Blazor - Customize the startup message


We all have seen the little “Loading…” message that appears with you are starting up a Blazor client-side application.  A quick text search you can see the text in the index.html page under the wwwroot folder.  It is simple enough to change the text to anything you would like.

But what if you wanted to have a cool animated gif or a awesome CSS spinner?  When I first thought about doing this, I googled for it.  I did not find too many examples to work with.  I did find that Telerik has a component for this, but you must buy their tool set.  I took a step back and thought about it.  We are talking about just an HTML page. 


Standard Loading:




First Try

My first step was to create a class with a CSS spinner in it and add that class to:

<app class=”myspinner”>
</app>

Surprisingly, the spinner showed during loading nicely.  Unfortunately, once the first page of the application loaded, the spinner was still going.  I figured no problem.  I fixed this with the page spinner I previously built.  I just need to hide it once the page is loaded.  And I can do that in the page OnInitializedAsync() method.

But there is a problem, this is not with in a not a blazor component, it is a DOM element.  Well, I could use JSInterOp, but I rather not.  The <app> is a component, but it the bootstrapper for our Blazor app and the spinner is setting outside of it.


Second Try

With my first try a semi-failure, I decided to just put the spinner inside the <app> component, since that is where the “Loading…” text is and it disappears once the app is loaded.  So, I added a div with my loader class attached to it.  I added a little extra test as well. 

<div class="loader">I am running a pretty
spinner!!</div>

 This worked!!  The spinner loaded and ran with the text displayed, then once the first page of the application loaded, the text and spinner where gone because the DOM was updated.


Third Try

At this point I am feeling pretty confident so I decided to try an animated gif.  That worked as well,

<app>
    <img src="img/giphy.gif"  alt="Smiley face"
height="450" width="450" class="center"/>
</app>

 


Turns out this is very straight forward, and you can add any HTML/CSS you would like to control how your application looks on start up.   You are only limited my your imagination.


I have include the image and the CSS for the spinner I used in the source code in GitHub.

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