How do I initialize variables at startup in a Blazor webassembly app? - initialization

Question

In UWP, I would programmatically initialize display variables at startup so that the initial display was what I wanted, for example, values based on the day of the year value. I can't crack where to replicate this in my otherwise working Blazor webassembly app. I currently put up default values and ask the user to click a button, that calculates and updates to the values I want to display and on we go.
I would have thought there's a standard, easy way to do this, but given how Blazor pieces are constructed on the fly in order to render as web pages, maybe not? Thanks!

Answer 1

This isn't specific to Blazor, but in any class you can create code in the constructor of your component/
Here I have a Chat component, that I break up into
Chat.razor
Chat.razor.cs
The chat.razor.cs you create by adding a class with the same name as your component, then add the word partial to make it a partial class:
partial class Chat : IBlazorComponent, IBlazorComponentParent, IDisposable
Note: The interfaces are just for my app, I am just showing the line with partial.
really are you need it:
partial class Chat
Then in my constructor I created:
public Chat()
{
// Perform initializations for this object
Init();
}
I just call a method, you don't have to:
My Init method:
public void Init()
{
// do your initializations
}
Or you can use OnInitializedAsync
protected override async Task OnInitializedAsync()
{
// load the Categories (example)
this.Categories = await HelpCategoryService.GetHelpCategoryList()
}
Or here is another I use sometimes: OnAfterRender
protected override void OnAfterRender(bool firstRender)
{
if (firstRender)
{
...
}
}
Documentation for that is here:
https://learn.microsoft.com/en-us/aspnet/core/blazor/lifecycle?view=aspnetcore-3.1
Maybe that gives you some ideas. Not sure about Standard, every use case is different.
Note: I have never used Blazor Web Assembly, only server side Blazor, so not sure what is specific to WASM, but I know constructors work in any C# class.

Answer 2

I assume you want to have global Variables for your app:
Create a Initialize service that initializes your static data.
public class InitializeService
{
public InitializeService()
{
MyStaticDataClass.Variable1 == "Pling";
MyStaticDataClass.Variable1 == "GlobalPlong";
}
}
In startup services.AddSingleton().
Your MyStaticDataClass vars will now be available from your app and pages