An example of how to handle null when using OnInitializedAsync to fetch data to display in a Blazor component

OnInitializedAsyncExample.razor

<h2>@Config?.WelcomeMessage</h2>

@code {
    protected ConfigObject? Config { get; set; }

    protected int RenderCount { get; set; }

    protected override async Task OnInitializedAsync()
    {
        Console.WriteLine(RenderCount); // 0
        // await "triggers" the next steps in the component lifecycle, such as rendering
        Config = await ReturnHelloWorldAsync();
        Console.WriteLine(RenderCount); // 1
    }

    protected override void OnAfterRender(bool firstRender)
    {
        RenderCount++;
    }

    protected async Task<ConfigObject> ReturnHelloWorldAsync()
    {
        await Task.Delay(100); // Simulating some asynchronous operation
        return new ConfigObject();
    }

    protected class ConfigObject
    {
        public string WelcomeMessage => "Hello World!";
    }
}

OnInitializedExample.razor

<h2>@Config.WelcomeMessage</h2>

@code {
    protected ConfigObject Config { get; set; } = null!;

    protected int RenderCount { get; set; }
    
    // completes before rendering part of lifecycle and can be used like a constructor for setting properties
    protected override void OnInitialized()
    {
        Console.WriteLine(RenderCount); // 0
        Config = new();
        Console.WriteLine(RenderCount); // 0
    }

    protected override void OnAfterRender(bool firstRender)
    {
        RenderCount++;
    }

    protected class ConfigObject
    {
        public string WelcomeMessage => "Hello World!";
    }
}