CWnd::ScrollWindow

  • 项目

voidScrollWindow(intxAmount**,intyAmount,LPCRECTlpRect=NULL,LPCRECTlpClipRect=NULL);**

Parameters

xAmount

Specifies the amount, in device units, of horizontal scrolling. This parameter must be a negative value to scroll to the left.

yAmount

Specifies the amount, in device units, of vertical scrolling. This parameter must be a negative value to scroll up.

lpRect

Points to a CRect object or RECT structure that specifies the portion of the client area to be scrolled. If lpRect is NULL, the entire client area is scrolled. The caret is repositioned if the cursor rectangle intersects the scroll rectangle.

lpClipRect

Points to a CRect object or RECT structure that specifies the clipping rectangle to scroll. Only bits inside this rectangle are scrolled. Bits outside this rectangle are not affected even if they are in the lpRect rectangle. If lpClipRect is NULL, no clipping is performed on the scroll rectangle.

Remarks

Scrolls the contents of the client area of the current CWnd object.

If the caret is in the CWnd being scrolled, ScrollWindow automatically hides the caret to prevent it from being erased and then restores the caret after the scroll is finished. The caret position is adjusted accordingly.

The area uncovered by the ScrollWindow member function is not repainted but is combined into the current CWnd object’s update region. The application will eventually receive a message notifying it that the region needs repainting. To repaint the uncovered area at the same time the scrolling is done, call the UpdateWindow member function immediately after calling ScrollWindow.

If lpRect is NULL, the positions of any child windows in the window are offset by the amount specified by xAmount and yAmount, and any invalid (unpainted) areas in the CWnd are also offset. ScrollWindow is faster when lpRect is NULL.

If lpRect is not NULL, the positions of child windows are not changed, and invalid areas in CWnd are not offset. To prevent updating problems when lpRect is not NULL, call the UpdateWindow member function to repaint CWnd before calling ScrollWindow.

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See Also   CWnd::UpdateWindow,