/// <summary>
/// Subscribes to the data produced by the <see cref="IDataLoader"/> in order to update its state without reloading the <see cref="IDataLoader"/>.
/// </summary>
/// <remarks>
/// This makes sense when <typeparamref name="TData"/> is something observable such as <see cref="INotifyCollectionChanged"/>.
/// </remarks>
/// <typeparam name="TData">The type of data.</typeparam>
/// <param name="builder">The builder.</param>
/// <param name="subscribeToData">
/// The method subscribing to the data.
/// Use that method to subscribe to events available on <typeparamref name="TData"/> and return an IDisposable that unsubscribes from events.
/// Your event handlers should leverage <see cref="IDataLoaderSetter.SetData(object)"/> and <see cref="IDataLoaderSetter.SetError(Exception)"/>.
/// </param>
/// <returns>The original <paramref name="builder"/>.</returns>
public static IDataLoaderBuilder <TData> SubscribeToData <TData>(
this IDataLoaderBuilder <TData> builder,
Func <TData, IDataLoaderSetter, IDisposable> subscribeToData)
{
var namePrefix = builder.Name == null ? string.Empty : builder.Name + ".";
var trigger = new SubscribeToDataTrigger(namePrefix + nameof(SubscribeToDataTrigger));
var strategy = new SubscribeToDataStrategy(data => subscribeToData((TData)data, trigger));
return(builder
.WithTrigger(trigger)
.WithStrategy(strategy));
}
/// <summary>
/// Tries to subscribe to the data produced by the <see cref="IDataLoader"/> in order to update its state without reloading the <see cref="IDataLoader"/>.
/// </summary>
/// <remarks>
/// This makes sense when <typeparamref name="TData"/> is something observable such as <see cref="INotifyCollectionChanged"/>.
/// You should use this method with <see cref="DataLoaderBuilderFactory.DataLoaderBuilderFactory(Func{IDataLoaderBuilder, IDataLoaderBuilder})"/> so that all DataLoaders of <typeparamref name="TData"/> subscribe to their data automatically.
/// </remarks>
/// <typeparam name="TData">The type of data.</typeparam>
/// <param name="builder">The builder.</param>
/// <param name="subscribeToData">
/// The method subscribing to the data.
/// Use that method to subscribe to events available on <typeparamref name="TData"/> and return an IDisposable that unsubscribes from events.
/// Your event handlers should leverage <see cref="IDataLoaderSetter.SetData(object)"/> and <see cref="IDataLoaderSetter.SetError(Exception)"/>.
/// </param>
/// <returns>The original <paramref name="builder"/>.</returns>
public static IDataLoaderBuilder TrySubscribeToData <TData>(
this IDataLoaderBuilder builder,
Func <TData, IDataLoaderSetter, IDisposable> subscribeToData)
{
// Early-out 1: The SubscribeToData delegating strategy is already present in the builder.
if (builder.DelegatingStrategies.Any(s => s is SubscribeToDataStrategy))
{
return(builder);
}
// Early-out 2: The builder isn't typed.
if (builder.DataType == null)
{
if (typeof(SubscribeToDataExtensions).Log().IsEnabled(LogLevel.Error))
{
typeof(SubscribeToDataExtensions).Log().LogError("Can't validate type. Make sure the 'IDataLoaderBuilder.DataType' property is set before calling 'TrySubscribeToData'.");
}
return(builder);
}
var dataType = typeof(TData);
// Early-out 3: The builder type doesn't match TData.
if (!dataType.IsAssignableFrom(builder.DataType))
{
// If TData doesn't match the builder type, we don't do anything.
return(builder);
}
var namePrefix = builder.Name == null ? string.Empty : builder.Name + ".";
var trigger = new SubscribeToDataTrigger(namePrefix + nameof(SubscribeToDataTrigger));
var strategy = new SubscribeToDataStrategy(data => subscribeToData((TData)data, trigger));
return(builder
.WithTrigger(trigger)
.WithStrategy(strategy));
}
