当使用 \foreach 时，mdframed 会从描述环境中吞噬项目标签

Question

以下工作：

1. description在mdframed。
2. foreach在description。

但是在标签 的环境中foreach使用时会出现一些奇怪的行为descriptionmdframed\item第一个之后 \item被狼吞虎咽：

\listfiles：

article.cls        2014/09/29 v1.4h Standard LaTeX document class
size10.clo         2014/09/29 v1.4h Standard LaTeX file (size option)
xcolor.sty         2007/01/21 v2.11 LaTeX color extensions (UK)
color.cfg          2007/01/18 v1.5 color configuration of teTeX/TeXLive
xetex.def          2014/07/25 v4.03 LaTeX color/graphics driver for XeTeX (RRM/JK)

mdframed.sty       2013/07/01 1.9b: mdframed

kvoptions.sty      2011/06/30 v3.11 Key value format for package options (HO)
keyval.sty         2014/10/28 v1.15 key=value parser (DPC)
ltxcmds.sty        2011/11/09 v1.22 LaTeX kernel commands for general use (HO)
kvsetkeys.sty      2012/04/25 v1.16 Key value parser (HO)
infwarerr.sty      2010/04/08 v1.3 Providing info/warning/error messages (HO)
etexcmds.sty       2011/02/16 v1.5 Avoid name clashes with e-TeX commands (HO)
ifluatex.sty       2010/03/01 v1.3 Provides the ifluatex switch (HO)
xparse.sty         2014/11/25 v5471 L3 Experimental document command parser
expl3.sty          2014/11/25 v5471 L3 programming layer (loader) 
expl3-code.tex     2014/11/25 v5471 L3 programming layer 
etex.sty           1998/03/26 v2.0 eTeX basic definition package (PEB)
l3unicode-data.def 2014/11/23 v5465 L3 Unicode data
l3xdvipdfmx.def    
etoolbox.sty       2011/01/03 v2.1 e-TeX tools for LaTeX
zref-abspage.sty   2012/04/04 v2.24 Module abspage for zref (HO)
zref-base.sty      2012/04/04 v2.24 Module base for zref (HO)
kvdefinekeys.sty   2011/04/07 v1.3 Define keys (HO)
pdftexcmds.sty     2011/11/29 v0.20 Utility functions of pdfTeX for LuaTeX (HO)
ifpdf.sty          2011/01/30 v2.3 Provides the ifpdf switch (HO)
auxhook.sty        2011/03/04 v1.3 Hooks for auxiliary files (HO)
atbegshi.sty       2011/10/05 v1.16 At begin shipout hook (HO)
needspace.sty      2010/09/12 v1.3d reserve vertical space
md-frame-0.mdf     2013/07/01\ 1.9b: md-frame-0
pgffor.sty         2013/12/13 v3.0.0 (rcs-revision 1.25)
pgfrcs.sty         2013/12/20 v3.0.0 (rcs-revision 1.28)
everyshi.sty       2001/05/15 v3.00 EveryShipout Package (MS)

代码：

\documentclass{article}
\usepackage{xcolor}
\usepackage{mdframed}
\usepackage{pgffor}

\newcommand*{\MyForEachLoop}{%
    \foreach \x/\y in {
            First/{item A in list}, 
            Second/{item B in list}, 
            Third/{item C in list}} {%
        \item [\x] \y.
    }%
}

\mdfsetup{frametitlerule=true}

\listfiles
\begin{document}
\begin{mdframed}[backgroundcolor=green!25, frametitle={description in mdframed (works):}]
    \begin{description}
        \item [First]  item A in list.
        \item [Second] item B in list.
        \item [Third] item C in list.
    \end{description}
\end{mdframed}

\noindent\textbf{foreach in description (works):}\par
\begin{description}
    \MyForEachLoop%
\end{description}%

\begin{mdframed}[backgroundcolor=red!25,frametitle={foreach in description in mdframed  (does NOT work):}]
    \begin{description}
        \MyForEachLoop%
    \end{description}%
\end{mdframed}
\end{document}

Answer 1

这是在组中执行其工作时通常会遇到的问题\foreach。我不太明白为什么它在中不起作用mdframed，但我想这是因为trivlist使用了。\item执行时，标签被存储以供稍后排版（这允许\label使用），显然存储箱被覆盖，使其为空。

此代码显示了所涉及的分组，其排版description正确：

\documentclass{article}
\usepackage{xcolor}
\usepackage{mdframed}
\usepackage{pgffor,etoolbox}

\newcommand*{\MyForEachLoop}{%
    \foreach \x/\y in {
            First/{item A in list},
            Second/{item B in list},
            Third/{item C in list}} {%
      \xdef\realitem{\noexpand\item[\expandonce{\x}] \expandonce{\y}.}%
      \aftergroup\realitem
    }%
}

\mdfsetup{frametitlerule=true}

\begin{document}
\begin{mdframed}[backgroundcolor=red!25,frametitle={foreach in description in mdframed}]
\begin{description}
\MyForEachLoop
\end{description}
\end{mdframed}
\end{document}

部分\item[\x]\y.存储在 中\realitem，在组之后执行。