为什么 \clearfield 没有抑制 Biblatex 脚注中的问题编号？

Question

该\clearfield命令应该在 中全局抑制问题编号biblatex，但在下面的 MWE 中，它只抑制了参考书目中的问题编号，并且它在脚注中幽灵般地重新出现。这是为什么？我怎样才能在所有地方抑制问题编号？

\documentclass{article}
\usepackage[british]{babel}
\usepackage[autostyle]{csquotes}
\usepackage[style=oscola,backend=biber,ibidtracker=true,ibidstyle=lc,giveninits,ecli=true]{biblatex}
\AtEveryBibitem{%
\ifentrytype{article}{
    \clearfield{issue}%
    \clearfield{number}%
}{}}
\addbibresource{mylibrary.bib}
\begin{filecontents}{mylibrary.bib}
@article{VanderMeulen2013,
author = {van der Meulen, Bernd},
doi = {10.3390/laws2020069},
issn = {2075-471X},
journal = {Laws},
number = {2},
pages = {69--98},
title = {{The Structure of European Food Law}},
volume = {2},
year = {2013}
}

\end{filecontents}
\begin{document}
    A sentence.\autocites{VanderMeulen2013}
    
    \printbibliography
\end{document}

Answer 1

\AtEveryBibitem仅适用于参考书目。如果您需要将\clearfields 也应用于引文，则可以使用\AtEveryCitekey。但这当然会使您必须编写的代码行数增加一倍。

\documentclass{article}
\usepackage[british]{babel}
\usepackage[autostyle]{csquotes}
\usepackage[backend=biber,
  style=oscola,
  giveninits,
  ibidtracker=true, ibidstyle=lc,
  ecli=true,
]{biblatex}

\AtEveryBibitem{%
  \ifentrytype{article}
    {\clearfield{issue}%
     \clearfield{number}}
    {}}
\AtEveryCitekey{%
  \ifentrytype{article}
    {\clearfield{issue}%
     \clearfield{number}}
    {}}

\begin{filecontents}{\jobname.bib}
@article{VanderMeulen2013,
  author  = {van der Meulen, Bernd},
  doi     = {10.3390/laws2020069},
  issn    = {2075-471X},
  journal = {Laws},
  number  = {2},
  pages   = {69--98},
  title   = {The Structure of {European} Food Law},
  volume  = {2},
  year    = {2013},
}
\end{filecontents}
\addbibresource{\jobname.bib}

\begin{document}
  A sentence.\autocites{VanderMeulen2013}
    
  \printbibliography
\end{document}

---

为了从输出中完全删除字段，我通常更喜欢使用源映射解决方案，该解决方案在从.bib文件中读取字段时删除这些字段。

\documentclass{article}
\usepackage[british]{babel}
\usepackage[autostyle]{csquotes}
\usepackage[backend=biber,
  style=oscola,
  giveninits,
  ibidtracker=true, ibidstyle=lc,
  ecli=true,
]{biblatex}

\DeclareSourcemap{
  \maps[datatype=bibtex]{
    \map{
      \pertype{article}
      \step[fieldset=number, null]
      \step[fieldset=issue, null]
    }
  }
}

\begin{filecontents}{\jobname.bib}
@article{VanderMeulen2013,
  author  = {van der Meulen, Bernd},
  doi     = {10.3390/laws2020069},
  issn    = {2075-471X},
  journal = {Laws},
  number  = {2},
  pages   = {69--98},
  title   = {The Structure of {European} Food Law},
  volume  = {2},
  year    = {2013},
}
\end{filecontents}
\addbibresource{\jobname.bib}

\begin{document}
  A sentence.\autocites{VanderMeulen2013}
    
  \printbibliography
\end{document}