How do I customize a column based on its value? - django

Question

Using django-tables2 is very easy from your model to get a table. In my case I need one of my table columns to be formated based on its value.
In my current html table it would look like below:
{% if record.status|stringformat:"s" == "New" %}
<td class="bg-success></td>
If the value is New the cell background should be green.
From what I could find there are maybe 3 ways to do something like this:
Updated solutions:
1.Create a class and a css rule with the appropriate background color and add it to the column:
class MyTable(tables.Table):
status = tables.Column(attrs={"class": lambda record: record.status})
.New {
background-color: green
}
This way it works, although I think that record.status could work, without the lambda.
2.You can specify how to render a column:
class MyTable(tables.Table):
status = tables.Column()
def render_status(self, value):
if value.name == "New":
change class accordingly
The change class accordingly part eludes me.
Also you can create a custom column:
class StatusColumn(tables.Column):
def render(self, value):
if value == "New":
return format_html('<span class="text-success">{}</span>', value)
I made this work using a span tag to pass a bootstrap class to format the cell.
3.Use a TemplateColumn and pass html:
class MyTable(tables.Table):
status = tables.TemplateColumn("""
{% if record.status|stringformat:"s" == "New" %}
<td class="bg-success"></th>
{% else %}
<td class="bg-danger"></th>
{% endif %}
""")
This way a new column is created formated correctly.
I am still searching how to do this and I would appreciate any help.

Answer 1

Depending on what your exact needs are, there are different solutions.
1. Changing the appearance of the cell (<td></td>)
If you want to add attributes to the <td> tag, you must use something django-tables2 calls column attributes.
It supports fixed values, but also allows a callable to use some value of the record being rendered.
Say for instance, you have a record containing a field color and you want to use that color as the background color for the cell.
class Table(tables.Table):
person = tables.Column(attrs={
'td': {
'class': 'person-column',
'style': lambda record: 'background-color: {}'.format(record.color)
}
})
Or more specifically for your example:
class MyTable(tables.Table):
status = tables.Column(attrs={'td': {'class': lambda value: 'bg-success' if value == 'New' else 'bg-danger' }})
or without lambda:
def status_attr(record):
return 'bg-success' if value == 'New' else 'bg-danger'
class MyTable(tables.Table):
status = tables.Column(attrs={'td': {'class': status_attr}})
2. changing the contents of the cell
By contents I mean everything within the <td></td> tag. The API of django-tables2 allows for various ways to change the contents of a cell, which is called custom data in the documentation.
Your solutions 2 and 3 already show the ways to do that, however, you can not change the cell attributes in those ways. You might be able to achieve output looking like this <td><td class="bg-success">...</td></td>, which might look like what you want, but are not valid HTML.