I have a Snippet model(SampleSnippet) with fields field_a, field_b, and field_c. And I am using it in a StructBlock like:
class SampleBlock(blocks.StructBlock):
service_snippet = SnippetChooserBlock(SampleSnippet)
...
Now I want to show some of the SampleSnippet fields(field_a and field_b) in SampleBlock after saving the SampleBlock for the first time(after saving the snippet) on the wagtail admin site. How can I achieve this? I looked around a lot but couldn't find a similar issue.
If it were a model/snippet, I could have used property with ReadOnlyPanel but in the case of a StructBlock, I am stuck and not getting any ideas. If anybody knows any way to achieve this, please help me out. Thanks in advance.
This is going to be quite difficult, since in current Wagtail versions (>=2.13) the StreamField editing UI is populated client-side in Javascript - as such, there are some extra steps to make the necessary data available to the client-side code, and the standard Django form / template mechanisms won't be available.
A simple workaround, if the fields aren't too long, would be to define the snippet's __str__ method to include the desired data - this will then display any time the snippet is shown in the admin.
For a full solution, I'd suggest this approach:
Set up a custom form_template for your StructBlock as detailed in Custom editing interfaces for StructBlock, with placeholder <div> elements to contain your additional data.
Override the StructBlock's get_form_state so that the returned dict (which will be used to populate the form template on the client side) includes your additional fields - something like:
def get_form_state(self, value):
data = super().get_form_state(value)
data['field_a'] = value['service_snippet'].field_a
data['field_b'] = value['service_snippet'].field_b
return data
Set up a custom JS adapter following the steps in Additional JavaScript on StructBlock forms. In the final render method, the data you returned from get_form_state will be available as initialState, and you can use this to populate the placeholder <div>s in the template.