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 | virtual | 
Called by the framework when it needs to compare two list control items.
Indicates the relative position of the two items. It may be any of the following values:
The default implementation always returns 0. You have to override this function in your CBCGListCtrl - derived class to provide your own compare algorithm.
| lParam1 | Points to the first item to compare. | 
| lParam2 | Points to a second item to compare. | 
| iColumn | A zero-based index of the list control column that is being sorted. |