ConfigurationValue.cs

using Microsoft.Extensions.Configuration;
using System;
using System.Collections.Generic;
using System.Text;

namespace JMS.Common
{
    public class ConfigurationValue<T>
    {
        public event EventHandler<ValueChangedArg<T>> ValueChanged;
        /// <summary>
        /// 转换后对象，对象会自动随着配置文件更新而更新
        /// </summary>
        public T Current { get; private set; }
        IDisposable _disposable;
        internal ConfigurationValue(IConfiguration configuration)
        {
            callback(configuration);
        }

        void callback(object state)
        {
            _disposable?.Dispose();
            IConfiguration configuration = (IConfiguration)state;
            var old = this.Current;
            this.Current = configuration.Get<T>();           
            _disposable = configuration.GetReloadToken().RegisterChangeCallback(callback, configuration);
            try
            {
                this.ValueChanged?.Invoke(this, new ValueChangedArg<T>
                {
                    OldValue = old,
                    NewValue = this.Current
                });
            }
            catch
            {
            }
        }
    }

    public class ValueChangedArg<T>
    {
        public T OldValue { get; set; }
        public T NewValue { get; set; }
    }
}