songhejia / filter Goto Github PK

可分别定义方法执行前过滤器, 方法执行结束过滤器, 方法异常过滤器

• 执行前过滤器继承 ExecutingFilterAttribute 抽象类, 实现 Execute 抽象方法, 参数 parameters 为运行时拦截方法的参数列表

    /// <summary>
    /// 自定义执行前过滤器
    /// </summary>
    public class CustomExecutingFilterAttribute : ExecutingFilterAttribute
    {
        public string Name { get; set; }
  
        public override void Execute(MethodParameters[] parameters)
        {
            Console.WriteLine("=====================================================================");
            if (parameters != null)
                Console.WriteLine($"执行前过滤器：{nameof(CustomExecutingFilterAttribute)}, Data:{this.Name}, Param:{string.Join(", ", parameters?.Select(p => p.ToString()))}");
            else
                Console.WriteLine($"执行前过滤器：{nameof(CustomExecutingFilterAttribute)}, Data:{this.Name}");
        }
    }
  

• 执行后过滤器继承 ExecutedFilterAttribute 抽象类, 实现 Execute 抽象方法,其中泛型参数 returned 为拦截方法返回值, 对于无返回值的方法(void),此参数默认为数字 0

    /// <summary>
    /// 自定义执行后过滤器
    /// </summary>
    public class CustomExecutedFilterAttribute : ExecutedFilterAttribute
    {
        public override void Execute<TReturn>(MethodParameters[] parameters, TReturn returned)
        {
            if (parameters != null)
                Console.WriteLine($"执行后过滤器：{nameof(CustomExecutedFilterAttribute)},Param:{string.Join(", ", parameters?.Select(p => p.ToString()))}, Return:{returned}");
            else
                Console.WriteLine($"执行后过滤器：{nameof(CustomExecutedFilterAttribute)},Return:{returned}");
            Console.WriteLine("=====================================================================\r\n");
        }
    }
  

• 异常过滤器继承 ErrorFilterAttribute 抽象类, 实现 Execute 抽象方法, 其中参数 ex 为拦截方法抛出的未处理异常

    /// <summary>
    /// 自定义错误过滤器
    /// </summary>
    public class CustomErrorFilterAttribute : ErrorFilterAttribute
    {
        public override void Execute(MethodParameters[] parameters, Exception ex)
        {
            Console.ForegroundColor = ConsoleColor.Red;
            if (parameters != null)
                Console.WriteLine($"异常过滤器：{nameof(CustomErrorFilterAttribute)}, Param:{string.Join(", ", parameters?.Select(p => p.ToString()))},Exception:{ex}");
            else
                Console.WriteLine($"异常过滤器：{nameof(CustomErrorFilterAttribute)}, Exception:{ex}");
            Console.ResetColor();
        }
    }
  

    public interface IRepository
    {
        void Add<T>(T entity);

        void Remove<T>(T entity);

        void Update<T>(T entity, Func<T, bool> predicate);
    }

public class Repository : IRepository
{
    private List<string> list = new List<string>();

    //运用过滤器
    [CustomExecutingFilter]
    [CustomExecutedFilter]
    [CustomErrorFilter]
    public void Add<T>(T entity)
    {
        list.Add(entity.ToString());
        Console.WriteLine($"Added: Count-{list.Count}");
    }

    //运用过滤器
    [CustomExecutingFilter]
    [CustomExecutedFilter]
    [CustomErrorFilter]
    public void Remove<T>(T entity)
    {
        list.Remove(entity.ToString());
        Console.WriteLine($"Removed: Count-{list.Count}");
    }

    //运用过滤器
    [CustomExecutingFilter]
    [CustomExecutedFilter]
    [CustomErrorFilter]
    public void Update<T>(T entity, Func<T, bool> predicate)
    {
        var item = list.FirstOrDefault(p => predicate(entity));
        if (item == null)
            throw new Exception("列表中不存在更新的项");
        list.Remove(item);
        list.Add(entity.ToString());
    }
}

    //实例化接口实现类
    var repo = new Repository();
    //动态生成代理
    var repoProxy = EmitGenerator<IRepository>.GenerateProxy(repo);

    //使用代理调用方法
    repoProxy.Add("Hello");
    repoProxy.Add("World");
    repoProxy.Remove("World");
    repoProxy.Update("A,ning", p => p == "World");   //将会抛出列表中不存在项异常