How to set in-text citations in italic?

Question

I'm using the authoryear-comp citestyle of biblatex and I'd like the author and year to appear in italics in in-text citations. After some research, I've found the following command, but it only italicizes the author:

\renewcommand{\mkbibnamelast}[1]{\mkbibemph{#1}}

Does anyone know, on the basis of the following example, how to get the year italicized as well?

\documentclass{scrbook}

\usepackage[backend=biber, bibstyle=authoryear, citestyle=authoryear-comp,sorting=nyt]{biblatex}
\addbibresource{\jobname.bib}
\usepackage{filecontents}

\begin{filecontents*}{\jobname.bib}
    @book{Knu86,
        author = {Knuth, Donald E.},
        year = {1986},
        title = {The \TeX book},
    }
\end{filecontents*}

Many thanks for having a look at this and best wishes,

Answer 1

One way to make citation italic is to inject a \mkbibemph into the wrapper code of \DeclareCiteCommand for the relevant \...cite commands you want to be in italic.

You can find the \DeclareCiteCommand declarations in <citestyle>.cbx (in your case authoryear-comp.cbx). Note that these definitions can differ between styles, so you need to make sure you have got the correct ones.

In the example we show how to make \cite/\cite* and \parencite/\parencite* italic. The original definitions can be found in authoryear-comp.cbx, ll. 160-190 in v3.16: For \cite we just add \mkbibemph as wrapper command (because \cite does not have a wrapper). For \parencite we combine \mkbibemph with the wrapper \mkbibparens (change the order of \mkbibemph and \mkbibparens in \mkbibemphparens to make the parentheses italic too).

\documentclass[british]{article}
\usepackage[T1]{fontenc}
\usepackage{babel}
\usepackage{csquotes}

\usepackage[backend=biber, style=authoryear-comp]{biblatex}

\DeclareCiteCommand{\cite}[\mkbibemph]
  {\usebibmacro{cite:init}%
   \usebibmacro{prenote}}
  {\usebibmacro{citeindex}%
   \usebibmacro{cite}}
  {}
  {\usebibmacro{postnote}}

\DeclareCiteCommand*{\cite}[\mkbibemph]
  {\usebibmacro{cite:init}%
   \usebibmacro{prenote}}
  {\usebibmacro{citeindex}%
   \usebibmacro{citeyear}}
  {}
  {\usebibmacro{postnote}}

\newcommand*{\mkbibemphparens}[1]{\mkbibparens{\mkbibemph{#1}}}

\DeclareCiteCommand{\parencite}[\mkbibemphparens]
  {\usebibmacro{cite:init}%
   \usebibmacro{prenote}}
  {\usebibmacro{citeindex}%
   \usebibmacro{cite}}
  {}
  {\usebibmacro{postnote}}

\DeclareCiteCommand*{\parencite}[\mkbibemphparens]
  {\usebibmacro{cite:init}%
   \usebibmacro{prenote}}
  {\usebibmacro{citeindex}%
   \usebibmacro{citeyear}}
  {}
  {\usebibmacro{postnote}}

\addbibresource{biblatex-examples.bib}

\begin{document}
Lorem \autocite{sigfridsson}
ipsum \parencite{nussbaum}
dolor \cite{worman}

\printbibliography
\end{document}