\documentclass[a4paper]{article}
\usepackage{lmodern}
\usepackage{amssymb,amsmath}
\usepackage[T1]{fontenc}
\usepackage[utf8]{inputenc}
\usepackage{hyperref}
\usepackage{tikz}
\begin{document}
\tikzstyle{every node}=[draw=black,thick,anchor=west]
\tikzstyle{selected}=[draw=red,fill=red!30]
\tikzstyle{dir}=[fill=gray!50]
\tikzstyle{relativeTo}=[fill=blue!70]
\begin{tikzpicture}[%
grow via
three points={one child at (0.5,-0.7) and
two children at
(0.5,-0.7) and (0.5,-1.4)},
edge from
parent path={(\tikzparentnode.south)
 |- (\tikzchildnode.west)}]
\node {/ oder C:}
\child { \node {home}
  \child { \node {knut}
    \child { \node {pictures} }
    \child { \node {docs}
      \child { \node [dir] {latex}
        \child { \node [relativeTo] {main.tex} }
        \child { \node [selected] {part1.tex} }
      }
    }
  }
};
\end{tikzpicture}
\end{document}