The new SimpleForms extension is still under development, but is now functional. Here's an example which shows how to make a simple form for listing the articles in a category. The source is shown first, followed by the resulting form.
{{#form:
{{#input: type = select
| name = cat
| value = {{#request:cat}}
| *Select category {{#dpl: namespace = Category | mode = userformat | listseparators = ,\n*%TITLE%,, }}
}}
{{#input: type = submit | value = List members}}
}}
{{#if:
{{#request:cat}} | {{#dpl:category = {{#request:cat}} }}
}}
{{#form:
{{#input: type = select
name = cat
value = {{#request:cat}}
*Select category
3thirds
3thirds/Date
3thirds/Rooms
ACTIONSCRIPT
ADEFT.COM
ADEFT.COM/Testimonials
ASM
Accounts
ActionScript
Administrator
Aggregation
Alte Dokumente
Amber
Arhaus
Articles containing maths
Articles containing stuff
Articles containing trees
Articles containing warnings
Articles in need of clean up
Articles marked for deletion
Articles requiring expansion
Articles that need better colours
Articles that need links added
Articles that need updating
Articles with broken images
Audio
BASH
BIOS
Back burner
Backup
Bertrand Russell's The Problems of Philosophy
Best practice
BioC
Birds
Blog
Booklet
Books
Borromean rings
Brochures
Broken Examples
Bugs
Build system
BusinessPlan
Business Plan Objects
Business Plans
Business plans
C
CPP
CSS
Changes
Chef
Classes
Co-creators
Co-op
Code in the OD SVN repository
Code that uses voodoo
Collaborative work
Colours
Compilers
Completed Milestones
Completed projects
Computer user procedures
Config
Contact List
Contact Lists
Contact manager
Contacts
Cycles
DEUTSCH
DNA
Date
Debian
Debian packages
Demo
Descriptions
Design
Dev
Dev procedures
Development
Devonport
Diagrams
Director
Discussion requests
Distributed computing
Distributed processing
Documentaries
Documents
Domain names
Done
E-book
ENGLISH
ERP
Education
Education and Media
Emma
Emoticons
Erich
Examples
Examples/ACTIONSCRIPT
Examples/PHP
Examples/Semantic MediaWiki
Examples/Workflow
Examples/Workflow/Components
Extension summaries
Extensions
Extensions created with Template:Extension
Extensions created with Template:SpecialPage
Extensions in progress
Extensions in the MediaWiki SVN repository
Featured articles
Featured categories
Featured projects
Firebreather
Fliss
Flower
Flower/Contacts
Formatting templates
Friday meetings
GeSHi
German Lessons
Gliffy
Glossary
Glossary/Legal
Glue
Gock
Goldfinger/Thesis
Goldfinger/Thesis/Rcode
Goldfinger/Thesis/Tools
Graphs
Group:3thirds
Group:adeft
Group:streamline
Group processes
Groups
HTML4STRICT
Hardware
Help
Hosting
Human Resources
IR
IT Support
I am that
Icons
Images
Incomplete procedures
Installation
Interface
Inventory
JAVA
JAVASCRIPT
Jack
JavaScript
Jobs for money
Kat
Katikati Home Education
Kernel
Kiss
Languages
Legacy
Legacy Extensions
Legacy Projects
Limma
Links
Linux
Livelets
Living Together
LocalSettings
Mac
Mail
Mailouts
Manasi
Manifesto
MediaWiki
MediaWiki/GeSHi
MediaWikiLite
MediaWiki projects
MediaWiki workshop
Media Center
Meetings
Meridian
Meridian/Resources
Methodology
Microarray
Milan
Milan/Admin
Milan/BrokenListCat
Milan/Contact Groups
Milan/Contacts Biz
Milan/Contacts Sudesel
Milan/Contacts YPT
Milan/Current
Milan/Goals
Milan/Old School Contacts
Milan/Organisation
Milan/Resource
Milan/Role
Milan/Roles
Milan/WS
Milan Admin
Milestones
Mint Media
Nad
Nad/Todo
Networking
News
Newstuff
Nodal Applications
Nodal Concepts
Nodal Organisations
Node
Nodes
NomadIT
NomadIT/Clients
NomadIT/Suppliers
Notes
Nutrigenomics
Nutrigenomics/R
OD2
Obsolete Documents
Obsolete nodes
Old Projects
Old documents
OpenGL
Organic Design
Organic Design Services
Organisation
Organisational Templates
Organisational templates
Organisations
PERL
PERL/Tam
PFS Wiki Proposal
PHP
PYTHON
Peer
Peerd
Peerd/files/ActionScript
Peerd/files/C
Peerd/files/C/unused
Peerd/files/PERL
Peerix
Peers
Peers/Bender
Peers/Gir
People
People pictures
Perl
Perl/Tam
Perl packages
Phalseid/Date
Phalseid/Friend
Phalseid/Goals
Phalseid/Todo
Philosophy
Places
Platform
Portals
Prana/Forms
Prana/Marketing
Prana Group Members
Preferred Vendors
Private
Procedure
Procedures
Processes
Products
Project/Sanctuary
Project Developers
Project Friends
Project Management
Project Managment
Project booklet
Projects
Queries
Quotes
R
Real mode assembler
Records
Required semantic forms
Resources
Rob
Robots
Roles
SCHEME
SDL
SSL
SVG
SWF 3D space
SWF projects
Sandbox
Screenshots
Security Properties
Selenium
Selenium test suites
Selenium tests
Self-improvement
Seminars
Service Call
Services
Sh scripts that use braces syntax
Sh scripts that use bracket syntax
Skins
Smartcarpetcare.com
Snipits
Software
Special-Page Transforms
Storage
Streamline
Streamline/Todo
Structured Or Unstructured
Stubs
Subversion
Summaries
Surprise
Survey
Sven
Sven/Contacts
Sven/DSRNA feeding
Sven/Rosaceae
Symbols
Sysop procedures
TBD
TEX
TEXT
Teacher
Technology
Template Articles
Test
Todo
Training
Transforms
Tree view
Tree view images
Tribe/Meeting Minutes
USB turntable
Unity
User categories
Vision
Vtiger
WIP
Waiheke
Waiheke platform/Contacts
Web2.0
Webpages
Wharfit
Whitepaper
Wiki Templates
Wiki organisation
Wiki templates
Wiki user procedures
Wikia
Wikis
Wiklets
Work In Progress
Workflow categories
Workshops
XML
XSLT
XmlWiki
XmlWiki Components
XmlWiki Events
XmlWiki Properties
Yi
Zenovia
}}
{{#input: type = submit | value = List members}}
}}
Extension:DynamicPageList (DPL), version 1.8.9 : ERROR: No selection criteria found! You must use at least one of the following parameters: category, namespace, titlematch, linksto, uses, createdby, modifiedby, lastmodifiedby or their 'not' variants
