Initial commit: Lagerbestand Blazor Projekt

Lagerbestand/Components/Shared/VisibilityRefresh.cs

@@ -0,0 +1,43 @@
+using Microsoft.JSInterop;
+
+namespace Lagerbestand.Components.Shared;
+
+/// <summary>
+/// Helper that wires a page's reload method to the browser's
+/// <c>visibilitychange</c> event via <c>appInterop.registerVisibilityRefresh</c>.
+/// The caller owns the <see cref="DotNetObjectReference"/> passed in.
+/// </summary>
+public static class VisibilityRefresh
+{
+    /// <summary>
+    /// Registers a .NET callback invoked when the browser tab becomes
+    /// visible again after being hidden for at least <paramref name="thresholdSeconds"/>.
+    /// </summary>
+    public static async Task RegisterAsync<T>(
+        IJSRuntime js,
+        DotNetObjectReference<T> dotNetRef,
+        string methodName,
+        int thresholdSeconds = 120) where T : class
+    {
+        try
+        {
+            await js.InvokeVoidAsync("appInterop.registerVisibilityRefresh", dotNetRef, methodName, thresholdSeconds);
+        }
+        catch
+        {
+            // Circuit may be mid-reconnect — non-fatal.
+        }
+    }
+
+    /// <summary>
+    /// Unregisters the visibility callback. Safe to call multiple times.
+    /// </summary>
+    public static async Task UnregisterAsync(IJSRuntime js)
+    {
+        try
+        {
+            await js.InvokeVoidAsync("appInterop.unregisterVisibilityRefresh");
+        }
+        catch { /* ignore */ }
+    }
+}