'trackbar position
' 设置跟踪条滑块的当前的逻辑位置。
'  hTrackbar : The handle of the track bar. (e.g. HWND_FORM1_SLIDER1)
'  fPosition : Redraw flag. If this parameter is TRUE, the message redraws the 
'              control with the slider at the position given by lPosition. If this parameter 
'              is FALSE, the message does not redraw the slider at the new position. Note that 
'              the message sets the value of the slider position (as returned by the TBM_GETPOS message) 
'              regardless of the fPosition parameter.
'  lPosition : New logical position of the slider. Valid logical positions are 
'              the integer values in the trackbar's range of minimum to maximum slider positions. 
'              If this value is outside the control's maximum and minimum range, the position is 
'              set to the maximum or minimum value.
Sub FF_TrackBar_SetPos (ByVal hTrackbar As HWND, ByVal fPosition As Long, ByVal lPosition As Long)

    SendMessage hTrackbar, TBM_SETPOS, fPosition, lPosition

End Sub
