在断断续续地观察了近三个月后，我终于找到了一个令我满意的解决方案。我最终发现单选按钮边缘由于某种原因没有被 WM_DRAWITEM 中的例程绘制，但是如果我在控件周围的矩形中使单选按钮控件的父级无效，它们就会出现。
因为我找不到一个好的例子，所以我提供了完整的代码（在我自己的解决方案中，我已经将我的所有者绘制的控件封装到他们自己的类中，所以你需要提供一些细节，例如按钮是否被选中或不）
这是单选按钮的创建（将其添加到父窗口）也设置 GWL_UserData 和子类单选按钮：
HWND hWndControl = CreateWindow( _T("BUTTON"), caption, WS_CHILD | WS_VISIBLE | BS_OWNERDRAW,
xPos, yPos, width, height, parentHwnd, (HMENU) id, NULL, NULL);
// Using SetWindowLong and GWL_USERDATA I pass in the this reference, allowing my
// window proc toknow about the control state such as if it is selected
SetWindowLong( hWndControl, GWL_USERDATA, (LONG)this);
// And subclass the control - the WndProc is shown later
SetWindowSubclass(hWndControl, OwnerDrawControl::WndProc, 0, 0);
由于它是所有者绘制，我们需要在父窗口 proc 中处理 WM_DRAWITEM 消息。
case WM_DRAWITEM:
{
LPDRAWITEMSTRUCT pDIS = (LPDRAWITEMSTRUCT)lParam;
hTheme = OpenThemeData(hDlg, L"BUTTON");
HDC dc = pDIS->hDC;
wchar_t sCaption[100];
GetWindowText(GetDlgItem(hDlg, pDIS->CtlID), sCaption, 100);
std::wstring staticText(sCaption);
// Controller here passes to a class that holds a map of all controls
// which then passes on to the correct instance of my owner draw class
// which has the drawing code I show below
controller->DrawControl(pDIS->hwndItem, hTheme, dc, pDIS->rcItem,
staticText, pDIS->CtlID, pDIS->itemState, pDIS->itemAction);
SetBkMode(dc, TRANSPARENT);
SetTextColor(hdcStatic, RGB(0,0,0));
CloseThemeData(hTheme);
return TRUE;
}
这是 DrawControl 方法 - 它可以访问类级变量以允许管理状态，因为所有者绘制不会自动处理。
void OwnerDrawControl::DrawControl(HWND hwnd, HTHEME hTheme, HDC dc, bool checked, RECT rcItem, std::wstring caption, int ctrlId, UINT item_state, UINT item_action)
{
// Check if we need to draw themed data
if (hTheme)
{
HWND parent = GetParent(hwnd);
static const int cb_size = 13;
RECT bgRect, textRect;
HFONT font = (HFONT)SendMessageW(hwnd, WM_GETFONT, 0, 0);
DWORD state;
// This method handles both radio buttons and checkboxes - the enums here
// are part of my own code, not Windows enums.
// We also have hot tracking - this is shown in the window subclass later
if (Type() == RADIO_BUTTON)
state = ((checked) ? RBS_CHECKEDNORMAL : RBS_UNCHECKEDNORMAL) | ((is_hot_) ? RBS_HOT : 0);
else if (Type() == CHECK_BOX)
state = ((checked) ? CBS_CHECKEDNORMAL : CBS_UNCHECKEDNORMAL) | ((is_hot_) ? RBS_HOT : 0);
GetClientRect(hwnd, &bgRect);
// the theme type is either BP_RADIOBUTTON or BP_CHECKBOX where these are Windows enums
DWORD theme_type = ThemeType();
GetThemeBackgroundContentRect(hTheme, dc, theme_type, state, &bgRect, &textRect);
DWORD dtFlags = DT_VCENTER | DT_SINGLELINE;
if (dtFlags & DT_SINGLELINE) /* Center the checkbox / radio button to the text. */
bgRect.top = bgRect.top + (textRect.bottom - textRect.top - cb_size) / 2;
/* adjust for the check/radio marker */
// The +3 and +6 are a slight fudge to allow the focus rectangle to show correctly
bgRect.bottom = bgRect.top + cb_size;
bgRect.left += 3;
bgRect.right = bgRect.left + cb_size;
textRect.left = bgRect.right + 6;
DrawThemeBackground(hTheme, dc, theme_type, state, &bgRect, NULL);
DrawThemeText(hTheme, dc, theme_type, state, caption.c_str(), lstrlenW(caption.c_str()), dtFlags, 0, &textRect);
// Draw Focus Rectangle - I still don't really like this, it draw on the parent
// mainly to work around the way DrawFocus toggles the focus rect on and off.
// That coupled with some of my other drawing meant this was the only way I found
// to get a reliable focus effect.
