Django分页功能中用户自定义每页显示条数失效问题求助

Hey there! Let's fix that custom per-page count issue you're having. The problem boils down to a few small gaps in how your form submits data and how your pagination links preserve the selected per-page value. Here's how to get it working:

1. Fix the per_page handling in views.py #

Right now, you're grabbing per_page as an unvalidated string and falling back to 1 (which is probably not your intended default). Let's clean up the logic to handle validation, type conversion, and sensible defaults:

def finished_ads_view(request):
    queryset = Campaign.objects.filter(completion_percent=100)
    
    # Handle per_page with validation and reasonable default
    try:
        per_page = int(request.GET.get('dropdown', 10))  # Default to 10 if no input
        # Restrict to allowed values to prevent weird user inputs via URL
        if per_page not in [1, 2, 15, 20, 25]:
            per_page = 10
    except ValueError:
        # Catch non-integer values and use default
        per_page = 10

    page = request.GET.get('page', 1)
    paginator = Paginator(queryset, per_page)
    
    try:
        posts = paginator.page(page)
    except PageNotAnInteger:
        posts = paginator.page(1)
    except EmptyPage:
        posts = paginator.page(paginator.num_pages)
    
    context = {
        'posts': posts,
        'current_per_page': per_page,  # Pass current value to template for dropdown state
    }
    return render(request, 'finished_campaigns.html', context)

Key changes here:

• Use request.GET.get() instead of direct indexing to avoid KeyError when the parameter is missing
• Convert the value to an integer (since Paginator expects a numeric value)
• Add a check to ensure the value is one of your allowed options
• Pass current_per_page to the template so we can keep the dropdown synced with the user's selection

2. Fix the template form and pagination links #

Your form wasn't properly configured to submit via GET (matching how your view reads parameters), and pagination links didn't carry over the selected per-page value—so switching pages reset to the default. Here's the updated template code:

<!-- Wrap dropdown/submit in a GET form to pass parameters correctly -->
<form method="get" class="mb-3">
  <select name="dropdown" class="form-select d-inline-block w-auto">
    {% for option in [1,2,15,20,25] %}
    <option value="{{ option }}" {% if current_per_page == option %}selected{% endif %}>
      {{ option }}
    </option>
    {% endfor %}
  </select>
  <input type="submit" value="Update Page Size" class="btn btn-primary ms-2"/>
</form>

<nav aria-label="Page navigation">
  <ul class="pagination justify-content-center">
    {% if posts.has_previous %}
    <li class="page-item">
      <a class="page-link" href="?page=1&dropdown={{ current_per_page }}" aria-label="Previous">
        <span aria-hidden="true">&laquo;</span>
        <span class="sr-only">begin</span>
      </a>
    </li>
    {% endif %}
    {% for n in posts.paginator.page_range %}
    {% if posts.number == n %}
    <li class="page-item active">
      <span class="page-link">{{ n }}<span class="sr-only">(current)</span></span>
    </li>
    {% elif n > posts.number|add:'-3' and n < posts.number|add:'3' %}
    <li class="page-item">
      <a class="page-link" href="?page={{ n }}&dropdown={{ current_per_page }}">{{ n }}</a>
    </li>
    {% endif %}
    {% endfor %}
    {% if posts.has_next %}
    <li class="page-item">
      <a class="page-link" href="?page={{ posts.paginator.num_pages }}&dropdown={{ current_per_page }}" aria-label="Next">
        <span aria-hidden="true">&raquo;</span>
        <span class="sr-only">end</span>
      </a>
    </li>
    {% endif %}
  </ul>
</nav>

Key template fixes:

• Added a <form> tag with method="get" to ensure the dropdown value is submitted correctly
• Updated the dropdown to loop through allowed options and mark the current selection as selected
• Added &dropdown={{ current_per_page }} to all pagination links, so the selected page size persists when navigating between pages

Why this works: #

• The view now properly validates and converts the per-page value, with a sensible default
• The form submits the user's choice via GET, which matches how your view retrieves parameters
• All pagination links carry over the selected page size, so users don't lose their preference when switching pages

内容的提问来源于stack exchange，提问作者low_ratio