The DDX_Scroll function manages the transfer of int data between a scroll-bar control in a dialog box, form view, or control view object and an int data member of the dialog box, form view, or control view object.
void AFXAPI DDX_Scroll( CDataExchange* pDX, int nIDC, int& value );
A pointer to a CDataExchange object. The framework supplies this object to establish the context of the data exchange, including its direction.
The resource ID of the scroll-bar control associated with the control property.
A reference to a member variable of the dialog box, form view or control view object with which data is exchanged.
When DDX_Scroll is called, value is set to the current position of the control's thumb. For more information on the values associated with the current position of the control's thumb, see GetScrollPos in the Windows SDK.
For more information about DDX, see Dialog Data Exchange and Validation.