How to set minimum height for multipart rectangles with multiple lines of text in it?

Question

I've tried to apply the answer in Minimum height in split rectangle (with many thanks to Alain Matthes) using their defined mystrut.

I modified their code to have two lines in each nodepart

in the section of their code after % Split Rectangle, when I add \centerline{......} \centerline{........} after \nodepart{one} \mystrut, it will only modify the height of the box around the first line instead of the entire \nodepart{one}, how can I fix it?.

The modified code:

\documentclass{standalone}

\usepackage{tikz}
\usetikzlibrary{shapes,arrows,positioning}
\def\mystrut{\vrule height 1.5cm depth 1.5cm width 0pt} 

\begin{document}    

\begin{tikzpicture}[auto,
rect/.style={
    rectangle split,
    rectangle split parts=4,
    draw=black,
    rounded corners,
    text width = 3cm
}]  


% Split Rectangle
\node [rect] {
  \mystrut  \centerline{First} \\ \centerline{Item}
    \nodepart{two}\mystrut \centerline{Second} \\ \centerline{Item}
    \nodepart{three} \centerline{$\vdots$}
    \nodepart{four} \mystrut \centerline{Last} \\ \centerline{Item}
    };

\end{tikzpicture}
\end{document}    

Result:

Answer 1

You need to put a \mystrut on each line you want the space added to, including the second line of each part, if applicable.

Better than using \centerline, which should be used very rarely in LaTeX, use the align or rectangle split parts align styles.

Do you want something like this?

If so, I think it is more straightforward to play with inner xsep and inner ysep.

\documentclass[border=10pt]{standalone}
\usepackage{tikz}
\usetikzlibrary{shapes.multipart}
\begin{document}
\begin{tikzpicture}[auto,
  rect/.style={
    rectangle split,
    rectangle split parts=4,
    draw=black,
    rounded corners,
    rectangle split part align=center,
    align=center,
    inner ysep=12mm,
    inner xsep=10mm,
  }]
  % Split Rectangle
  \node [rect] {%
    First\\Item
    \nodepart{two}Second\\Item
    \nodepart{three}$\vdots$
    \nodepart{four}Last\\Item%
  };
\end{tikzpicture}
\end{document}

EDIT

If you want something more like the following:

then you might want to use \mystrut, but redefine it to take arguments. In the following, the first argument is the height and the second the depth. For two-line nodes, we set the second argument to zero on the first line and the first argument to zero on the second.

\documentclass[border=10pt]{standalone}
\usepackage{tikz}
\usetikzlibrary{shapes.multipart}
\newcommand*\mystrut[2]{\vrule height #1 depth #2 width 0pt}
\begin{document}
\begin{tikzpicture}[auto,
  rect/.style={
    rectangle split,
    rectangle split parts=4,
    draw=black,
    rounded corners,
    rectangle split part align=center,
    align=center,
%     inner ysep=12mm,
    inner xsep=10mm,
  }]
  % Split Rectangle
  \node [rect] {%
    \mystrut{15mm}{0pt}First\\\mystrut{0pt}{15mm}Item
    \nodepart{two}\mystrut{10mm}{0pt}Second\\\mystrut{0pt}{10mm}Item
    \nodepart{three}\mystrut{5mm}{5mm}$\vdots$
    \nodepart{four}\mystrut{25mm}{0pt}Last\\\mystrut{0pt}{25mm}Item%
  };
\end{tikzpicture}
\end{document}