Fix Unhandled DBErrors in ComponentsWebAssembly and Spa templates (#25466)

* Add workaround for EF issue dotnet/efcore#22341

Author: John Luo

src/Middleware/Diagnostics.EntityFrameworkCore/src/DatabaseDeveloperPageExceptionFilter.cs

@@ -38,7 +38,8 @@ public async Task HandleExceptionAsync(ErrorContext errorContext, Func<ErrorCont
             {
                 // Look for DbContext classes registered in the service provider
                 var registeredContexts = errorContext.HttpContext.RequestServices.GetServices<DbContextOptions>()
-                    .Select(o => o.ContextType);
+                    .Select(o => o.ContextType)
+                    .Distinct(); // Workaround for https://github.com/dotnet/efcore/issues/22341
 
                 if (registeredContexts.Any())
                 {

src/ProjectTemplates/Web.ProjectTemplates/content/ComponentsWebAssembly-CSharp/Server/Startup.cs

@@ -49,9 +49,9 @@ public void ConfigureServices(IServiceCollection services)
 #else
                 options.UseSqlite(
                     Configuration.GetConnectionString("DefaultConnection")));
+#endif
 
             services.AddDatabaseDeveloperPageExceptionFilter();
-#endif
 
             services.AddDefaultIdentity<ApplicationUser>(options => options.SignIn.RequireConfirmedAccount = true)
                 .AddEntityFrameworkStores<ApplicationDbContext>();

src/ProjectTemplates/Web.Spa.ProjectTemplates/content/Angular-CSharp/Startup.cs

@@ -42,9 +42,9 @@ public void ConfigureServices(IServiceCollection services)
 #else
                 options.UseSqlite(
                     Configuration.GetConnectionString("DefaultConnection")));
+#endif
 
             services.AddDatabaseDeveloperPageExceptionFilter();
-#endif
 
             services.AddDefaultIdentity<ApplicationUser>(options => options.SignIn.RequireConfirmedAccount = true)
                 .AddEntityFrameworkStores<ApplicationDbContext>();

src/ProjectTemplates/Web.Spa.ProjectTemplates/content/React-CSharp/Startup.cs

@@ -42,9 +42,9 @@ public void ConfigureServices(IServiceCollection services)
 #else
                 options.UseSqlite(
                     Configuration.GetConnectionString("DefaultConnection")));
+#endif
 
             services.AddDatabaseDeveloperPageExceptionFilter();
-#endif
 
             services.AddDefaultIdentity<ApplicationUser>(options => options.SignIn.RequireConfirmedAccount = true)
                 .AddEntityFrameworkStores<ApplicationDbContext>();