默认情况下，如何设置Django ModelForm菜单项？ [英] How do I make a Django ModelForm menu item selected by default?

问题描述

我正在处理一个Django应用程序。我的一个模型用户包含一个性别字段，定义如下：

  GENDER_CHOICES =（
（'M'，'男'），
（'F'，'女'），
）
 gender = models.CharField（max_length = 1，choices = GENDER_CHOICES，null =我正在使用一个ModelForm来生成一个新用户HTML表单。我的Google-fu似乎失败了我 - 如何使这个HTML表单默认在下拉框中选择男项？ （即这样 selected =selected）
解决方案
如果您需要选择默认值的空白表单，请使用您的字段的名称作为密钥，将初始字典传递给模型表单的构造函数：
  form = MyModelForm（initial = {'gender'：'M'}）
  
 -OR  -  
 
 
 
您可以使用Forms API的声明性来覆盖ModelForm的某些属性。但是，对于这种用例来说，这可能有点麻烦，我只提到你可以做到这一点。您可能会在将来找到其他用途。
  class MyModelForm（forms.ModelForm）：
 gender = forms .ChoiceField（choices = ...，initial ='M'，...）
 class Meta：
 model = MyModel 
  
 -OR  -  
 
 
 
如果你想要一个绑定到模型的特定实例的ModelForm，你可以传递您的模型的实例，导致Django从该模型中拉取所选值。 
  form = MyModelForm（instance = someinst）
  
 
I am working on a Django app. One of my models, "User", includes a "gender" field, as defined below:
GENDER_CHOICES = (
        ('M', 'Male'),
        ('F', 'Female'),
    )
gender = models.CharField(max_length=1, choices=GENDER_CHOICES, null=True)
I am using a ModelForm to generate a "new user" HTML form. My Google-fu seems to be failing me -- how can I make this HTML form have the "Male" item selected by default in the drop-down box? (i.e. so selected="selected" for this item.)
解决方案
If you need a blank form with a default value selected, then pass an 'initial' dictionary to the constructor of your model form using the name of your field as the key:
form = MyModelForm (initial={'gender':'M'})
-OR-

You can override certain attributes of a ModelForm using the declarative nature of the Forms API.  However, this is probably a little cumbersome for this use case and I mention it only to show you that you can do it.   You may find other uses for this in the future.
class MyModelForm (forms.ModelForm):
    gender = forms.ChoiceField (choices=..., initial='M', ...)
    class Meta:
        model=MyModel
-OR-

If you want a ModelForm that is bound to a particular instance of your model, you can pass an 'instance' of your model which causes Django to pull the selected value from that model.  
form = MyModelForm (instance=someinst)


                        
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