Visual C++ 自定义的绘图技术问题？

Question

CDDS_PREPAINT 
CDDS_ITEM 
CDDS_ITEMPREPAINT 
CDDS_ITEMPOSTPAINT 
CDDS_ITEMPREERASE 
CDDS_ITEMPOSTERASE 
CDDS_SUBITEM 
CDDS_POSTPAINT 
CDDS_PREERASE 
CDDS_POSTERASE 
请高手解释一下上述的含义？

Answer 1

到MSDN上查tagNMCUSTOMDRAWINFO结构定义：
NMCUSTOMDRAW Structure--------------------------------------------------------------------------------Contains information specific to an NM_CUSTOMDRAW notification message.Syntaxtypedef struct tagNMCUSTOMDRAWINFO {
    NMHDR hdr;
    DWORD dwDrawStage;
    HDC hdc;
    RECT rc;
    DWORD_PTR dwItemSpec;
    UINT uItemState;
    LPARAM lItemlParam;
} NMCUSTOMDRAW, *LPNMCUSTOMDRAW;
Membershdr
NMHDR structure that contains information about this notification message. 
dwDrawStage
Current drawing stage. This value is one of the following. 
Global Values:
CDDS_POSTERASE
After the erasing cycle is complete.
CDDS_POSTPAINT
After the painting cycle is complete.
CDDS_PREERASE
Before the erasing cycle begins.
CDDS_PREPAINT
Before the painting cycle begins.
Item-specific Values:
CDDS_ITEM
Indicates that the dwItemSpec, uItemState, and lItemlParam members are valid.
CDDS_ITEMPOSTERASE
After an item has been erased.
CDDS_ITEMPOSTPAINT
After an item has been drawn.
CDDS_ITEMPREERASE
Before an item is erased.
CDDS_ITEMPREPAINT
Before an item is drawn.
CDDS_SUBITEM
Version 4.71. Flag combined with CDDS_ITEMPREPAINT or CDDS_ITEMPOSTPAINT if a subitem is being drawn. This will only be set if CDRF_NOTIFYITEMDRAW is returned from CDDS_PREPAINT.