这篇文章将为大家详细讲解有关django中怎么利用 forms实现错误处理，文章内容质量较高，因此小编分享给大家做个参考，希望大家阅读完这篇文章后对相关知识有一定的了解。

成都创新互联公司主要从事网页设计、PC网站建设（电脑版网站建设）、wap网站建设（手机版网站建设）、成都响应式网站建设公司、程序开发、网站优化、微网站、重庆小程序开发等，凭借多年来在互联网的打拼，我们在互联网网站建设行业积累了丰富的网站制作、成都做网站、网站设计、网络营销经验，集策划、开发、设计、营销、管理等多方位专业化运作于一体。

一个form实例.

Form.errors

返回一个ErrorDict实例,包含当前表单所有的错误,可以在is_valid之前调用

Form.has_error(field, code=None)

返回指定field是否有错误

Form.add_error(field, error)

向指定field添加一个错误

Form.non_field_errors()

不属于field的错误,如数据库中有复合主键重复等.

#部分源码

@property
def errors(self):
    "Returns an ErrorDict for the data provided for the form"
    if self._errors is None:
        self.full_clean()
    return self._errors

@html_safe
@python_2_unicode_compatible
class ErrorDict(dict):
    """
    A collection of errors that knows how to display itself in various formats.

    The dictionary keys are the field names, and the values are the errors.
    """
    def as_data(self):
        return {f: e.as_data() for f, e in self.items()}

    def as_json(self, escape_html=False):
        return json.dumps({f: e.get_json_data(escape_html) for f, e in self.items()})

    def as_ul(self):
        if not self:
            return ''
        return format_html(
            '{}',
            format_html_join('', '
{}{}
', ((k, force_text(v)) for k, v in self.items()))
        )

    def as_text(self):
        output = []
        for field, errors in self.items():
            output.append('* %s' % field)
            output.append('\n'.join('  * %s' % e for e in errors))
        return '\n'.join(output)

    def __str__(self):
        return self.as_ul()

#官方文档

• Form.errors

Access the errors attribute to get a dictionary of error messages:

>>> f.errors{'sender': ['Enter a valid email address.'], 'subject': ['This field is required.']}

In this dictionary, the keys are the field names, and the values are lists of Unicode strings representing the error messages. The error messages are stored in lists because a field can have multiple error messages.

You can access errors without having to call is_valid() first. The form’s data will be validated the first time either you callis_valid() or access errors.

The validation routines will only get called once, regardless of how many times you access errors or call is_valid(). This means that if validation has side effects, those side effects will only be triggered once.

• Form.errors.as_data()

Returns a dict that maps fields to their original ValidationError instances.

>>> f.errors.as_data(){'sender': [ValidationError(['Enter a valid email address.'])],'subject': [ValidationError(['This field is required.'])]}

Use this method anytime you need to identify an error by its code. This enables things like rewriting the error’s message or writing custom logic in a view when a given error is present. It can also be used to serialize the errors in a custom format (e.g. XML); for instance,as_json() relies on as_data().

The need for the as_data() method is due to backwards compatibility. Previously ValidationError instances were lost as soon as their rendered error messages were added to the Form.errors dictionary. Ideally Form.errors would have stored ValidationErrorinstances and methods with an as_ prefix could render them, but it had to be done the other way around in order not to break code that expects rendered error messages in Form.errors.

• Form.errors.as_json(escape_html=False)

Returns the errors serialized as JSON.

>>> f.errors.as_json(){"sender": [{"message": "Enter a valid email address.", "code": "invalid"}],"subject": [{"message": "This field is required.", "code": "required"}]}

By default, as_json() does not escape its output. If you are using it for something like AJAX requests to a form view where the client interprets the response and inserts errors into the page, you’ll want to be sure to escape the results on the client-side to avoid the possibility of a cross-site scripting attack. It’s trivial to do so using a JavaScript library like jQuery - simply use $(el).text(errorText) rather than.html().

If for some reason you don’t want to use client-side escaping, you can also set escape_html=True and error messages will be escaped so you can use them directly in HTML.

• Form.add_error(field, error)

This method allows adding errors to specific fields from within the Form.clean() method, or from outside the form altogether; for instance from a view.

The field argument is the name of the field to which the errors should be added. If its value is None the error will be treated as a non-field error as returned by Form.non_field_errors().

The error argument can be a simple string, or preferably an instance of ValidationError. See Raising ValidationError for best practices when defining form errors.

Note that Form.add_error() automatically removes the relevant field from cleaned_data.

• Form.has_error(field, code=None)

This method returns a boolean designating whether a field has an error with a specific error code. If code is None, it will return True if the field contains any errors at all.

To check for non-field errors use NON_FIELD_ERRORS as the field parameter.

• Form.non_field_errors()

This method returns the list of errors from Form.errors that aren’t associated with a particular field. This includes ValidationErrors that are raised in Form.clean() and errors added using Form.add_error(None, "...").

关于django中怎么利用 forms实现错误处理就分享到这里了，希望以上内容可以对大家有一定的帮助，可以学到更多知识。如果觉得文章不错，可以把它分享出去让更多的人看到。

创新互联www.cdcxhl.cn，专业提供香港、美国云服务器，动态BGP最优骨干路由自动选择，持续稳定高效的网络助力业务部署。公司持有工信部办法的idc、isp许可证， 机房独有T级流量清洗系统配攻击溯源，准确进行流量调度，确保服务器高可用性。佳节活动现已开启，新人活动云服务器买多久送多久。

新闻名称：django中怎么利用forms实现错误处理-创新互联
本文地址：http://sczitong.cn/article/ipgse.html