Complete ComboBox Implementation with Full API Support

Description

This PR implements comprehensive ComboBox support for pyRevit extensions, exposing all properties and methods from the Autodesk.Revit.UI ComboBox API. The implementation enables full control over ComboBox creation, member management, and property configuration through bundle.yaml metadata.

The ComboBox implementation follows the same SmartButton pattern for deferred initialization, using the __selfinit__ function in script.py to allow scripts to access the fully constructed UI object and set up event handlers after the UI is created.

Combobox UI Element

Key Features

• Full Property Support: All ComboBox properties are now accessible (Name, ToolTip, Image, ItemText, Enabled, Visible, Current, LongDescription, ToolTipImage)
• Complete Method Implementation: All ComboBox methods are exposed (add_item, add_items, add_separator, get_items, etc.)
• Rich Member Metadata: ComboBox members support icons, tooltips, groups, extended tooltips, and tooltip images
• Event Handling: Support for CurrentChanged, DropDownOpened, and DropDownClosed events via __selfinit__ pattern (following SmartButton architecture)
• Proper Property Setting: Fixed member property assignment to work on ComboBoxMember objects (not ComboBoxMemberData)
• SmartButton Pattern: Uses deferred initialization via __selfinit__ function, consistent with SmartButton implementation

Technical Changes

1. components.py: Fixed member dictionary preservation - was converting rich metadata to simple tuples, losing icon/tooltip/group properties
2. ribbon.py: Added complete _PyRevitRibbonComboBox class with all API methods and properties
3. uimaker.py: Enhanced ComboBox creation to set all properties from metadata and properly configure members. Implements __selfinit__ pattern (SmartButton pattern) for deferred script initialization

Bug Fixes

• Fixed member icons/tooltips not appearing by preserving full member dictionaries
• Fixed property setting by using ComboBoxMember objects returned from AddItem()
• Added encoding declaration to fix non-ASCII character syntax error
• Fixed icon path resolution for member icons

Checklist

Before submitting your pull request, ensure the following requirements are met:

• Code follows the PEP 8 style guide.
• Code has been formatted with Black using the command:

  pipenv run black {source_file_or_directory}

• Changes are tested and verified to work as expected.

Related Issues

If applicable, link the issues resolved by this pull request:

• Related to ComboBox support feature request

Additional Notes

Files Modified

• pyrevitlib/pyrevit/extensions/components.py - Fixed member dictionary preservation
• pyrevitlib/pyrevit/coreutils/ribbon.py - Added complete ComboBox wrapper class
• pyrevitlib/pyrevit/loader/uimaker.py - Enhanced ComboBox creation and member configuration

Architecture Pattern

The ComboBox implementation follows the SmartButton pattern for deferred initialization:

1. UI is created and configured from bundle.yaml metadata
2. script.py is loaded as a module
3. If __selfinit__ function exists, it's called with (component, ui_item, uiapp) parameters
4. Script can access the fully constructed UI object to set up event handlers and perform custom initialization
5. If __selfinit__ returns False, the ComboBox is deactivated

This pattern allows scripts to:

• Access the ComboBox UI object after it's fully created
• Set up event handlers (CurrentChanged, DropDownOpened, DropDownClosed)
• Perform custom initialization logic
• Access all ComboBox properties and methods

Usage Example

ComboBoxes can now be created with full metadata support in bundle.yaml:

title: Panel Selector
tooltip: Switch between panels
tooltip_ext: Extended description
icon: icon.png
media_file: tooltip.png
members:
  - id: "settings"
    text: "Settings"
    icon: icon_settings.png
    tooltip: "Open Settings panel"
    tooltip_ext: "Configure settings"
    group: "Main Panels"
  - id: "views_sheets"
    text: "Views & Sheets"
    icon: icon_views.png
    tooltip: "Open Views & Sheets panel"
    group: "Main Panels"

And in script.py, use the __selfinit__ pattern to wire ComboBox items to commands:

def __selfinit__(component, ui_item, uiapp):
    """Deferred initializer - called after UI is created."""
    cmb = ui_item.get_rvtapi_object()
    
    # Define your command functions
    def show_settings():
        # Your logic here
        pass
    
    def show_views_sheets():
        # Your logic here
        pass
    
    # Map ComboBox member IDs to functions
    # The 'id' field from bundle.yaml members is used as the key
    FUNCTION_MAP = {
        "settings": show_settings,
        "views_sheets": show_views_sheets,
        # You can also map by display text as fallback
        "Settings": show_settings,
        "Views & Sheets": show_views_sheets,
    }
    
    def on_current_changed(sender, args):
        """Handle ComboBox selection change."""
        try:
            # Get the currently selected item
            current = sender.Current
            if not current:
                return
            
            # Access the member's ID and display text
            selected_id = current.Name      # The 'id' from bundle.yaml
            selected_text = current.ItemText  # The 'text' from bundle.yaml
            
            # Look up the function to call
            func = FUNCTION_MAP.get(selected_id) or FUNCTION_MAP.get(selected_text)
            
            if func:
                # Execute the command
                func()
            else:
                # Handle unknown selection
                logger.warning("No handler for: {} ({})".format(selected_text, selected_id))
        except Exception as e:
            logger.error("Error in ComboBox handler: {}".format(e))
    
    # Hook the event handler
    ui_item.add_current_changed_handler(on_current_changed)
    
    # Keep reference to prevent garbage collection
    ui_item._current_changed_handler = on_current_changed
    
    return True  # Return False to deactivate ComboBox

Key Points:

• The id field from bundle.yaml members becomes the Name property of the ComboBoxMember
• The text field becomes the ItemText property
• Use sender.Current.Name to get the member ID for routing to commands
• Use sender.Current.ItemText to get the display text
• Create a mapping dictionary (FUNCTION_MAP) to connect member IDs to your command functions
• The event handler receives the ComboBox sender and event args, allowing access to the selected member

API Methods Available

All ComboBox properties and methods from Autodesk.Revit.UI are now accessible:

• Properties: name, current, visible, enabled, get_title(), etc.
• Methods: set_icon(), set_tooltip(), add_item(), get_items(), etc.
• Events: CurrentChanged, DropDownOpened, DropDownClosed (via add_*_handler() methods)

Gotchas

• Thread Context: Do not use print() or equivalent logging inside the __selfinit__ initialization phase, as the thread context will break. Use logger from pyrevit.script instead:

  from pyrevit import script
  logger = script.get_logger()
  logger.warning("This works correctly")

• Member Icons: Using image (or icon) for ComboBox member items can yield strange UI behavior in Revit's ComboBox dropdown. The items may appear with extra padding/margin, pushing text to the right. This is a limitation of the Revit API's ComboBox rendering and is not controllable via the Ribbon API. Consider using icons sparingly or testing thoroughly if visual alignment is critical.

Testing

Tested with Spectrum extension ComboBox implementation. All member icons, tooltips, and properties are working correctly. Event handlers work as expected using the __selfinit__ pattern.

Reviewers

• @jmcouffin

FYI

• @WaynePatrickDalton

Thank you for contributing to pyRevit! 🎉