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。
由于我找不到一个好的示例，因此我提供了完整的代码（在我自己的解决方案中，我已将所有者绘制的控件封装到他们自己的类中，因此您需要提供一些详细信息，例如按钮是否被选中）
这是单选按钮的创建（将其添加到父窗口），同时设置 GWL_UserData 和子类化单选按钮：
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);
由于是所有者绘制，我们需要在父窗口过程中处理 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;
}
这里是 DrawControl 方法 - 它可以访问类级别的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);
}
}
接下来是用于子类化单选按钮控件的窗口过程 - 这个
使用所有 Windows 消息调用并处理几个，然后传递未处理
那些在默认的proc上。
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，使父级无效可以使绘图 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摆脱困境，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);
}
为了简单的事情需要大量的代码和努力 - 在背景图像上绘制一个主题单选按钮。希望答案能减轻其他人的痛苦！
* 对此的一大警告是，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件时才需要它。