如果存在用户创建的方法实例，则显示它们，否则显示字符串 Django

Question

code:

views.py:

@login_required(login_url='loginPage')
def boardPage(request):
    if Board.objects.filter(user=request.user).exists():
        boards = get_list_or_404(Board, user=request.user)
        context = {'boards': boards}
        return render(request, 'tasks/boards.html', context)
    else:
        context = {'boards': False}
        return render(request, 'tasks/boards.html', context)

boards.html:

{% extends 'tasks/main.html' %}
{% block content %}
    <center>board page<hr>
        <a href="{% url 'boardAdd' %}">add board</a> <br><br>
        your boards: <br> <br>
        {% if boards is false %}
            <p>you don't have any boards... Have you tried creating one? ;)</p>
        {% else %}
            {% for board in boards %}
                <a href="{% url 'insideBoard' board.id %}">{{board}}<br></a>
            {% endfor %}
        {% endif %}
        <br>
        <br>
        <hr>
        <a href="{% url 'logoutPage' %}">Logout</a>
    </center>
    {% if messages %}
        {% for message in messages %}
            <u><br>{% if message.tags %} {% endif %}>{{ message }}</u>
         {% endfor %}
    {% endif %}
{% endblock %}

models.py:

class Board(models.Model):
    title = models.CharField(max_length=50, null=True)
    user = models.ForeignKey(User, null=True, on_delete=models.CASCADE)

    def __str__(self):
        return self.title

class Task(models.Model):
    title = models.CharField(max_length=200, null=True)
    done = models.BooleanField(default=False, null=True)
    created_at = models.DateTimeField(auto_now_add=True, null=True)
    user = models.ForeignKey(User, null=True, on_delete=models.CASCADE)
    board = models.ForeignKey(Board, null=True, on_delete=models.CASCADE)
    due_to = models.DateField(null=True, validators=[dateValidation])

    def __str__(self):
        return self.title

every time user deletes all of his/her boards or new user visits that page (new users doesn't have any boards yet, they are able to create one there) I get "TypeError at / 'bool' object is not iterable" how do I need to change the code to see a string instead of instances of class on that page?

Answer 1

You don't need to add new variable, just check if array is empty. You are getting error as you are trying to iterate over Boolean in your template ( {'boards': False} )

@login_required(login_url='loginPage')
def boardPage(request):
        boards = Board.objects.filter(user=request.user)
        context = {'boards': boards}
        return render(request, 'tasks/boards.html', context)

---

{% extends 'tasks/main.html' %}
{% block content %}
    <center>board page<hr>
        <a href="{% url 'boardAdd' %}">add board</a> <br><br>
        your boards: <br> <br>
        {% if not boards %}
            <p>you don't have any boards... Have you tried creating one? ;)</p>
        {% else %}
            {% for board in boards %}
                <a href="{% url 'insideBoard' board.id %}">{{board}}<br></a>
            {% endfor %}
        {% endif %}
        <br>
        <br>
        <hr>
        <a href="{% url 'logoutPage' %}">Logout</a>
    </center>
    {% if messages %}
        {% for message in messages %}
            <u><br>{% if message.tags %} {% endif %}>{{ message }}</u>
         {% endfor %}
    {% endif %}
{% endblock %}