ASP.NET MVC使用Action过滤器处理方法

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Action过滤器在动作方法之前及之后运行，Result过滤器在动作结果被执行之前和之后运行。

1、Action过滤器

在ASP.NET MVC中创建MvcApp项目，创建文件夹Filter，然后新建类MyActionFilterAttribute（为了遵循默认的约定，名称以Attribute结尾），继承自ActionFilterAttribute类。ActionFilterAttribute类有如下4个方法。

using System;
 
namespace System.Web.Mvc
{
    [AttributeUsage(AttributeTargets.Class | AttributeTargets.Method, Inherited = true, AllowMultiple = false)]
    public abstract class ActionFilterAttribute : FilterAttribute, IActionFilter, IResultFilter
    {
 
        protected ActionFilterAttribute();
 
        public virtual void OnActionExecuted(ActionExecutedContext filterContext);
 
        public virtual void OnActionExecuting(ActionExecutingContext filterContext);
 
        public virtual void OnResultExecuted(ResultExecutedContext filterContext);
 
        public virtual void OnResultExecuting(ResultExecutingContext filterContext);
    }
}

实现MyActionFilterAttribute类：

using System;
using System.Web.Mvc;
 
namespace MvcApp.Filter
{
    public class MyActionFilterAttribute : ActionFilterAttribute
    {
        public override void OnActionExecuting(ActionExecutingContext filterContext)
        {
            //1、获取请求的类名和方法名
            string strController = filterContext.RouteData.Values["controller"].ToString();
            string strAction = filterContext.RouteData.Values["action"].ToString();
 
            //2、用另一种方式获取请求的类名和方法名
            string strController2 = filterContext.ActionDescriptor.ControllerDescriptor.ControllerName;
            string strAction2 = filterContext.ActionDescriptor.ActionName;
 
            filterContext.HttpContext.Response.Write("控制器：" + strController + "<br/>");
            filterContext.HttpContext.Response.Write("控制器：" + strController2 + "<br/>");
            filterContext.HttpContext.Response.Write("Action：" + strAction + "<br/>");
            filterContext.HttpContext.Response.Write("Action：" + strAction2 + "<br/>");
 
            filterContext.HttpContext.Response.Write("Action执行前：" + DateTime.Now.ToString("yyyy-MM-dd hh:mm:ss fff") + "<br/>");
            base.OnActionExecuting(filterContext);
        }
 
        public override void OnActionExecuted(ActionExecutedContext filterContext)
        {
            filterContext.HttpContext.Response.Write("Action执行后：" + DateTime.Now.ToString("yyyy-MM-dd hh:mm:ss fff") + "<br/>");
            base.OnActionExecuted(filterContext);
        }
    }
}

对于过滤器，我们可以把它们加在3个地方，一个是控制器上面（控制器下面的所有Action），一个是Action上面（指定标识的Action），另一个就是全局位置（所有控制器中的Action）。这里只演示在Action上面和Home控制器中：

[MyActionFilter]
public ActionResult Index()
{
    return View();
}

2、Result过滤器

新建MyResultFilterAttribute类，继承ActionFilterAttribute：

using System;
using System.Web.Mvc;
 
namespace MvcApp.Filter
{
    public class MyResultFilterAttribute : ActionFilterAttribute
    {
        /// <summary>
        /// 加载“视图”前执行
        /// </summary>
        /// <param name="filterContext"></param>
        public override void OnResultExecuting(ResultExecutingContext filterContext)
        {
            filterContext.HttpContext.Response.Write("加载视图前执行 OnResultExecuting" + DateTime.Now.ToString("yyyy-MM-dd hh:mm:ss fff") + "<br/>");
            base.OnResultExecuting(filterContext);
        }
 
        /// <summary>
        /// 加载“视图”后执行
        /// </summary>
        /// <param name="filterContext"></param>
        public override void OnResultExecuted(ResultExecutedContext filterContext)
        {
            filterContext.HttpContext.Response.Write("加载视图后执行 OnResultExecuted" + DateTime.Now.ToString("yyyy-MM-dd hh:mm:ss fff") + "<br/>");
            base.OnResultExecuted(filterContext);
        }
    }
}

这里把MyResultFilter过滤器加在控制器上面，相当于给Home控制器中的所有的Action方法添加了MyResultFilter过滤器。

using MvcApp.Filter;
using System.Web.Mvc;
 
namespace MvcApp.Controllers
{
    [MyResultFilter]
    public class HomeController : Controller
    {
        [MyActionFilter]
        public ActionResult Index()
        {
            return View();
        }
    }
}

