The default controller for a multi column view. Takes care of adding the MultiColumnCollectionHeader and reacting to the various callbacks.
| cellLabelUssClassName | The USS class name for default labels cells inside a multi column view. | 
| cellUssClassName | The USS class name for all cells inside a multi column view. | 
| headerContainerUssClassName | The USS class name for the header container inside a multi column view. | 
| rowContainerUssClassName | The USS class name for all row containers inside a multi column view. | 
| MultiColumnController | Constructor. It will create the MultiColumnCollectionHeader to use for the view. | 
| BindItem | Binds a row of multiple cells to an item index. | 
| DestroyItem | Destroys a VisualElement when the view is rebuilt or cleared. | 
| Dispose | Unregisters events and removes the header from the hierarchy. | 
| MakeItem | Creates a VisualElement to use in the virtualization of the collection view. It will create a cell for every visible column. | 
| PrepareView | Initialization step once the view is set. It will insert the multi column header in the hierarchy and register to important callbacks. | 
| UnbindItem | Unbinds the row at the item index. | 
| columnSortingChanged | Raised when sorting changes for a column. | 
| headerContextMenuPopulateEvent | Raised when a column is right-clicked to bring context menu options. |