hDlg
[in] Handle to the dialog box that contains the control.
nIDDlgItem
[in] Specifies the identifier of the control that receives the message.
Msg
[in] Specifies the message to be sent.
wParam
[in] Specifies additional message-specific information.
lParam
[in] Specifies additional message-specific information.
Return Value
The return value specifies the result of the message processing and depends on the message sent.