我是 Django 新手。我试图建立一个基本的牙医网站，可供患者用于预约，作为一个实践项目。
我面临的问题是我无法动态显示可用时段，以防止重复预订。时间段字段显示为空白。
我尝试在 Django 表单本身的构造函数中构建逻辑，以便当用户选择日期时仅显示可用的时间段。
Django 形式是：
`from django import forms
from django.forms.widgets import DateInput
from .models import Appointment
class DatePickerInput(DateInput):
def __init__(self, *args, **kwargs):
attrs = kwargs.get('attrs', {})
attrs.update({'data-provide': 'datepicker','data-date-start-date': '0d'})
kwargs['attrs'] = attrs
super().__init__(*args, **kwargs)
class AppointmentForm(forms.Form):
first_name = forms.CharField(max_length=100, widget=forms.TextInput(attrs={'class': 'form-control ', 'placeholder': 'First Name'}))
last_name = forms.CharField(max_length=100, widget=forms.TextInput(attrs={'class': 'form-control ', 'placeholder': 'Last Name'}))
age = forms.IntegerField(widget=forms.NumberInput(attrs={'class': 'form-control ', 'placeholder': 'Age'}))
date = forms.DateField(
widget=DatePickerInput(
attrs={'class': 'form-control datepicker px-2', 'placeholder': 'Date of visit'}
)
)
time_slot = forms.ChoiceField(choices=[('', 'Select Time Slot')] + [(option, option) for option in [
'09:00 AM', '10:00 AM', '11:00 AM', '12:00 PM', '02:00 PM', '03:00 PM', '04:00 PM', '05:00 PM', '06:00 PM', '07:00 PM',
]], widget=forms.Select(attrs={'class': 'form-control'}))
contact_number = forms.CharField(max_length=15, widget=forms.TextInput(attrs={'class': 'form-control ', 'placeholder': 'Contact Number'}))
email = forms.EmailField(required=False, widget=forms.EmailInput(attrs={'class': 'form-control ', 'placeholder': 'Email'}))
treatment_needed = forms.ChoiceField(choices=[('', 'Select Treatment')] + [(option, option) for option in [
'Apicectomy', 'Bone grafting', 'Ceramic venner/laminates', 'Cast partial denture', 'Consultation',
'Dental filling', 'Dental implants', 'Dental implants crown', 'Direct sinus lift surgery', 'E-max crown',
'Gum depigmentation', 'Gum recontouring/gum esthetic surgery', 'IOPA X-Ray', 'Inlay/onlay composite',
'Inlay/onlay metallic', 'Indirect sinus lift surgery', 'Metal Ceramic Crown', 'Metal Crown', 'Operculectomy',
'Orthodontic ceramic braces', 'Orthodontic metallic braces', 'Orthodontic self-ligating ceramic braces',
'Orthodontic treatment (aligners)', 'Orthodontic treatment (self-ligating metallic braces)',
'Pediatric Root canal Treatment with metal cap', 'Pediatric Root canal Treatment with zirconia cap',
'Pediatric dental filling', 'Pediatric extraction', 'Pediatric fluoride application (each arch)',
'Pediatric scaling & polishing', 'Pediatric space maintainer', 'Periodontal flap surgery',
'Pit & fissure sealant', 'Post & Core', 'Post Root canal treatment Filling (Composite)',
'Premium dental implant', 'Removable acrylic partial denture', 'RE-Root canal treatment', 'Root canal Treatment',
'Scaling & polishing', 'Simple extraction/tooth removal', 'Smile designing', 'Specialized complete denture',
'Std.complete denture', 'Surgical extraction/wisdom tooth removal', 'Teeth Whitening',
]], widget=forms.Select(attrs={'class': 'form-control '}), required=False)
notes = forms.CharField(required=False, widget=forms.Textarea(attrs={'class': 'form-control ', 'rows': 5, 'placeholder': 'Write your notes or questions here...'}))
def __init__(self, *args, **kwargs):
super().__init__(*args, **kwargs)
selected_date = self.data.get('date')
if selected_date:
booked_appointments = Appointment.objects.filter(date=selected_date).values_list('time_slot', flat=True)
all_time_slots = [
'09:00 AM', '10:00 AM', '11:00 AM', '12:00 PM', '02:00 PM',
'03:00 PM', '04:00 PM', '05:00 PM', '06:00 PM', '07:00 PM',
]
available_time_slots = [slot for slot in all_time_slots if slot not in booked_appointments]
self.fields['time_slot'].choices = [('', 'Select Time Slot')] + [(slot, slot) for slot in available_time_slots]
`
模型类是：
`
from django.db import models
class Appointment(models.Model):
first_name = models.CharField(max_length=100)
last_name = models.CharField(max_length=100)
age = models.IntegerField()
date = models.DateField()
time_slot = models.CharField(max_length=20)
contact_number = models.CharField(max_length=10)
email = models.EmailField()
treatment_needed = models.CharField(max_length=100)
notes = models.TextField()
is_available = models.BooleanField(default=True)`
预约表格的 HTML 模板是：
<form method="post" action="{% url 'home' %}" class="p-5 bg-white">
{% csrf_token %}
<div class="row form-group">
<div class="col-md-6 mb-3 mb-md-0">
<label class="font-weight-bold" for="{{ appointment_form.first_name.id_for_label }}">First Name*</label>
{{ appointment_form.first_name }}
</div>
<div class="col-md-6">
<label class="font-weight-bold" for="{{ appointment_form.last_name.id_for_label }}">Last Name*</label>
{{ appointment_form.last_name }}
</div>
</div>
<div class="row form-group">
<div class="col-md-6 mb-3 mb-md-0">
<label class="font-weight-bold" for="{{ appointment_form.age.id_for_label }}">Age*</label>
{{ appointment_form.age }}
</div>
<div class="col-md-6">
<label class="font-weight-bold" for="{{ appointment_form.contact_number.id_for_label }}">Contact Number*</label>
{{ appointment_form.contact_number }}
</div>
</div>
<div class="row form-group">
<div class="col-md-6 mb-3 mb-md-0">
<label class="font-weight-bold" for="{{ appointment_form.date.id_for_label }}">Date*</label>
{{ appointment_form.date }}
</div>
<div class="col-md-6 mb-3 mb-md-0">
<label class="font-weight-bold">Time Slot*</label>
{{ appointment_form.time_slot }}
<!-- Error message div for Time Slot -->
<div id="time_slot_error" class="text-danger">
{% if error_message %}
{{ error_message }}
{% endif %}
</div>
</div>
</div>
<div class="row form-group">
<div class="col-md-12">
<label class="font-weight-bold" for="{{ appointment_form.email.id_for_label }}">Email</label>
{{ appointment_form.email }}
</div>
</div>
<div class="row form-group">
<div class="col-md-12">
<label class="font-weight-bold" for="{{ appointment_form.treatment_needed.name }}">Treatment Needed</label>
{{ appointment_form.treatment_needed }}
</div>
</div>
<div class="row form-group">
<div class="col-md-12">
<label class="font-weight-bold" for="{{ appointment_form.notes.id_for_label }}">Notes</label>
{{ appointment_form.notes }}
</div>
</div>
<div class="row form-group">
<div class="col-md-12">
<input type="submit" value="Send" class="btn btn-primary">
</div>
</div>
</form>
如果您使用
postgresDateTimeRangeField