Event Types

About 4 min

Event Types

WebCAD provides a rich event system for listening to and responding to many kinds of operations.

Online Examples

Example	Description	Link
Entity Added Event	Listen to `EntityAdded`	Online Demo{target="_blank"}
Entity Modified Event	Listen to `EntityModified`	Online Demo{target="_blank"}
Selection Changed Event	Listen to `SelectionChanged`	Online Demo{target="_blank"}
Command Events	`CommandStarted` and `CommandEnded`	Online Demo{target="_blank"}
Document Events	`DocumentOpened` and `DocumentSaved`	Online Demo{target="_blank"}
Polyline Points & Event Timing	EntityAdded/EntityModified/CommandEnded differences during PLINE drawing	Online Demo{target="_blank"}

`CadEvents` Enum

enum CadEvents {
  // ===== Document Events =====
  DocumentCreating = 'DocumentCreating',    // Before create, cancelable
  DocumentCreated = 'DocumentCreated',      // After create
  DocumentOpening = 'DocumentOpening',      // Before open, cancelable
  DocumentOpened = 'DocumentOpened',        // After open
  DocumentClosing = 'DocumentClosing',      // Before close, cancelable
  DocumentClosed = 'DocumentClosed',        // After close
  DocumentSaving = 'DocumentSaving',        // Before save, cancelable
  DocumentSaved = 'DocumentSaved',          // After save
  DocumentModified = 'DocumentModified',    // After modification
  DocumentSwitched = 'DocumentSwitched',    // After switching document

  // ===== Entity Events =====
  EntityAdding = 'EntityAdding',            // Before add, cancelable
  EntityAdded = 'EntityAdded',              // After add
  EntitiesAdding = 'EntitiesAdding',        // Before batch add
  EntitiesAdded = 'EntitiesAdded',          // After batch add
  EntityModified = 'EntityModified',        // After modify
  EntityErasing = 'EntityErasing',          // Before erase, cancelable
  EntityErased = 'EntityErased',            // After erase
  EntitiesErasing = 'EntitiesErasing',      // Before batch erase
  EntitiesErased = 'EntitiesErased',        // After batch erase

  // ===== Command Events =====
  CommandStarting = 'CommandStarting',      // Before start, cancelable
  CommandStarted = 'CommandStarted',        // After start
  CommandEnded = 'CommandEnded',            // After end
  CommandCancelled = 'CommandCancelled',    // After cancel

  // ===== Layer Events =====
  LayerAdding = 'LayerAdding',              // Before add, cancelable
  LayerAdded = 'LayerAdded',                // After add
  LayerDeleting = 'LayerDeleting',          // Before delete, cancelable
  LayerDeleted = 'LayerDeleted',            // After delete
  LayerModified = 'LayerModified',          // After modify
  CurrentLayerChanged = 'CurrentLayerChanged', // Current layer changed

  // ===== Selection Events =====
  SelectionChanged = 'SelectionChanged',    // Selection changed
  SelectionCleared = 'SelectionCleared',    // Selection cleared

  // ===== View Events =====
  ViewZoomed = 'ViewZoomed',                // After zoom
  ViewPanned = 'ViewPanned',                // After pan
  ViewRegenerated = 'ViewRegenerated',      // After redraw

  // ===== Block Events =====
  BlockAdding = 'BlockAdding',              // Before add, cancelable
  BlockAdded = 'BlockAdded',                // After add
  BlockDeleting = 'BlockDeleting',          // Before delete, cancelable
  BlockDeleted = 'BlockDeleted',            // After delete
  BlockModified = 'BlockModified',          // After modify

  // ===== Collaboration and Version Control Events =====
  
  // Server sync events
  DocumentUploading = 'DocumentUploading',  // Before upload, cancelable
  DocumentUploaded = 'DocumentUploaded',    // After upload
  DocumentDownloading = 'DocumentDownloading', // Before download, cancelable
  DocumentDownloaded = 'DocumentDownloaded',   // After download
  DocumentSyncStatusChanged = 'DocumentSyncStatusChanged', // Sync status changed
  
  // Local storage events
  DocumentCaching = 'DocumentCaching',      // Before cache save, cancelable
  DocumentCached = 'DocumentCached',        // After cache save
  DocumentRestoring = 'DocumentRestoring',  // Before restore from cache, cancelable
  DocumentRestored = 'DocumentRestored',    // After restore from cache
  DocumentCacheCleared = 'DocumentCacheCleared', // After cache cleared
  
