Manual Invalidation
Manual Invalidation
The Tree List automatically repaints its elements after their appearance or display information has been changed. For instance, the footer panel is automatically repainted after its appearance settings have been changed or its summary values have been updated. In some cases, however, you do need to manually invalidate elements. For instance, the summary footer is not repainted when the selection changes. So, you need to invalidate the summary footer manually, if you want to display the number of selected nodes in it.
To force invalidation manually, you will need to call the invalidation methods designed for this purpose. All such methods add the corresponding region to the control’s update region that will be repainted during the next paint operation. To force a synchronous paint, you should call the Tree List’s Update method after calling an invalidation method. These methods are listed in the table below.
| Name | Description |
|---|---|
| TreeList.InvalidateCell | Invalidates the specified cell. |
| TreeList.InvalidateColumnHeader | Invalidates the header of the specified column. |
| TreeList.InvalidateColumnPanel | Invalidates the column header panel. |
| TreeList.InvalidateNode | Invalidates the specified node. |
| TreeList.InvalidateNodes | Invalidates all the visible nodes and row footers. |
| TreeList.InvalidateSummaryFooterPanel | Invalidates the summary footer panel. |