How to set up the drawing area in the click function by Mfc

I know that there is an InvalidateRect setting area in onpaint, but if you can only draw on CClientDC directly when clicking on the function, how to set the drawing update area

Jun.18,2021
MySQL Query : SELECT * FROM `codeshelper`.`v9_news` WHERE status=99 AND catid='6' ORDER BY rand() LIMIT 5
MySQL Error : Disk full (/tmp/#sql-temptable-64f5-1b38413-2c116.MAI); waiting for someone to free some space... (errno: 28 "No space left on device")
MySQL Errno : 1021
Message : Disk full (/tmp/#sql-temptable-64f5-1b38413-2c116.MAI); waiting for someone to free some space... (errno: 28 "No space left on device")
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