  // Branch events
  BranchCreating = 'BranchCreating',        // Before branch creation, cancelable
  BranchCreated = 'BranchCreated',          // After branch creation
  BranchSwitching = 'BranchSwitching',      // Before branch switch, cancelable
  BranchSwitched = 'BranchSwitched',        // After branch switch
  BranchMerging = 'BranchMerging',          // Before branch merge, cancelable
  BranchMerged = 'BranchMerged',            // After branch merge
  BranchDeleting = 'BranchDeleting',        // Before branch deletion, cancelable
  BranchDeleted = 'BranchDeleted',          // After branch deletion
  
  // Patch events
  PatchCreating = 'PatchCreating',          // Before patch creation, cancelable
  PatchCreated = 'PatchCreated',            // After patch creation
  PatchApplying = 'PatchApplying',          // Before patch apply, cancelable
  PatchApplied = 'PatchApplied',            // After patch apply
  PatchReverting = 'PatchReverting',        // Before patch revert, cancelable
  PatchReverted = 'PatchReverted',          // After patch revert
  
  // Conflict events
  ConflictDetected = 'ConflictDetected',    // Conflict detected
  ConflictResolving = 'ConflictResolving',  // Before conflict resolution, cancelable
  ConflictResolved = 'ConflictResolved',    // After conflict resolution
  ConflictSkipped = 'ConflictSkipped',      // Conflict skipped

  // ===== Plugin Events =====
  PluginLoading = 'PluginLoading',          // Plugin begins loading
  PluginLoaded = 'PluginLoaded',            // Plugin finished loading
  PluginActivating = 'PluginActivating',    // Plugin begins activation
  PluginActivated = 'PluginActivated',      // Plugin activation finished
  PluginDeactivating = 'PluginDeactivating', // Plugin begins deactivation
  PluginDeactivated = 'PluginDeactivated',  // Plugin deactivation finished
  PluginUnloading = 'PluginUnloading',      // Plugin begins unloading
  PluginUnloaded = 'PluginUnloaded',        // Plugin unloading finished
  PluginError = 'PluginError',              // Plugin error occurred

  // ===== Context Menu Events =====
  ContextMenuOpening = 'ContextMenuOpening',  // Before context menu opens, cancelable and customizable
  ContextMenuOpened = 'ContextMenuOpened',    // After context menu opens
  ContextMenuItemClicked = 'ContextMenuItemClicked', // Menu item clicked

  // ===== UI Events =====
  RibbonConfigChanged = 'RibbonConfigChanged' // Ribbon config changed
}

Event Categories

Document Events

Event	Description	Cancelable
`DocumentCreating`	Before creating a document	Yes
`DocumentCreated`	After creating a document	No
`DocumentOpening`	Before opening a document	Yes
`DocumentOpened`	After opening a document	No
`DocumentClosing`	Before closing a document	Yes
`DocumentClosed`	After closing a document	No
`DocumentSaving`	Before saving a document	Yes
`DocumentSaved`	After saving a document	No
`DocumentModified`	After document modification	No
`DocumentSwitched`	After switching the current document	No

Entity Events

Event	Description	Cancelable
`EntityAdding`	Before adding an entity	Yes
`EntityAdded`	After adding an entity	No
`EntitiesAdding`	Before batch adding entities	Yes
`EntitiesAdded`	After batch adding entities	No
`EntityModified`	After modifying an entity	No
`EntityErasing`	Before deleting an entity	Yes
`EntityErased`	After deleting an entity	No
`EntitiesErasing`	Before batch deleting entities	Yes
`EntitiesErased`	After batch deleting entities	No

Command Events

Event	Description	Cancelable
`CommandStarting`	Before a command starts	Yes
`CommandStarted`	After a command starts	No
`CommandEnded`	After a command ends	No
`CommandCancelled`	After a command is canceled	No

Layer Events

Event	Description	Cancelable
`LayerAdding`	Before adding a layer	Yes
`LayerAdded`	After adding a layer	No
`LayerDeleting`	Before deleting a layer	Yes
`LayerDeleted`	After deleting a layer	No
`LayerModified`	After modifying layer properties	No
`CurrentLayerChanged`	After current layer changes	No

