现在的企业级开发项目，特别是网站一般都会用到log功能，想想大部分会用Enterprise Logging Application Block 的功能 或者自己写一个组件，记录系统日志事件，更好的跟踪了解系统运行情况, 现用ASP.NET MVC 的过滤属性实现log功能！
ASP.NET MVC的filter 是一个属性，可以应用到controller 后者action.当Controller或者action method 被调用时，ASP.NET MVC的filter在调用执行前后会被触发。 先看下当Control 里面的action 被调用时的利用继承,自定义类log的效果图：
要实现上面的效果，现自定义一个类LogMessageAttribute,LogMessageAttribute继承接口IActionFilter ,IResultFilter,也可以选择性的继承重写类FilterAttribute。
IActionFilter interface 定义为：
publicinterface IActionFilter
{
// Methods
void OnActionExecuted(ActionExecutedContext filterContext);
void OnActionExecuting(ActionExecutingContext filterContext);
}
OnActionExecuting ：在Controller 里面的action method 调用之前运行
OnActionExecuted：在Controller 里面的action method 调用之后运行，但是在IResultFilter接口的OnResultExecuting方法执行之前
IResultFilter interface定义为：
publicinterface IResultFilter
{
// Methods
void OnResultExecuted(ResultExecutedContext filterContext);
void OnResultExecuting(ResultExecutingContext filterContext);
}
OnResultExecuting：在Controller 里面的action method调用处理玩前执行.
OnResultExecuted：在Controller 里面的action method调用处理玩后执行.
接下来是重头戏：LogMessageAttribute自定义类
[AttributeUsage(AttributeTargets.Class |AttributeTargets.Method ,Inherited=true ,AllowMultiple=true )]
publicclass LogMessageAttribute:FilterAttribute,IActionFilter,IResultFilter
{
/// <summary>
/// <param name="LogName ">日志文件路径</para>
/// </summary>
publicstring LogName { get; set; }
/// <summary>
/// 记录时间，系统版本，当前线程ID 等记录
/// </summary>
/// <param name="controller"></param>
/// <param name="action"></param>
/// <param name="message"></param>
publicvoid LogMessage(string controller, string action, string message)
{
if (!string.IsNullOrEmpty(LogName))
{
TextWriter writer = new StreamWriter(LogName, true);
writer.WriteLine("################# Begin #################");
writer.WriteLine("Time:[{0}]",DateTime.Now.ToString("yyyy-MM-dd- hh:mm:ss"));
writer.WriteLine("Controller:{0}",controller);
writer.WriteLine("Action:{0}",action);
writer.WriteLine("Message:{0}",message);
writer.WriteLine("Operating System version is:{0}",System.Environment.OSVersion.Version.ToString());
writer.WriteLine("Current Thread ID is:{0}",AppDomain.GetCurrentThreadId());
writer.WriteLine("############### Over ###############");
writer.Close();
}
}
publicvoid OnActionExecuting(ActionExecutingContext filterContext)
{
LogMessage(filterContext.RouteData.Values["controller"].ToString(),
filterContext.RouteData.Values["action"].ToString(),
"Action exeuting...");
}
publicvoid OnActionExecuted(ActionExecutedContext filterContext)
{
LogMessage(filterContext.RouteData.Values["controller"].ToString(),
filterContext.RouteData.Values["action"].ToString(),
"Action executed.");
}
publicvoid OnResultExecuting(ResultExecutingContext filterContext)
{
LogMessage(filterContext.RouteData.Values["controller"].ToString(),
filterContext.RouteData.Values["action"].ToString(),
"Result executing...");
}
publicvoid OnResultExecuted(ResultExecutedContext filterContext)
{
LogMessage(filterContext.RouteData.Values["controller"].ToString(),
filterContext.RouteData.Values["action"].ToString(),
"Result executed");
}
}
自定义好LogMessageAttribute类，应用到Controller或者action的属性。在Controller 正在执行，或者呈现一个View,一个HTTP请求数据时，就会在日志文件记录一些日志.
在项目的Controller里面应用自定义的属性
[Logging(LogName = @"D:\Project\Project\MVCProject\sky.ExtendMVCFramework\sky.ExtendMVCFramework\Log.log")]
public ActionResult DesplayEmployee()
{
ViewData["Message"] = "Our employees welcome you to our site!";
List<Employee> employees = new List<Employee>
{
new Employee {
FirstName="sky",
LastName="yang",
Email = "weflytotti@163.com",
Department ="Development"
},
new Employee {
FirstName="sky",
LastName="yang",
Email = "weflytotti@163.com",
Department ="Development"
}
};
return View(employees);
}
运行程序，正如文章开始所看到的截图！
总结：自定义ASP.NET MVC 的过滤属性实现自己想要的功能只需要继承IActionFilter ,IResultFilter。
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