如何使用Django FileField在模板中显示当前文件 [英] How to show current file in templates with Django FileFields

问题描述

我有点卡住了，我一直在使用Django一段时间，但我似乎无法找到这个东西了。这很奇怪，因为它应该是一个简单的事情。

我一直在搜索，似乎无法找到解决方案，这可能是因为它是一个简单的事情。

问题是，我有一个ModelForm，它有一个FileField，当我用这个模型的一个实例渲染这个表单，并且这个对象包含一个上传的文件，我想显示当前的文件，（像管理员那样），但我似乎无法做到这一点。

这些技术都无法工作：

  {{form.as_p}} 
 {{field.label_tag}} 
  

我一直在管理员模板中搜索，但似乎无法找到魔术。表单正确呈现对象的所有其他数据

问题2是因为上传的文件在用对象的实例呈现更改表单时没有显示，那么当我尝试保存时，表单无法验证，因为它对之前上传的文件一无所知。

那么如何处理Django中变化形式的文件字段，如何显示当前上传的文件，以及如何验证表单。 解决方案

这个解决方案是一个在contrib / admin / widgets.py中的自定义小部件，也就是这个：

  class AdminFileWidget（forms.FileInput） ：

一个FileField Widget，如果有的话显示它的当前值

 def __init __（self，attrs = {}）：
超级（AdminFileWidget，self）.__ init __（attrs）
 $ b $ def命令（self，name，value，attrs = None）：
 output = [] 
 if hasattr（value，url）：
 output.append（'％s< a target =_ blankhref =％s>％s< / a> < br />％s'％\ 
（_（'Currently：'），value.url，value，_（'Change：'）））
 output.append（super AdminFileWidget，self）.render（name，value，attrs））
 return mark_safe（u''。join（output））
  

您可以使用这个（或改编版本）使用

据我所知，你的第二个选项是默认字段类型或小部件 =nofollow noreferrer>小部件meta选项。问题不应该在那里，即使没有一个更好的小部件，让它知道它是否仍然使用自定义小部件后仍然存在。

I am kinda stuck, I've been using Django for a while now, but I cant actually seem to find this thing out. And thats weird because it should be a simple thing.

I've been googling around and can't seem to find a solution, it maybe because it is a simple thing.

The problem is, I have a ModelForm, and it has a FileField, when I render this form with an instance of the model, and the object contains an uploaded file, I would like to show the current file, (like the admin does), but I cant seem to do that.

Neither of these techniques work:

{{ form.as_p }}
{{ field.label_tag }}

I've been searching around in the admins templates, but can't seem to find the magic. The form renders all the other data of the object correctly

Problem number 2 is that since the uploaded file doesn't show when rendering a change form with a instance of an object, the forms fail to validate when i try to save since it knows nothing about the file that was previously uploaded.

So how do you handle filefields in a change form in Django, how to show the current uploaded file, and how to validate the form.

解决方案

You didn't look around well enough, the solution is a custom widget in contrib/admin/widgets.py, namely this one:

class AdminFileWidget(forms.FileInput):
    """
    A FileField Widget that shows its current value if it has one.
    """
    def __init__(self, attrs={}):
        super(AdminFileWidget, self).__init__(attrs)

    def render(self, name, value, attrs=None):
        output = []
        if value and hasattr(value, "url"):
            output.append('%s <a target="_blank" href="%s">%s</a> <br />%s ' % \
                (_('Currently:'), value.url, value, _('Change:')))
        output.append(super(AdminFileWidget, self).render(name, value, attrs))
        return mark_safe(u''.join(output))

You can use this (or an adapted version) using the widgets meta option of ModelForms.

As far as I know your second problem shouldn't be there at all, even without a nicer widget, let it know if it still persists after using a custom widget.

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