Component Services

Arbiter.Components registers a small set of services through AddArbiterComponents. This page covers the notification service, the principal component base and data service, and the base address resolver.

Notification service

INotificationService displays short-lived, non-blocking notification messages. Messages are queued immediately and shown as toasts through IToaster; warnings and errors are also logged. Inject INotificationService into a component and call the appropriate method.

Method	Description
`ShowInformation(message)`	Displays an informational message
`ShowSuccess(message)`	Displays a success message
`ShowWarning(message)`	Displays a warning message
`ShowWarning(exception, message)`	Logs the exception and displays a warning
`ShowError(message)`	Displays an error message
`ShowError(exception, message)`	Logs the exception and displays an error
`Clear()`	Dismisses all displayed notifications

A common pattern surfaces exceptions from a try/catch block. This example is adapted from samples/EntityFramework/src/Tracker.Client/Components/EntitySelect.razor:

[Inject]
public required INotificationService Notification { get; set; }

protected async Task<IReadOnlyList<TModel>> LoadData()
{
    try
    {
        var query = new EntityQuery { Filter = Filter };
        query.AddSort(Sort ?? TModel.SortField());

        var result = await DataService.Page<TModel>(query, CacheTime);
        return result?.Data ?? [];
    }
    catch (Exception ex)
    {
        Notification.ShowError(ex);
        return [];
    }
    finally
    {
        await InvokeAsync(StateHasChanged);
    }
}

ShowError also accepts a plain string for validation-style messages:

if (SecurityKeyId == 0)
{
    Notification.ShowError("Please select a security key.");
    return;
}

Notification options

NotificationServiceOptions configures how notifications are displayed. Set them through the AddArbiterComponents overload — see Components Overview.

Option	Default	Description
`ShowExceptionDetails`	`false`	When `true`, includes full exception messages in error toasts. Intended for development only
`ErrorMessage`	—	The default message shown for errors when details are hidden
`WarningMessage`	—	The default message shown for warnings
`WarningTimeout`	`15` seconds	How long a warning notification is displayed
`ErrorTimeout`	`30` seconds	How long an error notification is displayed

Principal component base

PrincipalComponentBase is the base component for pages that need the current user, claims, roles, or authorization policies. It reads from the cascading AuthenticationState, so the authentication and authorization services must be registered — see Components Overview.

The concrete page components (ViewPageBase, EditPageBase, and the list bases) already derive from PrincipalComponentBase, so their pages have access to the current user without additional setup. Inherit from it directly for custom pages that are not one of the standard patterns:

@page "/logging"

@inherits PrincipalComponentBase

@code {
    [Inject]
    public required INotificationService Notification { get; set; }

    [Inject]
    public required IDispatcher Dispatcher { get; set; }

    protected virtual async ValueTask<DataResult<LogRecord>> LoadData(DataRequest request)
    {
        try
        {
            var command = new LogRecordQuery
            {
                PageSize = request.PageSize,
                ContinuationToken = request.ContinuationToken
            };

            var results = await Dispatcher.Send(command);
            return new DataResult<LogRecord>(results?.Data ?? []);
        }
        catch (Exception ex)
        {
            Notification.ShowError(ex);
            return new DataResult<LogRecord>([]);
        }
    }
}

Custom base components can also extend PrincipalComponentBase to share behavior across a set of pages while retaining access to the current principal.

Principal data service

PrincipalDataService extends DispatcherDataService and resolves the current user from the Blazor authentication state, preferring the cascaded authentication state task and falling back to the authentication state provider. AddArbiterComponents registers it as the IDispatcherDataService implementation, so commands and queries sent through the data service carry the current principal. No page-level code is required to use it.

Base address resolver

BaseAddressResolver implements IBaseAddressResolver and resolves the Blazor application base address, preferring the NavigationManager base URI and falling back to configuration. The configuration key is BaseAddress. AddArbiterComponents registers it automatically; it is used internally when a component or service needs the application base address.

Next steps

Component Extensions — navigation, data grid, and string helpers
Components Overview — registration and configuration