asp.net mvc filter

Using Filters to Attach Reusable Behaviors

 

Introducing the Four Basic Types of Filters

 

 

Notice that ActionFilterAttribute is the default implementation for both IActionFilter
and IResultFilter—it implements both of those interfaces. It’s meant to be totally general
purpose, so it doesn’t provide any implementation (in fact, it’s marked abstract, so you can
only use it by deriving a subclass from it). However, the other default implementations
(AuthorizeAttribute and HandleErrorAttribute) are concrete, contain useful logic, and can
be used without deriving a subclass.
To get a better understanding of these types and their relationships, examine Figure 9-6.
It shows that all filter attributes are derived from FilterAttribute, and also implement one or
more of the filter interfaces. The dark boxes represent ready-to-use concrete filters; the rest are
interfaces or abstract base classes. Later in this chapter, you’ll learn more about each built-in
filter type.

 

MyFilter Demo:

 

01	using System;

02	using System.Collections.Generic;

03	using System.Linq;

04	using System.Web;

05	using System.Web.Mvc;

06

07	namespace TestMvcWebApp1.ActionResultEx

08

{

09	public class ShowMessageAttribute:ActionFilterAttribute

10

{

11	public string Message { get; set; }

12	public override void OnActionExecuting(ActionExecutingContext filterContext)

13

{

14	filterContext.HttpContext.Response.Write("[BeforeAction " + Message + "]");

15

}

16	public override void OnActionExecuted(ActionExecutedContext filterContext)

17

{

18	filterContext.HttpContext.Response.Write("[AfterAction " + Message + "]");

19

}

20	public override void OnResultExecuting(ResultExecutingContext filterContext)

21

{

22	filterContext.HttpContext.Response.Write("[BeforeResult " + Message + "]");

23

}

24	public override void OnResultExecuted(ResultExecutedContext filterContext)

25

{

26	filterContext.HttpContext.Response.Write("[AfterResult " + Message + "]");

27

}

28

}

29

}

 

 

 

使用：

 

01	using System;

02	using System.Collections.Generic;

03	using System.Linq;

04	using System.Web;

05	using System.Web.Mvc;

06	using TestMvcWebApp1.ActionResultEx;

07	using System.Data.SqlClient;

08

09	namespace TestMvcWebApp1.Controllers

10

{

11	public class ShowMessageDemoController : Controller

12

{

13

//

14	// GET: /ShowMessageDemo/

15	[ShowMessage(Message = "這是我的資訊A" , Order=1)]

16	[HandleError(View="Problem")]

17	public ActionResult Index()

18

{

19	int a = 0;

20	SqlConnection conn = new SqlConnection();

21	conn.Open();

22

23	return Content("  網頁內容  ");

24

}

25

26

}

27

}

 

輸出結果：

[BeforeAction 這是我的資訊A][AfterAction 這是我的資訊A]

[BeforeResult 這是我的資訊A]  網頁內容  [AfterResult 這是我的資訊A]

 

 <customErrors mode="On"></customErrors>

 

Using Filters to Attach Reusable Behaviors

 

Introducing the Four Basic Types of Filters

 

 

Notice that ActionFilterAttribute is the default implementation for both IActionFilter
and IResultFilter—it implements both of those interfaces. It’s meant to be totally general
purpose, so it doesn’t provide any implementation (in fact, it’s marked abstract, so you can
only use it by deriving a subclass from it). However, the other default implementations
(AuthorizeAttribute and HandleErrorAttribute) are concrete, contain useful logic, and can
be used without deriving a subclass.
To get a better understanding of these types and their relationships, examine Figure 9-6.
It shows that all filter attributes are derived from FilterAttribute, and also implement one or
more of the filter interfaces. The dark boxes represent ready-to-use concrete filters; the rest are
interfaces or abstract base classes. Later in this chapter, you’ll learn more about each built-in
filter type.

 

MyFilter Demo:

 

01	using System;

02	using System.Collections.Generic;

03	using System.Linq;

04	using System.Web;

05	using System.Web.Mvc;

06

07	namespace TestMvcWebApp1.ActionResultEx

08

{

09	public class ShowMessageAttribute:ActionFilterAttribute

10

{

11	public string Message { get; set; }

12	public override void OnActionExecuting(ActionExecutingContext filterContext)

13

{

14	filterContext.HttpContext.Response.Write("[BeforeAction " + Message + "]");

15

}

16	public override void OnActionExecuted(ActionExecutedContext filterContext)

17

{

18	filterContext.HttpContext.Response.Write("[AfterAction " + Message + "]");

19

}

20	public override void OnResultExecuting(ResultExecutingContext filterContext)

21

{

22	filterContext.HttpContext.Response.Write("[BeforeResult " + Message + "]");

23

}

24	public override void OnResultExecuted(ResultExecutedContext filterContext)

25

{

26	filterContext.HttpContext.Response.Write("[AfterResult " + Message + "]");

27

}

28

}

29

}

 

 

 

使用：

 

01	using System;

02	using System.Collections.Generic;

03	using System.Linq;

04	using System.Web;

05	using System.Web.Mvc;

06	using TestMvcWebApp1.ActionResultEx;

07	using System.Data.SqlClient;

08

09	namespace TestMvcWebApp1.Controllers

10

{

11	public class ShowMessageDemoController : Controller

12

{

13

//

14	// GET: /ShowMessageDemo/

15	[ShowMessage(Message = "這是我的資訊A" , Order=1)]

16	[HandleError(View="Problem")]

17	public ActionResult Index()

18

{

19	int a = 0;

20	SqlConnection conn = new SqlConnection();

21	conn.Open();

22

23	return Content("  網頁內容  ");

24

}

25

26

}

27

}

 

輸出結果：

[BeforeAction 這是我的資訊A][AfterAction 這是我的資訊A]

[BeforeResult 這是我的資訊A]  網頁內容  [AfterResult 這是我的資訊A]

 

 <customErrors mode="On"></customErrors>