I made a `box' float environment, and now I would like to put the caption inside the box

Question

I made a box float using the following:

\usepackage{float}
\newfloat{Box}{t}{bx}[chapter]

and

\begin{Box}[htp]
  \label{box:test}
  \fcolorbox{black}{boxgray}{\parbox[c]{\textwidth}{The text goes here}}
\end{Box}

I would like to have the label, i.e. 'Box 1' appear inside the box in the first row of text. Does anyone have an idea of how to implement this?

A basic version of the file I am using:

\documentclass[11pt]{article}

\usepackage{color}


\definecolor{boxgray}{RGB}{215,215,215}
\usepackage{hyperref}

\usepackage{float}
\newfloat{Box}{t}{bx}[section]


\begin{document}


\section{example}

Something about \ref{box:test}.

\begin{Box}[htp]
  \label{box:test}
  \fcolorbox{black}{boxgray}{\parbox[c]{\textwidth}{The text goes here}}
\end{Box}


\end{document}  

Answer 1

You need an anchor for the label. This is normally done by caption and not by the float environment. This is the reason why you should put the label after caption. In your case there is no anchor. A trick would be:

\usepackage{etoolbox}
\AtBeginEnvironment{Box}{\refstepcounter{Box}}

However there is no hint inside your environment that the reference number contains to the environment. So I suggest the following:

1. Define the new float environment with newfloat
2. Related to point 1 you can setup the caption with captionsetup. (I know caption supports float)
3. Using tcolorbox to draw the frame around the caption.

Here an MWE:

\documentclass[11pt]{article}

\usepackage{xcolor}
\definecolor{boxgray}{RGB}{215,215,215}

\usepackage{caption}
\usepackage{newfloat}%loaded by caption too
\DeclareFloatingEnvironment[%
fileext=bx,%
within=section,%
placement=t,
name=Box,%
listname={List of Boxes},%
]{Boxed}
\captionsetup[Boxed]{justification=justified,format=plain,singlelinecheck=false,skip=0pt}
\usepackage{tcolorbox}
\newcommand*\boxedcaption[2][box:\arabic{Boxed}]%
{\begin{tcolorbox}\caption{#2}\label{#1}\end{tcolorbox}}

\usepackage{lipsum}

\usepackage{hyperref}


\begin{document}


\section{example}

Something about \ref{box:test}.

\begin{Boxed}[htp]
\lipsum[1]
\boxedcaption[box:test]{Text goes here}
\end{Boxed}

Something about \ref{box:2}.

\begin{Boxed}[htp]
\lipsum[2]
\boxedcaption{Text goes here}
\end{Boxed}

\end{document}