Method _open

src/cdk/menu/context-menu-trigger.ts:210–238

* Open the attached menu at the specified location. * @param userEvent User-generated event that opened the menu * @param coordinates where to open the context menu

(userEvent: MouseEvent | null, coordinates: ContextMenuCoordinates)

   * @param coordinates where to open the context menu
   */
  private _open(userEvent: MouseEvent | null, coordinates: ContextMenuCoordinates) {
    if (this.disabled) {
      return;
    }
    if (this.isOpen()) {
      // since we're moving this menu we need to close any submenus first otherwise they end up
      // disconnected from this one.
      this.menuStack.closeSubMenuOf(this.childMenu!);

      (
        this.overlayRef!.getConfig().positionStrategy as FlexibleConnectedPositionStrategy
      ).setOrigin(coordinates);
      this.overlayRef!.updatePosition();
    } else {
      this.opened.next();

      if (this.overlayRef) {
        (
          this.overlayRef.getConfig().positionStrategy as FlexibleConnectedPositionStrategy
        ).setOrigin(coordinates);
        this.overlayRef.updatePosition();
      } else {
        this.overlayRef = createOverlayRef(this._injector, this._getOverlayConfig(coordinates));
      }

      this.overlayRef.attach(this.getMenuContentPortal());
      this._subscribeToOutsideClicks(userEvent);
    }
  }
}