BOOL bODAEntire = (item_action & ODA_DRAWENTIRE);
BOOL bIsFocused = (item_state & ODS_FOCUS);
BOOL bDrawFocusRect = !(item_state & ODS_NOFOCUSRECT);
if (bIsFocused && bDrawFocusRect)
{
if ((!bODAEntire))
{
HDC pdc = GetDC(parent);
RECT prc = GetMappedRectanglePos(hwnd, parent);
DrawFocus(pdc, prc);
}
}
}
// This handles drawing when we don't have themes
else
{
TEXTMETRIC tm;
GetTextMetrics(dc, &tm);
RECT rect = { rcItem.left ,
rcItem.top ,
rcItem.left + tm.tmHeight - 1,
rcItem.top + tm.tmHeight - 1};
DWORD state = ((checked) ? DFCS_CHECKED : 0 );
if (Type() == RADIO_BUTTON)
DrawFrameControl(dc, &rect, DFC_BUTTON, DFCS_BUTTONRADIO | state);
else if (Type() == CHECK_BOX)
DrawFrameControl(dc, &rect, DFC_BUTTON, DFCS_BUTTONCHECK | state);
RECT textRect = rcItem;
textRect.left = rcItem.left + 19;
SetTextColor(dc, ::GetSysColor(COLOR_BTNTEXT));
SetBkColor(dc, ::GetSysColor(COLOR_BTNFACE));
DrawText(dc, caption.c_str(), -1, &textRect, DT_WORDBREAK | DT_TOP);
}
}
接下来是用于对单选按钮控件进行子类化的窗口 proc - 它使用所有窗口消息调用并处理几个，然后将未处理的消息传递给默认 proc。
LRESULT OwnerDrawControl::WndProc(HWND hWnd, UINT uMsg, WPARAM wParam,
LPARAM lParam, UINT_PTR uIdSubclass, DWORD_PTR dwRefData)
{
// Get the button parent window
HWND parent = GetParent(hWnd);
// The page controller and the OwnerDrawControl hold some information we need to draw
// correctly, such as if the control is already set hot.
st_mini::IPageController * controller = GetWinLong<st_mini::IPageController *> (parent);
// Get the control
OwnerDrawControl *ctrl = (OwnerDrawControl*)GetWindowLong(hWnd, GWL_USERDATA);
switch (uMsg)
{
case WM_LBUTTONDOWN:
if (controller)
{
int ctrlId = GetDlgCtrlID(hWnd);
// OnCommand is where the logic for things like selecting a radiobutton
// and deselecting the rest of the group lives.
// We also call our Invalidate method there, which redraws the radio when
// it is selected. The Invalidate method will be shown last.
controller->OnCommand(parent, ctrlId, 0);
return (0);
}
break;
case WM_LBUTTONDBLCLK:
// We just treat doubleclicks as clicks
PostMessage(hWnd, WM_LBUTTONDOWN, wParam, lParam);
break;
case WM_MOUSEMOVE:
{
if (controller)
{
// This is our hot tracking allowing us to paint the control
// correctly when the mouse is over it - it sets flags that get
// used by the above DrawControl method
if(!ctrl->IsHot())
{
ctrl->SetHot(true);
// We invalidate to repaint
ctrl->InvalidateControl();
// Track the mouse event - without this the mouse leave message is not sent
TRACKMOUSEEVENT tme;
tme.cbSize = sizeof(TRACKMOUSEEVENT);
tme.dwFlags = TME_LEAVE;
tme.hwndTrack = hWnd;
TrackMouseEvent(&tme);
}
}
return (0);
}
break;
case WM_MOUSELEAVE:
{
if (controller)
{
// Turn off the hot display on the radio
if(ctrl->IsHot())
{
ctrl->SetHot(false);
ctrl->InvalidateControl();
}
}
return (0);
}
case WM_SETFOCUS:
{
ctrl->InvalidateControl();
}
case WM_KILLFOCUS:
{
RECT rcItem;
GetClientRect(hWnd, &rcItem);
HDC dc = GetDC(parent);
RECT prc = GetMappedRectanglePos(hWnd, parent);
DrawFocus(dc, prc);
return (0);
}
case WM_ERASEBKGND:
return 1;
}
// Any messages we don't process must be passed onto the original window function
return DefSubclassProc(hWnd, uMsg, wParam, lParam);
}
最后一个难题是您需要在正确的时间使控件无效（重绘它）。我最终发现，使父级无效可以让绘图 100% 正确工作。这导致了闪烁，直到我意识到我可以通过仅使与单选检查一样大的矩形无效来逃脱，而不是像我以前那样大到包括文本在内的整个控件。
void InvalidateControl()
{
// GetMappedRectanglePos is my own helper that uses MapWindowPoints
// to take a child control and map it to its parent
RECT rc = GetMappedRectanglePos(ctrl_, parent_);
// This was my first go, that caused flicker
// InvalidateRect(parent_, &rc_, FALSE);
// Now I invalidate a smaller rectangle
rc.right = rc.left + 13;
InvalidateRect(parent_, &rc, FALSE);
}
很多代码和工作都应该很简单——在背景图像上绘制一个主题单选按钮。希望答案可以减轻其他人的痛苦！
*一个重要的警告是，它仅适用于背景上的所有者控件（例如填充矩形或图像）100% 正确。不过没关系，因为只有在背景上绘制无线电控制时才需要它。