using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.Mvc;
using System.Data.SqlClient;
using System.IO;

namespace _3_異常過濾器.Controllers
{
    public class ErrorController : Controller
    {
        // GET: Error
        [HandleError(ExceptionType =typeof(ArithmeticException),View ="Error")]
        public ActionResult Index(int a,int b)
        {
            int c = a / b;
            ViewData["Result"] = c;
            return View();
        }

        /// <summary>
        /// 測試數據庫異常
        /// </summary>
        /// <returns></returns>
        [HandleError(ExceptionType = typeof(SqlException), View = "Error")]
        public ActionResult DbError()
        {
            // 錯誤的連接字符串
            SqlConnection conn = new SqlConnection(@"Initial Catalog=StudentSystem; Integrated Security=False;User Id=sa;Password=******;Data Source=127.0.0.1");
            conn.Open();
            // 返回Index視圖
            return View("Index");
        }

        /// <summary>
        /// IO異常
        /// </summary>
        /// <returns></returns>
        [HandleError(ExceptionType = typeof(IOException), View = "Error")]
        public ActionResult IOError()
        {
            // 訪問一個不存在的文件
            System.IO.File.Open(@"D:\error.txt",System.IO.FileMode.Open);
            // 返回Index視圖
            return View("Index");
        }
    }
}

2、路由配置如下：

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

namespace _3_異常過濾器
{
    public class RouteConfig
    {
        public static void RegisterRoutes(RouteCollection routes)
        {
            routes.IgnoreRoute("{resource}.axd/{*pathInfo}");

            routes.MapRoute(
                name: "Default",
                url: "{controller}/{action}/{id}",
                defaults: new { controller = "Home", action = "Index", id = UrlParameter.Optional }
            );

            // 新增路由配置
            routes.MapRoute(
              name: "Default2",
              url: "{controller}/{action}/{a}/",
              defaults: new { controller = "Home", action = "Index", a=0,b=0 }
          );
        }
    }
}

3、配置文件如下：

<system.web>
    <compilation debug="true" targetFramework="4.6.1" />
    <httpRuntime targetFramework="4.6.1" />
    <httpModules>
      <add name="ApplicationInsightsWebTracking" type="Microsoft.ApplicationInsights.Web.ApplicationInsightsHttpModule, Microsoft.AI.Web" />
    </httpModules>
    <!--customErrors配置節(jié)mode的屬性值必須為On-->
    <customErrors mode="On">    
    </customErrors>
</system.web>

4、運行結果

URL：http://localhost:21868/error/index/8/4

結果：

URL：http://localhost:21868/error/index/8/0

結果：

URL：http://localhost:21868/error/DbError

結果：

URL：http://localhost:21868/error/IOError

結果：

在同一個控制器或Action方法上可以通過HandleError處理多個異常，通過Order屬性決定捕獲的先后順序,但最上面的異常必須是下面異常的同類級別或子類。如下圖所示：

上面的程序可以修改成如下的代碼：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.Mvc;
using System.Data.SqlClient;
using System.IO;

namespace _3_異常過濾器.Controllers
{
    [HandleError(Order =1, ExceptionType = typeof(SqlException), View = "Error")]
    [HandleError(Order =2, ExceptionType = typeof(IOException), View = "Error")]
    [HandleError(Order =3)] //不指定View，默認跳轉到Share下面的Error視圖
    public class ErrorController : Controller
    {
        public ActionResult Index(int a,int b)
        {
            int c = a / b;
            ViewData["Result"] = c;
            return View();
        }

        /// <summary>
        /// 測試數據庫異常
        /// </summary>
        /// <returns></returns>
        public ActionResult DbError()
        {
            // 錯誤的連接字符串
            SqlConnection conn = new SqlConnection(@"Initial Catalog=StudentSystem; Integrated Security=False;User Id=sa;Password=******;Data Source=127.0.0.1");
            conn.Open();
            // 返回Index視圖
            return View("Index");
        }

        /// <summary>
        /// IO異常
        /// </summary>
        /// <returns></returns>
        public ActionResult IOError()
        {
            // 訪問一個不存在的文件
            System.IO.File.Open(@"D:\error.txt",System.IO.FileMode.Open);
            // 返回Index視圖
            return View("Index");
        }
    }
}

在上面的示例中，捕獲異常的時候只是跳轉到了Error視圖，如果我們想獲取異常的具體信息該怎么辦呢？如下圖所示：