In dired-mode, I want to have a split view of the directory listing on the left window and to quickly browse the content of each file on the right window. The default file visit command keeps opening a new window for each file which needs closing. It's really annoying. I put the following in init.el file and bind it to a key. It loads the current file under the cursor in the next existing window on right, on left, above, below, or opening a new window as needed.

  ;; In dired mode, visit the file at the cursor in the right/below/left/above window.
  (defun my-dired-display-direction ()
    (interactive)
    (let* ((file-or-dir (dired-get-file-for-visit))   ;; get the file at cursor
           (buffer (find-file-noselect file-or-dir))) ;; load the file into a buffer
      (let ((window                                   ;; figure out the window to use
             (cond ((get-buffer-window buffer (selected-frame)))
                   ((window-in-direction 'right))     ;; try window in each direction
                   ((window-in-direction 'below))     ;; and default to right
                   ((window-in-direction 'left))      ;; if no window found.
                   ((window-in-direction 'above))
                   (t (split-window (selected-window) nil 'right)))))
        (window--display-buffer buffer window 'window nil)
        window)) )
  
  ;; Bind ctrl-o to display at direction.
  (define-key dired-mode-map (kbd "C-o") 'my-dired-display-direction)