运行结果，如下图：

示例：使用Action过滤器，实现操作日志的记录功能。

在Models目录下创建OperateLogModel.cs（操作日志实体类）：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;

namespace MvcApp.Models
{
    /// <summary>
    /// 操作日志实体类
    /// </summary>
    public class OperateLogModel
    {
        /// <summary>
        /// 控制器名称
        /// </summary>
        public string ControllerName { get; set; }

        /// <summary>
        /// Action名称
        /// </summary>
        public string ActionName { get; set; }

        /// <summary>
        /// 功能模块
        /// </summary>
        public string FunctionalModule { get; set; }

        /// <summary>
        /// 操作类型
        /// </summary>
        public string OperationType { get; set; }

        /// <summary>
        /// 操作时间
        /// </summary>
        public DateTime OperationDate { get; set; }

        /// <summary>
        /// 路径
        /// </summary>
        public string Path { get; set; }

        /// <summary>
        /// 请求参数
        /// </summary>
        public string Params { get; set; }
    }
}

创建Filter目录，并在该目录下创建OperateLogAttribute类，继承ActionFilterAttribute类：

using MvcApp.Models;
using Newtonsoft.Json;
using System;
using System.IO;
using System.Text;
using System.Web;
using System.Web.Mvc;

namespace MvcApp.Filter
{
    /// <summary>
    /// 操作日志
    /// </summary>
    public class OperateLogAttribute : ActionFilterAttribute
    {
        /// <summary>
        /// 功能模块
        /// </summary>
        public string FunctionalModule { get; set; }

        /// <summary>
        /// 操作类型
        /// </summary>
        public string OperationType { get; set; }

        /// <summary>
        /// 记录请求日志
        /// </summary>
        public override void OnActionExecuting(ActionExecutingContext filterContext)
        {
            //创建操作日志实体类
            OperateLogModel requestLog = new OperateLogModel();
            requestLog.ControllerName = filterContext.ActionDescriptor.ControllerDescriptor.ControllerName;
            requestLog.ActionName = filterContext.ActionDescriptor.ActionName;
            requestLog.FunctionalModule = this.FunctionalModule;
            requestLog.OperationType = this.OperationType;
            requestLog.OperationDate = DateTime.Now;
            requestLog.Path = filterContext.RequestContext.HttpContext.Request.Path;
            requestLog.Params = GetStrPatams(filterContext.RequestContext.HttpContext.Request);

            //记录日志
            string logJson = JsonConvert.SerializeObject(requestLog);
            WriteLog(logJson);
        }

        /// <summary>
        /// 获取字符串参数
        /// </summary>
        public string GetStrPatams(HttpRequestBase theRequest)
        {
            string result = "";
            string url = theRequest.Url.ToString();

            string method = theRequest.HttpMethod;
            if (method == "GET")
            {
                result = theRequest.QueryString.ToString();
            }
            else if (method == "POST")
            {
                result = theRequest.Form.ToString();
            }

            //if (result == "")
            //{
            //    result = theRequest.Params.ToString();
            //}

            if (result.Length > 0)
            {
                result = HttpUtility.UrlDecode(result, Encoding.UTF8);
            }

            return result;
        }

        /// <summary>
        /// 写入日志
        /// </summary>
        public void WriteLog(string message)
        {
            string path = AppDomain.CurrentDomain.BaseDirectory + "/MyLog.txt";
            using (StreamWriter sw = new StreamWriter(path, true, Encoding.Default))
            {
                sw.Flush();
                sw.WriteLine("时间：" + DateTime.Now);
                sw.WriteLine("内容：" + message);
                sw.WriteLine("-------------------------");
            }
        }
    }
}

创建OrderController.cs（订单控制器），编写新增订单方法，并在该方法上添加OperateLog特性：

using MvcApp.Filter;
using MvcApp.Models;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.Mvc;

namespace MvcApp.Controllers
{
    /// <summary>
    /// 订单控制器
    /// </summary>
    public class OrderController : Controller
    {
        /// <summary>
        /// 新增订单
        /// </summary>
        [OperateLog(FunctionalModule = "订单业务", OperationType = "新增")]
        public bool AddOrder(string orderName, decimal price)
        {
            return true;
        }
    }
}