tracks form changes and warns users before navigation

2025-12-25 23:55:04 -05:00
parent 059a16b958
commit 77b5683804
8 changed files with 156 additions and 8 deletions
@@ -0,0 +1,93 @@
+@namespace WebApp.Components.Shared.Components
+@implements IDisposable
+@inject IDialogService DialogService
+@inject NavigationManager NavigationManager
+
+@code {
+    [CascadingParameter]
+    private EditContext? EditContext { get; set; }
+
+    [Parameter]
+    public EditContext? ExplicitEditContext { get; set; }
+
+    [Parameter]
+    public bool Enabled { get; set; } = true;
+
+    private bool _isDirty = false;
+    private bool _allowNavigation = false;
+    private IDisposable? _navigationRegistration;
+
+    protected override void OnInitialized()
+    {
+        var contextToUse = ExplicitEditContext ?? EditContext;
+
+        if (contextToUse == null)
+        {
+            throw new InvalidOperationException("FormChangeTracker requires an EditContext. Either provide it as a cascading parameter or through the ExplicitEditContext parameter.");
+        }
+
+        // Subscribe to field changes to detect when form becomes dirty
+        contextToUse.OnFieldChanged += HandleFieldChanged;
+
+        // Register navigation handler to intercept navigation attempts
+        _navigationRegistration = NavigationManager.RegisterLocationChangingHandler(OnLocationChanging);
+    }
+
+    private void HandleFieldChanged(object? sender, FieldChangedEventArgs e)
+    {
+        if (Enabled)
+        {
+            _isDirty = true;
+        }
+    }
+
+    private async ValueTask OnLocationChanging(LocationChangingContext context)
+    {
+        // Allow navigation if form isn't dirty, navigation is explicitly allowed, or tracking is disabled
+        if (!_isDirty || _allowNavigation || !Enabled)
+        {
+            return;
+        }
+
+        // Show confirmation dialog
+        var result = await DialogService.ShowMessageBox(
+            "Unsaved Changes",
+            "You have unsaved changes. Are you sure you want to leave this page?",
+            yesText: "Leave",
+            cancelText: "Stay");
+
+        // If user chooses to stay (result is null or false), prevent navigation
+        if (result != true)
+        {
+            context.PreventNavigation();
+        }
+    }
+
+    /// <summary>
+    /// Call this method before programmatic navigation to bypass the unsaved changes warning.
+    /// Use this when the form has been successfully saved or when the user explicitly cancels.
+    /// </summary>
+    public void AllowNavigation()
+    {
+        _allowNavigation = true;
+    }
+
+    /// <summary>
+    /// Reset the dirty state of the form. This marks the form as clean and resets the navigation flag.
+    /// </summary>
+    public void MarkClean()
+    {
+        _isDirty = false;
+        _allowNavigation = false;
+    }
+
+    public void Dispose()
+    {
+        var contextToUse = ExplicitEditContext ?? EditContext;
+        if (contextToUse != null)
+        {
+            contextToUse.OnFieldChanged -= HandleFieldChanged;
+        }
+        _navigationRegistration?.Dispose();
+    }
+}
@@ -1,5 +1,4 @@
@namespace WebApp.Components.Shared.Components
-@using MudBlazor

 <PageTitle>@GetPageTitle()</PageTitle>