Namespaces
- Autodesk.Revit.ApplicationServices
- Autodesk.Revit.Attributes
- Autodesk.Revit.Creation
- Autodesk.Revit.DB
- Autodesk.Revit.DB.Analysis
- Autodesk.Revit.DB.Architecture
- Autodesk.Revit.DB.DirectContext3D
- Autodesk.Revit.DB.Electrical
- Autodesk.Revit.DB.Events
- Autodesk.Revit.DB.ExtensibleStorage
- Autodesk.Revit.DB.ExternalService
- Autodesk.Revit.DB.Fabrication
- Autodesk.Revit.DB.IFC
- Autodesk.Revit.DB.Infrastructure
- Autodesk.Revit.DB.Lighting
- Autodesk.Revit.DB.Macros
- Autodesk.Revit.DB.Mechanical
- Autodesk.Revit.DB.Plumbing
- Autodesk.Revit.DB.PointClouds
- Autodesk.Revit.DB.Steel
- Autodesk.Revit.DB.Structure
- Autodesk.Revit.DB.Structure.StructuralSections
- Autodesk.Revit.DB.Visual
- Autodesk.Revit.Exceptions
- Autodesk.Revit.UI
  - AddInCommandBinding Class
  - ButtonData Class
  - ColorSelectionDialog Class
  - ComboBox Class
    - ComboBox Properties
    - ComboBox Methods
    - ComboBox Events
      - CurrentChanged Event
      - DropDownClosed Event
      - DropDownOpened Event
  - ComboBoxData Class
  - ComboBoxMember Class
  - ComboBoxMemberData Class
  - CommandMenuItem Class
  - ContextMenu Class
  - ContextualHelp Class
  - ContextualHelpType Enumeration
  - DockablePane Class
  - DockablePaneId Class
  - DockablePaneProviderData Class
  - DockablePanes Class
  - DockablePanes.BuiltInDockablePanes Class
  - DockablePaneState Class
  - DockPosition Enumeration
  - DoubleClickAction Enumeration
  - DoubleClickOptions Class
  - DoubleClickTarget Enumeration
  - EditorInteraction Class
  - EditorInteractionType Enumeration
  - ExternalApplicationArray Class
  - ExternalApplicationArrayIterator Class
  - ExternalCommandData Class
  - ExternalCommandsData Class
  - ExternalEvent Class
  - ExternalEventRequest Enumeration
  - FaceBasedPlacementType Enumeration
  - FamilyInstancePlacingArgs Class
  - FileDialog Class
  - FileOpenDialog Class
  - FileSaveDialog Class
  - FilterDialog Class
  - IContextMenuCreator Interface
  - IControllableDropHandler Interface
  - IDockablePaneProvider Interface
  - IDropHandler Interface
  - IExternalApplication Interface
  - IExternalCommand Interface
  - IExternalCommandAvailability Interface
  - IExternalEventHandler Interface
  - IExternalResourceUIServer Interface
  - IFCExternalServiceUIData Class
  - IFrameworkElementCreator Interface
  - IIFCEntityTreeUIServer Interface
  - IRevisionsOnSheetUIServer Interface
  - ItemData Class
  - ITemporaryGraphicsHandler Interface
  - ItemSelectionDialogResult Enumeration
  - MenuItem Class
  - PostableCommand Enumeration
  - PreviewControl Class
  - ProjectBrowserOptions Class
  - PromptForFamilyInstancePlacementOptions Class
  - PulldownButton Class
  - PulldownButtonData Class
  - PushButton Class
  - PushButtonData Class
  - RadioButtonGroup Class
  - RadioButtonGroupData Class
  - Result Enumeration
  - RevisionsOnSheetUIServiceData Class
  - RevitCommandId Class
  - RevitLinkUIUtils Class
  - RibbonButton Class
  - RibbonButtonOptions Class
  - RibbonItem Class
  - RibbonItemData Class
  - RibbonItemType Enumeration
  - RibbonPanel Class
  - ScrollbarVisibility Enumeration
  - SelectionUIOptions Class
  - SeparatorItem Class
  - SketchGalleryOptions Enumeration
  - SplitButton Class
  - SplitButtonData Class
  - SubMenuItem Class
  - Tab Enumeration
  - TabbedDialogAction Delegate
  - TabbedDialogExtension Class
  - TableViewUIUtils Class
  - TaskDialog Class
  - TaskDialogCommandLinkId Enumeration
  - TaskDialogCommonButtons Enumeration
  - TaskDialogIcon Enumeration
  - TaskDialogResult Enumeration
  - TemporaryGraphicsCommandData Class
  - TextBox Class
  - TextBoxData Class
  - TextEditorOptions Class
  - ThemeType Enumeration
  - ThinLinesOptions Class
  - ToggleButton Class
  - ToggleButtonData Class
  - UIApplication Class
  - UIControlledApplication Class
  - UIDocument Class
  - UIFabricationUtils Class
  - UISaveAsOptions Class
  - UITheme Enumeration
  - UIThemeManager Class
  - UIView Class
- Autodesk.Revit.UI.Events
- Autodesk.Revit.UI.Macros
- Autodesk.Revit.UI.Mechanical
- Autodesk.Revit.UI.Plumbing
- Autodesk.Revit.UI.Selection
WhatsNew
Revit .NET 8 Upgrade Tips

ComboBox.DropDownOpened Event

Revit 2026 API

ComboBoxDropDownOpened Event

Subscribe to this event to be notified when the drop-down of the ComboBox is opened.

Namespace: Autodesk.Revit.UI
Assembly: RevitAPIUI (in RevitAPIUI.dll) Version: 26.0.4.0 (26.0.4.0)

Syntax

public event EventHandler<ComboBoxDropDownOpenedEventArgs> DropDownOpened

Public Event DropDownOpened As EventHandler(Of ComboBoxDropDownOpenedEventArgs)

public:
 event EventHandler<ComboBoxDropDownOpenedEventArgs^>^ DropDownOpened {
	void add (EventHandler<ComboBoxDropDownOpenedEventArgs^>^ value);
	void remove (EventHandler<ComboBoxDropDownOpenedEventArgs^>^ value);
}

member DropDownOpened : IEvent<EventHandler<ComboBoxDropDownOpenedEventArgs>,
    ComboBoxDropDownOpenedEventArgs>

Value

EventHandlerComboBoxDropDownOpenedEventArgs

Reference

ComboBox Class

Autodesk.Revit.UI Namespace

Send comments on this topic to Autodesk

E:Autodesk.Revit.UI.ComboBox.DropDownOpened