public void OnClick() { try { m_Map = m_hookHelper.FocusMap; m_activeView = m_Map as IActiveView; m_EngineEditor = MapManager.EngineEditor; EditVertexClass.ClearResource(); if (m_EngineEditor == null) { return; } if (m_EngineEditor.EditState != esriEngineEditState.esriEngineStateEditing) { return; } IWorkspaceEdit2 pWSEdit = m_EngineEditor.EditWorkspace as IWorkspaceEdit2; if (pWSEdit == null) { return; } Boolean bHasUndo = false; pWSEdit.HasUndos(ref bHasUndo); if (bHasUndo) { pWSEdit.UndoEditOperation(); } m_activeView.Refresh(); } catch (Exception ex) { } }