请问如何给树控件(CTreeCtrl)加上背景图片？

Question

树控件过于单调，请问如何给树控件(CTreeCtrl)加上背景图片？

Answer 1

实现步骤：3.1 加入成员函数 BOOL CMyTreeCtrl::SetBKImage(LPCTSTR LpszResource)
{
if( m_bitmap.m_hObject != NULL )
m_bitmap.DeleteObject();

HBITMAP hbmp = (HBITMAP)::LoadImage(AfxGetInstanceHandle(), 
LpszResource, IMAGE_BITMAP, 0, 0, LR_CREATEDIBSECTION|LR_LOADFROMFILE); if( hbmp == NULL ) 
return FALSE; m_bitmap.Attach( hbmp );
return TRUE;
}
3.2 为WM_PAINT加入消息句柄 void CMyTreeCtrl::OnPaint() 
{
CPaintDC dc(this);

CRect rcclient;
GetClientRect(&rcclient); CDC memdc;
memdc.CreateCompatibleDC(&dc);
CBitmap bitmap;
bitmap.CreateCompatibleBitmap(&dc, rcclient.Width(), rcclient.Height());
memdc.SelectObject( &bitmap ); CWnd::DefWindowProc(WM_PAINT, (WPARAM)memdc.m_hDC , 0); CDC maskdc;
maskdc.CreateCompatibleDC(&dc);
CBitmap maskbitmap;
maskbitmap.CreateBitmap(rcclient.Width(), rcclient.Height(), 1, 1, NULL);
maskdc.SelectObject( &maskbitmap );
maskdc.BitBlt( 0, 0, rcclient.Width(), rcclient.Height(), &memdc, 
rcclient.left, rcclient.top, SRCCOPY); CBrush brush;
brush.CreatePatternBrush(&m_bitmap);
dc.FillRect(rcclient, &brush);

memdc.SetBkColor(RGB(0,0,0));          
memdc.SetTextColor(RGB(255,255,255));  
memdc.BitBlt(rcclient.left, rcclient.top, rcclient.Width(), rcclient.Height(),
                &maskdc, rcclient.left, rcclient.top, SRCAND); dc.SetBkColor(RGB(255,255,255));
dc.SetTextColor(RGB(0,0,0));
dc.BitBlt(rcclient.left, rcclient.top, rcclient.Width(), rcclient.Height(), 
             &maskdc, rcclient.left, rcclient.top, SRCAND);

dc.BitBlt(rcclient.left, rcclient.top, rcclient.Width(), rcclient.Height(), 
             &memdc, rcclient.left, rcclient.top,SRCPAINT);
brush.DeleteObject();
}
3.3 处理tvn_itemexpanding void CMyTreeCtrl::OnItemexpanding(NMHDR* pNMHDR, LRESULT* pResult) 
{
NM_TREEVIEW* pNMTreeView = (NM_TREEVIEW*)pNMHDR;
SetRedraw(FALSE);
*pResult = 0;
}
3.4 处理tvn_itemexpanded void CMyTreeCtrl::OnItemexpanded(NMHDR* pNMHDR, LRESULT* pResult) 
{
NM_TREEVIEW* pNMTreeView = (NM_TREEVIEW*)pNMHDR;
Invalidate();
SetRedraw(TRUE);
*pResult = 0;
}
3.5 加入WM_ERASEBKGND消息处理函数既然我们在OnPaint()函数中处理位图并返回TRUE以保证默认的窗口进程不擦除背景，加入这个消息句柄可以避免额外的对客户区的刷新以减少闪烁。 BOOL CMyTreeCtrl::OnEraseBkgnd(CDC* pDC) 
{
return TRUE;
}