Windows Dev Intro - How to avoid TVN_SELCHANGED not captured

最新推荐文章于 2020-04-10 13:21:05 发布

fanbird2008

最新推荐文章于 2020-04-10 13:21:05 发布

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分类专栏： OS/Win

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本文介绍在Visual Studio中处理TreeView控件的通知消息，特别是在多字节和Unicode版本间的区别。通过示例代码展示了如何安全地处理不同编码环境下TVN_SELCHANGING和TVN_SELCHANGED等消息。

摘要生成于 C知道，由 DeepSeek-R1 满血版支持，前往体验 >

1. include commctl.h

#define TVN_SELCHANGINGA        (TVN_FIRST-1)
#define TVN_SELCHANGINGW        (TVN_FIRST-50)
#define TVN_SELCHANGEDA         (TVN_FIRST-2)
#define TVN_SELCHANGEDW         (TVN_FIRST-51)

ifdef UNICODE
#define TVN_SELCHANGING         TVN_SELCHANGINGW
#define TVN_SELCHANGED          TVN_SELCHANGEDW
#define TVN_GETDISPINFO         TVN_GETDISPINFOW
#define TVN_SETDISPINFO         TVN_SETDISPINFOW
#define TVN_ITEMEXPANDING       TVN_ITEMEXPANDINGW
#define TVN_ITEMEXPANDED        TVN_ITEMEXPANDEDW
#define TVN_BEGINDRAG           TVN_BEGINDRAGW
#define TVN_BEGINRDRAG          TVN_BEGINRDRAGW
#define TVN_DELETEITEM          TVN_DELETEITEMW
#define TVN_BEGINLABELEDIT      TVN_BEGINLABELEDITW
#define TVN_ENDLABELEDIT        TVN_ENDLABELEDITW
#else
#define TVN_SELCHANGING         TVN_SELCHANGINGA
#define TVN_SELCHANGED          TVN_SELCHANGEDA
#define TVN_GETDISPINFO         TVN_GETDISPINFOA
#define TVN_SETDISPINFO         TVN_SETDISPINFOA
#define TVN_ITEMEXPANDING       TVN_ITEMEXPANDINGA
#define TVN_ITEMEXPANDED        TVN_ITEMEXPANDEDA
#define TVN_BEGINDRAG           TVN_BEGINDRAGA
#define TVN_BEGINRDRAG          TVN_BEGINRDRAGA
#define TVN_DELETEITEM          TVN_DELETEITEMA
#define TVN_BEGINLABELEDIT      TVN_BEGINLABELEDITA
#define TVN_ENDLABELEDIT        TVN_ENDLABELEDITA
#endif

2. in visual studio window project

as far as multibyte version and unicode version, TVN_SELCHANGED

is mapped to different value, multibyte mapped to TVN_SELCHANGEDA (TVN_FIRST-2),

but unicode version mapped to TVN_SELCHANGEDW (TVN_FIRST-51)

Therefore care need be taked here.

3. Safe Solutions.

LRESULT DialogWindow::OnTreeNotify(LPNMHDR lp)
{
HWND hTree = lp->hwndFrom;
TRACE("notify code = 0x%X (%d)\n", lp->code, lp->code);
switch (lp->code) {
#if 0
case NM_CLICK:
{
      return OnTreeClicked(lp);
}
case NM_DBLCLK:
{
     return OnTreeDoubleClicked(lp);
}
#endif
case TVN_SELCHANGINGA:
case TVN_SELCHANGINGW:
{
         return FALSE;
}
case TVN_SELCHANGEDA:
case TVN_SELCHANGEDW:
{
        return OnTreeSelChanged(lp);
}
default:
  break;
}

return TRUE;
}