Why does cached data disappear when using forceLoad in a Blazor app?

Hi @Obakeng Aphane ,

When you call NavigateTo(..., forceLoad: true), you trigger a full browser page load. That tears down the current Blazor runtime, so anything held only in memory—like your IMemoryCache in a WASM (or client-hydrated InteractiveAuto) session—is lost.

Summary:

• forceLoad: false: SPA navigation, runtime stays alive, in‑memory cache survives.
• forceLoad: true: full reload, new runtime, in‑memory cache emptied.

If you need certain values to survive a hard reload, mirror them into browser storage and rehydrate them on startup.

LocalStorage vs SessionStorage

• localStorage: persists across tabs and browser restarts (until cleared).
• sessionStorage: lasts only for the current tab (ends when tab closes).
• Both store simple string key/value pairs (you JSON‑serialize objects).
• Not secure for sensitive data (visible to the user; no encryption by default).
• Size limits are small (a few MB), so store only what you must.

Minimal pattern:

1. Before navigation: serialize the values you care about.
2. On app start (e.g., in OnInitializedAsync of a root/service): read, deserialize, and repopulate your in‑memory cache.

// Save
await js.InvokeVoidAsync("localStorage.setItem", "myCache", JsonSerializer.Serialize(cacheObject));
 
// Load
var json = await js.InvokeAsync<string>("localStorage.getItem", "myCache");
if (!string.IsNullOrEmpty(json))
{
    var restored = JsonSerializer.Deserialize<MyCacheDto>(json);
    // repopulate your cache
}

Doc starting points:

• General Blazor state guidance: State management in Blazor
• Protected (server-side) browser storage: [Protected browser storage](https://free.blessedness.top/en-us/aspnet/core/blazor/state-management/protected-browser-storage?vie…
• Prerender/state transfer (if needed): Prerender and integrate server and client state Keep the in‑memory cache for fast lookups during a single runtime, and only persist the minimal subset you need to survive reloads.

Hope this helps. Let me know if you need any help.

Auto render means you running the blazor app as a WASM with server pre-render. When you set forceReload to true, the browser unloads and reloads the app. As the memory cache is in the browser WASM, it is lost on the reload.