moderncv: How to extract the style information and use it in if-statements

Question

I use moderncv for my CV and changed the header for the classic and the casual style (but not the other three styles), following the advice from this post:

Moderncv adding date of birth to personal information

That worked as a charm regarding the layout. I put each changed \makecvhead{} macro in a separate file, put them in the main LaTeX-document with \input and if I want the classic or the casual style, I have to remove the comment accordingly:

%\input{dateofbirth_for_casual}
\input{dateofbirth_for_classic}

To learn something new, and for the sake of simplicity, now I want to just change the style in \moderncvstyle{} and the rest should be taken care of automatically, i.e. the appropriate header should be used as necessary.

It boils down to the question:

How can I extract which style is defined by the user (aka myself) programmatically and use it in if-statements?

Something like this:

\ifthenelse{\equal{\@moderncvstyle}{classic}}{
    %do something because it's classic
}{}
\ifthenelse{\equal{\@moderncvstyle}{casual}}{
    %do something because it's casual
}{}

From scanning the code of "moderncv.cls" and the other files in the package, I have no clue where the value of \moderncvstyle{} is stored, and I do not know if my test is okay or maybe I have to put the testing condition in quotation marks or anything..?

\ifthenelse{\equal{**WHAT IS THE STYLE?**}{"casual"}}{
    %do something because it's casual
}{}

At the end I only want to have one file as \input I use everytime and don't want to care anymore which changed header is used:

\input{dateofbirth_for_classic_or_casual}

Thanks!

---

Not working ME with pseudo code:

\documentclass[12pt]{moderncv}
\moderncvstyle{casual}

% Pseudo-Code starts here:

% If style = casual
% do this
% if style = classic
% do that
% if style = banking or fancy or oldstyle
% do nothing    

\name{John}{Doe}
\address{111 Mimimi}{Here}{Somewhere}
\phone[mobile] {+01~(0)123 456789}
\email{John.Doe@mail.com} 
\begin{document}
\makecvtitle
\end{document}

Answer 1

The style loaded with \moderncvstyle is not stored to some macro, but this can be changed by patching \moderncvstyle.

The definition in moderncv.cls is

\newcommand*{\moderncvstyle}[2][]{
  \RequirePackage[#1]{moderncvstyle#2}}

so basically it is sufficient to catch the 2nd argument and redefine a storage macro, say \@moderncvstyle which can be evaluated later on.

I used the traditional \ifnum0=\pdfstrcmp{}{} test here, since \pdfstrcmp is a pdftex primitive.

\documentclass[12pt]{moderncv}

\usepackage{xpatch}

\makeatletter
\providecommand{\@moderncvstyle}{}
\providecommand{\@moderncvstyleoptions}{}
\xapptocmd{\moderncvstyle}{%
  \renewcommand{\@moderncvstyleoptions}{#1}{}{}
  \renewcommand{\@moderncvstyle}{#2}{}{}
}
\makeatother

\moderncvstyle{banking}


\makeatletter

\ifnum0=\pdfstrcmp{\@moderncvstyle}{casual}
\typeout{Yes, it's casual type}
\else
\ifnum0=\pdfstrcmp{\@moderncvstyle}{classic}
\typeout{Yes, it's classic type}
\else
\ifnum0=\pdfstrcmp{\@moderncvstyle}{banking}
\typeout{Yes, it's banking type}
\fi
\fi
\fi
\makeatother

% Pseudo-Code starts here:

% If style = casual
% do this
% if style = classic
% do that
% if style = banking or fancy or oldstyle
% do nothing    

\name{John}{Doe}
\address{111 Mimimi}{Here}{Somewhere}
\phone[mobile] {+01~(0)123 456789}
\email{John.Doe@mail.com} 
\begin{document}
\makecvtitle
\end{document}

Answer 2

In case someone is needing the functionality of adding a birth of date and the family status, too, I posted an example with the appropriate headers for all five styles here:

https://tex.stackexchange.com/a/376850/136789

The variant with \ifnum0=\pdfstrcmp strangely did not work for me so I did it using \ifthenelse but nevertheless @christian-hupfer provided the framework to get it working in the first place.