Selection Events

Event	Description
`SelectionChanged`	After selection changes
`SelectionCleared`	After selection is cleared

`SelectionChangedEventArgs`

Property	Type	Description
`document`	`CadDocument`	Owning document
`previousSelection`	`EntityBase[]`	Previous selection set
`currentSelection`	`EntityBase[]`	Current selection set
`selections`	`EntityBase[]`	Alias of `currentSelection`
`added`	`EntityBase[]`	Newly added entities
`removed`	`EntityBase[]`	Removed entities

View Events

Event	Description
`ViewZoomed`	After view zoom
`ViewPanned`	After view pan
`ViewRegenerated`	After view redraw

Block Events

Event	Description	Cancelable
`BlockAdding`	Before adding a block definition	Yes
`BlockAdded`	After adding a block definition	No
`BlockDeleting`	Before deleting a block definition	Yes
`BlockDeleted`	After deleting a block definition	No
`BlockModified`	After modifying a block definition	No

Collaboration and Version Control Events

These events are used for collaboration, cloud synchronization, and version-management scenarios.

Server Sync Events

Event	Description	Cancelable
`DocumentUploading`	Before uploading a document to the server	Yes
`DocumentUploaded`	After uploading a document to the server	No
`DocumentDownloading`	Before downloading a document from the server	Yes
`DocumentDownloaded`	After downloading a document from the server	No
`DocumentSyncStatusChanged`	Document synchronization status changed	No

Local Storage Events

Event	Description	Cancelable
`DocumentCaching`	Before saving to local cache	Yes
`DocumentCached`	After saving to local cache	No
`DocumentRestoring`	Before restoring from local cache	Yes
`DocumentRestored`	After restoring from local cache	No
`DocumentCacheCleared`	After local cache is cleared	No

Branch Events

Event	Description	Cancelable
`BranchCreating`	Before creating a branch	Yes
`BranchCreated`	After creating a branch	No
`BranchSwitching`	Before switching branches	Yes
`BranchSwitched`	After switching branches	No
`BranchMerging`	Before merging a branch	Yes
`BranchMerged`	After merging a branch	No
`BranchDeleting`	Before deleting a branch	Yes
`BranchDeleted`	After deleting a branch	No

Patch Events

Event	Description	Cancelable
`PatchCreating`	Before creating a patch	Yes
`PatchCreated`	After creating a patch	No
`PatchApplying`	Before applying a patch	Yes
`PatchApplied`	After applying a patch	No
`PatchReverting`	Before reverting a patch	Yes
`PatchReverted`	After reverting a patch	No

Conflict Events

Event	Description	Cancelable
`ConflictDetected`	Conflict detected	No
`ConflictResolving`	Before resolving a conflict	Yes
`ConflictResolved`	After resolving a conflict	No
`ConflictSkipped`	Conflict skipped	No

Plugin Events

Event	Description
`PluginLoading`	Plugin starts loading
`PluginLoaded`	Plugin finished loading
`PluginActivating`	Plugin starts activating
`PluginActivated`	Plugin activation finished
`PluginDeactivating`	Plugin starts deactivating
`PluginDeactivated`	Plugin deactivation finished
`PluginUnloading`	Plugin starts unloading
`PluginUnloaded`	Plugin unloading finished
`PluginError`	Plugin error occurred

Event	Description	Cancelable
`ContextMenuOpening`	Before the context menu opens; menu items can be customized	Yes
`ContextMenuOpened`	After the context menu opens	No
`ContextMenuItemClicked`	Menu item was clicked	No

For detailed usage, see Context Menu.

UI Events

Event	Description
`RibbonConfigChanged`	Ribbon configuration changed; notifies RibbonBar to rerender

Event Naming Convention

WebCAD events follow these naming rules:

Before events ending with -ing: fired before an operation, usually cancelable
After events ending with -ed: fired after an operation completes and are not cancelable
Changed events: fired after a state change

// Before event example - operation can be canceled
eventManager.on(CadEvents.DocumentSaving, (args) => {
  if (!validateDocument()) {
    args.cancel = true;  // Cancel save
    Engine.writeMessage('Document validation failed. Save canceled.');
  }
});

// After event example - for notification or follow-up logic
eventManager.on(CadEvents.DocumentSaved, (args) => {
  console.log('Document saved:', args.document.name);
});

Next Steps

Event Usage - listen to and handle events