A look at persistence of rendered content with the different variants of Blazor Apps.

The previous post contrasted Blazor Server and Web Assembly apps. This post is a short tutorial that exemplifies the differences with respect to the persistence of rendered content as available to a browser when the host web service is running or not. As part of this, the persistence of Progresive Web Apps (PWA) is demonstarted.


  • Create a Blazor Server app in Visual Studio
  • Run the server app
    • Observe the Index page
    • Copy the Url
    • Stop debugging
      • Note that the browser closes
    • Open a new broswer and paste the URL
      • Note no response

So the Blazor Server app needs the service to be running.

  • Create a Blazor Wasm app (No PWA ASP.NET Core) in Visual Studio
  • Run the wasm app
    • Observe the Index page
    • Stop debugging
      • Note that the browser does not close
    • Note that you CAN navigate between the pages
      • Try a refresh, all OK
    • Make a change to the Index page, say, “Hello World Again”.
    • Restart debugging and note the change in tab new tab
    • Go back the first tab and note that when you navigate away from the Index page and return it is still unchanged.
    • Do a refresh now and note that you now get the update in the first tab.
    • Copy the URL and stop debugging
    • Open a new browser and and paste the URL.
      • Note that the app is rendered and you can navigate between pages!
      • Close all broswers and repeat this and note it still works.
      • Clear all browser hsistory and cached data, repeat and note the app still runs !!
      • Where is the app cached??

So the Blazor Web Assembly App caches the app (somewhere) and is available even when the service stops.

Continuing with the Wasm app:

  • Make a copy of the URL, to say, Notepad and save it.
    • Reboot the system and try it now. Note that the app didn’t survive the reboot
  • Create a new Wasm app but this time enable PWA.
  • Run the app (Debug) then note the circled plus as below:
    • Note that on a phone you get a request to install it.
  • Click on it and install the app.
  • Close everything and note that you can run it from the Start Menu (on left)
  • Open the project in Visual Studio, make a chenge debug the app then shut everything down.
    • Run the app from the Start Menu again and note tha the changes have made it through.
  • Rerun the app again from the Start Menu after disabling the network.
    • Note that the app works OK regardless
  • Reboot and see that you it won’t run.
    • Its looking for the IIS Express to check for updates, I guess, but can’t find it.
    • For this to work you need to deploy the Wasm to a server that is not transitory??

So each your heart out Click-Once! Move over for Progressive Web Apps.

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