Providing input values from a (sub-) category
Using input type "tree"
(see official documentation: mediawiki.org/wiki/Extension:Page_Forms/Input_types#tree )
{{{field|doctype|input type=tree|top category=Document type|depth=1|hideroot|list}}}
Form display:
Example output of template parameter: doctype=Process
Using DPL query (dropdown)
(Solution found at: https://www.mediawiki.org/wiki/Extension_talk:DynamicPageList3#Return_page_titles_as_plain_text?
{{{field
| doctype
| input type=dropdown
| values = {{#dpl: namespace = Category
| category = Document type
| mode = inline
| format = ,¶%TITLE%,,
| inlinetext = ,
}}
}}}
Form field:
Example template output:
doctype=Process
Using an SMW concept
Create the page Concept:Doctype with the following content:
{{#concept:
[[Subcategory of::Documenttype]][[Modification date::+]]
|List of sub categories of the category Documenttype
}}
Use this concept as the source for the values of your field:
{{{field|doctype|input type=dropdown|values from concept=doctype|mapping template=catConcept}}}
The above example uses the mapping template Template:catConcept to avoid showing the namespace prefix "Category:" in the dropdown. Create the template with the following content:
{{PAGENAME:{{{1|}}}
Although the category prefix is then not shown in the dropdown, the value the form passes to its associated template parameter still includes the namespace prefix.
Example template output:
doctype=Category:Process