This is the archived version of Roland Weigelt's weblog that ran from 2003 to 2023 at weblogs.asp.net

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Archives / 2018 / November

  • How to Make Chrome Kiosk Mode “just Work”

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    There’s a reason why I haven’t blogged about UWP lately: The overall development experience (slow turnaround cycles, silent crashes, HRESULTs instead of error messages, you name it) drove me mad up to the point I scrapped my whole project, a digital signage solution, in early summer. Instead, I now use Chrome as my “render engine” and things are working pretty well. Without prior experience in using ASP.Net Core, WebAPI and SignalR, I have been able to whip something up to be ready for the 2018/19 Basketball season.

    During development, I had to figure out

    1. how to use Chrome without any… chrome (i.e. no title, adress or tool bars),
    2. how to move the Chrome window to the secondary screen,
    3. how to close Chrome from code and
    4. how to still be able to use Chrome for browsing during development.

    tl;dr: On https://github.com/RWeigelt/ChromeKioskModeDemo you find a small demo project (C#/WinForms for simplicity) that’s pretty self-explanatory.

    Problems #1 and #2 are easy: Chrome has a so-called kiosk mode (command line parameter --kiosk http://www.example.com) that will display the specified web page in full-screen mode. Another command line parameter deals with with positioning (--window-position=top,left). In the demo code you’ll see other parameters, they force the window size for a cleaner startup.

    Problems #3 and #4 turned out to be connected to each other.

    One might wonder what’s so hard about closing Chrome from code. Don’t you just start a process with Process.Start and remember the returned Process instance, to later call its CloseMainWindow method? What could possibly go wrong?

    Well, for starters, that Process instance may live shorter than expected. If you have a couple of Chrome windows and/or tabs open, Chrome will do a lot of process management behind the scenes – and “your” process may not be the one displaying the requested web page.

    On the other hand, if you go from zero Chrome windows to one window with a single tab, things are nice and easy. Now while you could force yourself to use a different browser during development, you never now whether there isn’t some Chrome window open later in production.

    Fortunately, if you specify a different “user data directory” (--user-data-dir=directory) when starting Chrome, you can achieve this “one window, one tab, one process” scenario even if you have many windows and tabs open.

    For details, take a look at the code on https://github.com/RWeigelt/ChromeKioskModeDemo. This C#/WinForms project shows a form with two buttons:

    • “Open Chrome” will open http://www.example.com in full-screen mode on the second monitor (sorry, you have to have a second monitor for the demo).
    • “Close Chrome” closes the Chrome window without affecting any other Chrome windows.

    Note that this is not a library, just some code I have taken from my solution (stripped down for clarity). You’ll want to adapt it to your needs anyway. Have fun with it!