Edit table of contents [book] [duplicate]

Question

I'd like to edit the table of contents for a book-class file. The problem that I'm facing is that I have a lot of separate Chapters, with no sections, in the first part of the book. If I just use \tableofcontents it looks like this:

I Part
1. Chapter
   1.1 Section
II Part
   2. Chapter

etc. which is generally fine, but since I have a lot of chapters it looks somewhat ugly. I'd would like something like this

I Part
   I.1. Chapter
     I.1.1 Section
   I.2. Chapter

II Part
   II.1. Chapter

but I honestly have no idea how to realize that. I'll also add an example code here, since I'm not sure if there could be a problem with the subfile-package

\documentclass[a4paper, leqno, oneside]{book}
\usepackage{subfiles}
\usepackage[utf8]{inputenc}
\usepackage[ngerman]{babel}
\usepackage{amssymb,amsmath, amsthm,mathtools,latexsym}
\usepackage{mathrsfs}
\usepackage{geometry}
\usepackage{soul}

\begin{document}
\subfile{Preface.tex}
\tableofcontents
\subfile{Part1.tex}
\subfile{Part2.tex}
\subfile{Part3.tex}

\end{document}

Thanks for the help!

Answer 1

In order to include the part number into the numbering scheme of chapters, sections,... and change the spacing in the table of contents you can use the tocloft package as shown in the following MWE:

\documentclass[a4paper, leqno, oneside]{book}
\usepackage{geometry}
\usepackage{tocloft}
\renewcommand{\thechapter}{\thepart.\arabic{chapter}}
\setlength{\cftchapindent}{2em}
\setlength{\cftsecindent}{4em}
\setlength{\cftsubsecindent}{6em}
\setlength{\cftchapnumwidth}{2em}
\setlength{\cftsecnumwidth}{3em}
\setlength{\cftsubsecnumwidth}{4em}

\begin{document}
\tableofcontents
\part{one}
\chapter{first chapter}
\section{section}
\subsection{subsection}
\chapter{second chapter}
\end{document}

\cft...indent controls the indentation from the left margin, while \cft...numwidth controls the space that can be occupied by the numbers. You can of course adjust them to suit your needs.