ArcObjects Library Reference (System)  

IExtension Interface

Provides access to members that define an extension.

Product Availability

Available with ArcGIS Engine, ArcGIS Desktop, and ArcGIS Server.


IExtension is implemented by developers of custom extensions. You do not normally use this interface from client code, other than to get the name of the extension.

Any extension that is registered with an application is automatically loaded and unloaded by the application; the end user does nothing to load or unload. For example, an extension that has been added to the ESRI Mx Extensions category will be started when ArcMap is started and will be shutdown when ArcMap is shutdown.

When To Use

Use the IExtension interface to query the properties of an extension or to create your own extension.

When you are creating a new extension, you need to implement the IExtension interface in your class code. This interface allows you to set the name of the extension and specify what action takes place when the extension is started or shutdown.


Read-only property Name The name of the extension.
Method Shutdown Shuts down the extension.
Method Startup Starts up the extension with the given initialization data.

CoClasses that implement IExtension

CoClasses and Classes Description
Adjustment (esriEditorExt) The Adjustment Tools Editor Extension.
AnimationExtension (esriAnimation) The Animation Extension Object.
AnnotationConstructionWindow (esriEditor) The Annotation Construction Window.
AnnotationEditExtension (esriEditor) An editor extension for creating and editing annotation features.
ArcPressExtension (esriOutputExtensions) Class that controls the ArcPress Extension.
ArcToolboxExtension (esriGeoprocessingUI)
AttributeWindow (esriEditor) Dialog for inspecting selected/editable features.
CadastralEditorExtension (esriCadastralUI) Cadastral Editor Extension Object.
CenterlinesSnap (esriArcScan) Snap agent that snaps to the centerlines of a raster.
ConflictsWindow (esriEditor) Window used to resolve versioning conflicts.
ConstructionMiniBar (esriEditor) An editor extension for creating and editing annotation features.
CornerSnap (esriArcScan) Snap agent that snaps to the corners of a raster.
DddEnvironment (esri3DAnalystUI) 3D Environment singleton object.
DddServerEnvironment (esriGeoDatabase) 3D Server Environment (license) singleton object.
DigitizerExtension (esriEditor) Extension for working with the digitizer.
DimensionEditExtension (esriEditor) An editor extension for creating and editing dimension features.
Editor (esriEditor) The Object Editor Extension.
EditorSnapping (esriEditorExt) Controls the editing specific snapping environment.
EndsSnap (esriArcScan) Snap agent that snaps to the ends of a raster.
EngineEditor (esriControls) A singleton object representing the Engine editing environment.
EngineNetworkAnalystEnvironment (esriControls) A singleton object representing Engine Network Analyst environment.
EngineSnappingWindow (esriControls)
FeatureSnap (esriEditor) Snap agent that snaps to a feature in a specified way.
FMEExtension (esriDataInteropUI) FMEExtension Class
FMEExtensionHelper (esriDataInterop) FMEExtensionHelper Class
GNetExtension (esriArcMapUI) GNet Extension.
GpsExtension (esriArcMapUI) The GPS extension object.
GPToolCommandManager (esriGeoprocessingUI) The Geoprocessoring tool command manager.
HatchExtension (esriLocationUI) A container for defining the route hatching extension and describing its current state.
IntersectionSnap (esriArcScan) Snap agent that snaps to the intersections of a raster.
LicensedDataExtension (esriDataSourcesFile) The Licensed Data Extension.
LocatorExtension (esriLocationUI) An extension for locators in ArcMap.
MAExtension (esriDefenseSolutions) Provides information about MAExtension.
MaplexExtension (esriMaplexUI) Represents the Maplex Extension.
MetadataExtension (esriCatalogUI) Provides access to metadata extension.
NADirectionsWindowManager (esriNetworkAnalystUI) Network Analyst Directions Window Manager Class.
NetworkAnalystExtension (esriNetworkAnalystUI) The extension for network analysis.
Publisher (esriPublisherUI) The Publisher Extension coclass.
RasterCleanup (esriArcScan) The Raster Cleanup Extension.
SAExtension (esriSpatialAnalystUI) Spatial Analyst Extension Object.
SchematicExtension (esriSchematicUI) Provides access to the schematic extension.
SelectionResolutionChip (esriEditor) An editor extension for resolving selection of multiple features.
SketchPropertiesWindow (esriEditor) Dialog for modifying sketch geometry.
Snapping (esriControls) Provides the snapping environment for tools to use.
SolidSnap (esriArcScan) Snap agent that snaps to the solids of a raster.
SpaceNavigatorExtension (esriGlobeCore) SpaceNavigatorExtension Class
TAExtension (esriTrackingAnalystUI) Defines the coclass for the TAExtension implementation.
TopologyExtension (esriEditorExt) Extension for working with topology.
TrackingEngineUtil (esriTrackingAnalyst) A general purpose Utility object for Tracking Analyst that provides a common way to access and determine the processing environment.
TraverseWindow (esriEditor) Dialog for creating traverses.
UtilityNetworkAnalysisExt (esriEditorExt) A container for defining the Utility Network Analysis extension and describing its current state.
Vectorization (esriArcScan) The Vectorization ArcMap Extension.


If you want your extension to be exposed in the Extensions dialog, you would also implement the IExtensionConfig interface. The class module for your extension would implement both IExtension and IExtensionConfig.

See Also

IApplication.FindExtensionByName Method | IApplication.FindExtensionByCLSID Method | IExtensionAccelerators Interface | IExtensionConfig Interface | IExtensionManager Interface

.NET Snippets

Get Extension | Get Editor from ArcMap | Display Extension State on Status Bar |

.NET Samples

Creating a zoom factor extension that works with a ToolbarControl (Code Files: SetZoomFactor ZoomIn ZoomOut) | Editing using a custom form (Code Files: EditorForm) | Implementing a schematic digitizing tool (Code Files: DigitTool DockableDigit) | Network Analyst Engine application (Code Files: frmMain) | Schematic diagram auto refresh (Code Files: Autorefresh) |

.NET Related Topics

3DAnalystUI | How to find an extension | How to migrate from COM components to add-ins | How to use extensions | How to work with the operation stack | LocationUI | MaplexUI | Working with the ArcGIS snapping environment |