今天從CButton派生了一個類CUIButton,主要用于自繪,按照基本的流程,重寫DrawItem方法。
步驟如下:點擊CUIButton按鈕,在右鍵彈出菜單中選擇“add windows message Handler",
找到DrawItem,為其添加消息映射,添加的代碼如下:
void CUIButton::OnDrawItem(int nIDCtl, LPDRAWITEMSTRUCT lpDrawItemStruct)
結果在使用到CUIButton的地方用SubClassDlgItem就會出問題。
后來調試發(fā)現(xiàn),不應該按照上面的添加此消息的映射,而是為CUIButton類重寫DrawItem函數(shù),添
加方法:
在類CUIButton右鍵,在彈出菜單中選擇"Add Virtual Function",彈出的添加虛函數(shù)框中選
擇"DrawItem",向導為我們生成的代碼如下:
void CUIButton::DrawItem(LPDRAWITEMSTRUCT lpDrawItemStruct)
在這里添加所需的自繪代碼就ok了
附: how to implement control to self-draw
1、從CButton類派生自己的CUIControl類
2、借助于MFC向導生成工具,為期添加虛函數(shù)DrawItem()和OnEraseBkgnd()。
注意:DrawItem()是控件重定義的函數(shù),不是OnDrawItem()。
3、在DrawItem()中近控件的自繪處理,這里給出一個實例代碼,用于一個自定義Button,在
Button上面繪圖:
void CUIButton::DrawItem(LPDRAWITEMSTRUCT lpDrawItemStruct) int nCxIcon = ::GetSystemMetrics(SM_CXICON); HICON hIcon = AfxGetApp()->LoadIcon(IDR_MAINFRAME); CRect rcClient; // draw border around icon //pDC->StretchBlt(0,0,80,80,&dcMem,0,0,nCxIcon,nCyIcon,SRCCOPY); } 4、為OnEraseBkGround()添加代碼。這里很簡單,直接返回True即可: BOOL CUIButton::OnEraseBkgnd(CDC* pDC) 5、在你的對話框中使用CUIButton按鈕,首先在dialog資源中添加一個按鈕(CButton)。 6、在對話框類的頭文件中定義一個成員CUIButton m_CtlUIBtn;注意變量的類型是CUIButton而 不是CButton 7 、在OnInitDialog中用SubClass技術: BOOL CAboutDlg::OnInitDialog() that is OK!
{
// TODO: Add your message handler code here and/or call default
//CButton::OnDrawItem(nIDCtl, lpDrawItemStruct);
int nCyIcon = ::GetSystemMetrics(SM_CYICON);
CDC *pDC = CDC::FromHandle(lpDrawItemStruct->hDC);
CBitmap bitmap;
bitmap.CreateCompatibleBitmap(pDC,nCxIcon,nCyIcon);
CDC dcMem;
dcMem.CreateCompatibleDC(pDC);
CBitmap *pOldBitmap = (CBitmap *)dcMem.SelectObject(bitmap);
ASSERT(pOldBitmap);
ASSERT(hIcon);
GetClientRect(&rcClient); // get the button's rect
dcMem.StretchBlt(0,0,nCxIcon,nCyIcon,pDC,2,2,rcClient.Width() - CX_SHADOW - 4,
rcClient.Height() - CY_SHADOW - 4,SRCCOPY);
dcMem.DrawIcon(0,0,hIcon);
CPen pen;
pen.CreateStockObject(BLACK_PEN);
ASSERT(pDC != NULL);
CPen* pPenOld = pDC->SelectObject(&pen);
pDC->Rectangle(0, 0, rcClient.Width()-CX_SHADOW, rcClient.Height()-CY_SHADOW);
if (pPenOld)
pDC->SelectObject(pPenOld);
pDC->StretchBlt(2,2,rcClient.Width() - CX_SHADOW - 4,rcClient.Height() - CY_SHADOW - 4,&dcMem,0,0,nCxIcon,nCyIcon,SRCCOPY);
{
// TODO: Add your message handler code here and/or call default
return TRUE;
//return CButton::OnEraseBkgnd(pDC);
}
{
CDialog::OnInitDialog();
m_CtlUIButton.SubclassDlgItem(IDC_UI_BUTTON,this);
return TRUE; // return TRUE unless you set the focus to a control
// EXCEPTION: OCX Property Pages should return FALSE
}