如何覆盖BS_SPLITBUTTON按钮的DrawItem [英] How do I override DrawItem for BS_SPLITBUTTON buttons

问题描述

如果我创建一个新的按钮类继承自 CButton ，指定 BS_OWNERDRAW 样式，并覆盖 DrawItem 方法我可以控制按钮的呈现，如下所示：

  void CMyButton :: DrawItem（LPDRAWITEMSTRUCT lpDrawItemStruct）{
 CDC dc; 
 dc.Attach（lpDrawItemStruct-> hDC）; 
 RECT rect = lpDrawItemStruct-> rcItem; 
 dc.FillSolidRect（& rect，RGB（0，0xFF，0））; 
 dc.Detach（）; 
} 
 
 m_button.Create（LFoo，WS_CHILD | WS_VISIBLE | BS_OWNERDRAW，CRect（0，150，100，200），this，IDC_FOO）; 
  

我得到下面的结果：

这是我所希望的对于。然而，如果我继承我从CSplitButton，添加 BS_SPLITBUTTON 样式的按钮，我得到以下结果：

这是不是我希望的结果（我希望它看起来与 CButton 完全相同）。在这种情况下， DrawItem 方法没有被调用，所以我猜测 BS_SPLITBUTTONS p>

如何获得我想要的结果，一个带有自定义绘图的按钮分割按钮？

解决方案

因为它在MSDN 中为 BS_OWNERDRAW 说：

创建自绘图形按钮。当按钮的视觉方面已经改变时，所有者窗口接收到WM_DRAWITEM
消息。 不要
将BS_OWNERDRAW样式与任何其他按钮样式组合

。

。

如果你自己绘制图形，你必须自己做 。

If I make a new button class inheriting from CButton, specifying the BS_OWNERDRAW style , and overriding the DrawItem method I can control the rendering of the button, like this:

void CMyButton::DrawItem(LPDRAWITEMSTRUCT lpDrawItemStruct) {
    CDC dc;
    dc.Attach(lpDrawItemStruct->hDC);
    RECT rect = lpDrawItemStruct->rcItem;
    dc.FillSolidRect(&rect, RGB(0, 0xFF, 0));
    dc.Detach();
}

m_button.Create(L"Foo", WS_CHILD | WS_VISIBLE | BS_OWNERDRAW, CRect(0, 150, 100, 200), this, IDC_FOO);

I get the following result:

which is what I hoped for. However if I instead inherit my button from CSplitButton, which adds the BS_SPLITBUTTON style, I get the following result:

which is not the result I had hoped for (I had hoped it would look exactly the same as the CButton). The DrawItem method isn't being called in this case so I guess BS_SPLITBUTTONS are treated differently by the system.

How can I get the result I want, a button with split button behaviour with customized drawing?

解决方案

As it says in MSDN for BS_OWNERDRAW:

Creates an owner-drawn button. The owner window receives a WM_DRAWITEM message when a visual aspect of the button has changed. Do not combine the BS_OWNERDRAW style with any other button styles.

(My emphasis).

If you're doing your own drawing, you have to do all of it yourself.

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