrs={'readonly':'readonly'}))

其他回答

另外两种(类似的)方法和一个通用的例子:

1)第一种方法-删除save()方法中的字段,例如(未测试;)):

def save(self, *args, **kwargs):
    for fname in self.readonly_fields:
        if fname in self.cleaned_data:
            del self.cleaned_data[fname]
    return super(<form-name>, self).save(*args,**kwargs)

2)第二种方法-在clean方法中将字段重置为初始值:

def clean_<fieldname>(self):
    return self.initial[<fieldname>] # or getattr(self.instance, fieldname)

基于第二种方法,我将其概括为:

from functools                 import partial

class <Form-name>(...):

    def __init__(self, ...):
        ...
        super(<Form-name>, self).__init__(*args, **kwargs)
        ...
        for i, (fname, field) in enumerate(self.fields.iteritems()):
            if fname in self.readonly_fields:
                field.widget.attrs['readonly'] = "readonly"
                field.required = False
                # set clean method to reset value back
                clean_method_name = "clean_%s" % fname
                assert clean_method_name not in dir(self)
                setattr(self, clean_method_name, partial(self._clean_for_readonly_field, fname=fname))

    def _clean_for_readonly_field(self, fname):
        """ will reset value to initial - nothing will be changed 
            needs to be added dynamically - partial, see init_fields
        """
        return self.initial[fname] # or getattr(self.instance, fieldname)

我也遇到过类似的问题。 看起来我可以通过在ModelAdmin类中定义get_readonly_fields方法来解决这个问题。

就像这样:

# In the admin.py file

class ItemAdmin(admin.ModelAdmin):

    def get_readonly_display(self, request, obj=None):
        if obj:
            return ['sku']
        else:
            return []

好的事情是,当你添加一个新的项目时,obj将是None,或者当你改变一个现有的项目时,它将是正在编辑的对象。

Get_readonly_display记录在这里。

为了使ForeignKey字段能够正常工作,需要做一些更改。首先,SELECT HTML标记没有readonly属性。我们需要使用disabled="disabled"来代替。但是,浏览器不会为该字段返回任何表单数据。因此,我们需要将该字段设置为非必需,以便该字段能够正确验证。然后,我们需要将值重置为以前的值,这样它就不会被设置为空白。

所以对于外键,你需要做如下的事情:

class ItemForm(ModelForm):

    def __init__(self, *args, **kwargs):
        super(ItemForm, self).__init__(*args, **kwargs)
        instance = getattr(self, 'instance', None)
        if instance and instance.id:
            self.fields['sku'].required = False
            self.fields['sku'].widget.attrs['disabled'] = 'disabled'

    def clean_sku(self):
        # As shown in the above answer.
        instance = getattr(self, 'instance', None)
        if instance:
            return instance.sku
        else:
            return self.cleaned_data.get('sku', None)

通过这种方式,浏览器不会让用户更改字段,并且总是POST,因为它是空的。然后重写clean方法,将字段的值设置为实例中的原始值。

你可以这样做:

检查请求是否更新或保存一个新对象。 如果请求更新,则禁用字段sku。 如果请求是添加一个新对象,那么您必须在不禁用字段sku的情况下呈现表单。

这里有一个如何这样做的例子。

class Item(models.Model):
    sku = models.CharField(max_length=50)
    description = models.CharField(max_length=200)
    added_by = models.ForeignKey(User)


class ItemForm(ModelForm):
    def disable_sku_field(self):
        elf.fields['sku'].widget.attrs['readonly'] = True

    class Meta:
        model = Item
        exclude = ('added_by')

def new_item_view(request):
    if request.method == 'POST':
        form = ItemForm(request.POST)
        # Just create an object or instance of the form.
        # Validate and save
    else:
            form = ItemForm()
    # Render the view

def update_item_view(request):
    if request.method == 'POST':
        form = ItemForm(request.POST)
        # Just create an object or instance of the form.
        # Validate and save
    else:
        form = ItemForm()
        form.disable_sku_field() # call the method that will disable field.

    # Render the view with the form that will have the `sku` field disabled on it.

如果您需要多个只读字段。您可以使用下面给出的任何方法

方法1

class ItemForm(ModelForm):
    readonly = ('sku',)

    def __init__(self, *arg, **kwrg):
        super(ItemForm, self).__init__(*arg, **kwrg)
        for x in self.readonly:
            self.fields[x].widget.attrs['disabled'] = 'disabled'

    def clean(self):
        data = super(ItemForm, self).clean()
        for x in self.readonly:
            data[x] = getattr(self.instance, x)
        return data

方法2

继承的方法

class AdvancedModelForm(ModelForm):


    def __init__(self, *arg, **kwrg):
        super(AdvancedModelForm, self).__init__(*arg, **kwrg)
        if hasattr(self, 'readonly'):
            for x in self.readonly:
                self.fields[x].widget.attrs['disabled'] = 'disabled'

    def clean(self):
        data = super(AdvancedModelForm, self).clean()
        if hasattr(self, 'readonly'):
            for x in self.readonly:
                data[x] = getattr(self.instance, x)
        return data


class ItemForm(AdvancedModelForm):
    readonly = ('sku',)