tracks form changes and warns users before navigation

WebApp/Components/Features/Teams/Create.razor

@@ -18,6 +18,7 @@
     BackButtonUrl="/teams" />
 
 <EditForm method="post" Model="Team" OnValidSubmit="AddTeam" FormName="create" Enhance>
+    <FormChangeTracker @ref="_formChangeTracker" />
     <AntiforgeryToken />
     <DataAnnotationsValidator />
     <MudGrid>
@@ -67,13 +68,14 @@
 
 <FormActions>
     <MudButton OnClick="AddTeam" Variant="Variant.Filled" Color="Color.Primary">Add</MudButton>
-    <MudButton Href="/teams" Variant="Variant.Text">Cancel</MudButton>
+    <MudButton OnClick="HandleCancel" Variant="Variant.Text">Cancel</MudButton>
 </FormActions>
 
 @code {
     [SupplyParameterFromForm]
     private Team Team { get; set; } = new();
 
+    private FormChangeTracker? _formChangeTracker;
     private List<EventDefinition>? _events;
     private List<Student> _students = [];
     private IEnumerable<Student> _selectedStudents = [];
@@ -159,6 +161,13 @@
         Context.Teams.Add(Team);
 
         await Context.SaveChangesAsync();
+        _formChangeTracker?.AllowNavigation();
+        NavigationManager.NavigateTo("/teams");
+    }
+
+    private void HandleCancel()
+    {
+        _formChangeTracker?.AllowNavigation();
         NavigationManager.NavigateTo("/teams");
     }
 }