IOptionsMonitor.cs

// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.

using System;
using System.Diagnostics.CodeAnalysis;

namespace Microsoft.Extensions.Options
{
    /// <summary>
    /// Used for notifications when <typeparamref name="TOptions"/> instances change.
    /// </summary>
    /// <typeparam name="TOptions">The options type.</typeparam>
    public interface IOptionsMonitor<[DynamicallyAccessedMembers(Options.DynamicallyAccessedMembers)] out TOptions>
    {
        /// <summary>
        /// Returns the current <typeparamref name="TOptions"/> instance with the <see cref="Options.DefaultName"/>.
        /// </summary>
        TOptions CurrentValue { get; }

        /// <summary>
        /// Returns a configured <typeparamref name="TOptions"/> instance with the given name.
        /// </summary>
        TOptions Get(string? name);

        /// <summary>
        /// Registers a listener to be called whenever a named <typeparamref name="TOptions"/> changes.
        /// </summary>
        /// <param name="listener">The action to be invoked when <typeparamref name="TOptions"/> has changed.</param>
        /// <returns>An <see cref="IDisposable"/> which should be disposed to stop listening for changes.</returns>
        IDisposable OnChange(Action<TOptions, string?> listener);
    }
}