MMCN_COLUMN_CLICK
[This is pr69eliminary documentation and subject to change.] 
Sent when the user clicks on a result-list view column header.
Parameters
- 
pDataobject
- 
NULL.
- 
arg
- 
Column number.
- 
param 
- 
Sort option flags. By default, the sort is in ascending order. To specify descending order, use the RSI_DESCENDING (0x0001) flag. 
Return Values
Not used.