C# 自定义对象作为MapRoutes定义的控制器方法中的参数
考虑以下地图路线:C# 自定义对象作为MapRoutes定义的控制器方法中的参数,c#,asp.net-mvc,maproute,C#,Asp.net Mvc,Maproute,考虑以下地图路线: MapRoute( "ResultFormat", "{controller}/{action}/{id}.{resultFormat}", new { controller = "Home", action = "Index", id = 0, resultFormat = "json" } ); MapRoute( "ResultFormat", "{controller}/{action}/{id}.{resultFormat}
MapRoute(
"ResultFormat",
"{controller}/{action}/{id}.{resultFormat}",
new { controller = "Home", action = "Index", id = 0, resultFormat = "json" }
);
MapRoute(
"ResultFormat",
"{controller}/{action}/{id}.{resultFormat}",
new {
controller = "Home",
action = "Index",
id = 0,
resultFormat = Models.ResultFormat.HTML
}
);
它的控制器方法是:
public ActionResult Index(Int32 id, String resultFormat)
{
var dc = new Models.DataContext();
var messages = from m in dc.Messages where m.MessageId == id select m;
if (resultFormat == "json")
{
return Json(messages, JsonRequestBehavior.AllowGet); // case 2
}
else
{
return View(messages); // case 1
}
}
以下是URL场景
将转到案例1Home/Index/1
将转到案例1Home/Index/1.html
将转到案例2Home/Index/1.json
resultFormat
参数的枚举?
解释基本思想的一些伪代码:
namespace Models
{
public enum ResponseType
{
HTML = 0,
JSON = 1,
Text = 2
}
}
地图路线:
MapRoute(
"ResultFormat",
"{controller}/{action}/{id}.{resultFormat}",
new { controller = "Home", action = "Index", id = 0, resultFormat = "json" }
);
MapRoute(
"ResultFormat",
"{controller}/{action}/{id}.{resultFormat}",
new {
controller = "Home",
action = "Index",
id = 0,
resultFormat = Models.ResultFormat.HTML
}
);
控制器方法签名:
public ActionResult Index(Int32 id, Models.ResultFormat resultFormat)
IMHO响应格式是一个贯穿各领域的问题,而不是由控制器来处理。我建议你为这份工作写一封信:
[AttributeUsage(AttributeTargets.Method | AttributeTargets.Class, Inherited = true, AllowMultiple = true)]
public sealed class RespondToAttribute : ActionFilterAttribute
{
public override void OnActionExecuted(ActionExecutedContext filterContext)
{
var resultFormat = filterContext.RouteData.Values["resultFormat"] as string ?? "html";
ViewResult viewResult = filterContext.Result as ViewResult;
if (viewResult == null)
{
// The controller action did not return a view, probably it redirected
return;
}
var model = viewResult.ViewData.Model;
if (string.Equals("json", resultFormat, StringComparison.OrdinalIgnoreCase))
{
filterContext.Result = new JsonResult { Data = model };
}
// TODO: you could add some other response types you would like to handle
}
}
这样可以稍微简化控制器的操作:
[RespondTo]
public ActionResult Index(int id)
{
var messages = new string[0];
if (id > 0)
{
// TODO: Fetch messages from somewhere
messages = new[] { "message1", "message2" };
}
return View(messages);
}
ActionFilter是一个可重用的组件,您可以将其应用于其他操作。您的伪代码将正常工作。默认ModelBinder会自动将url中的字符串转换为Models.ResultFormat enum。
但是,制作ActionFilter会更好,正如Darin Dimitrov所说。这是我提出的ActionFilter:
public sealed class AlternateOutputAttribute :
ActionFilterAttribute, IActionFilter
{
void IActionFilter.OnActionExecuted(ActionExecutedContext aec)
{
ViewResult vr = aec.Result as ViewResult;
if (vr == null) return;
var aof = aec.RouteData.Values["alternateOutputFormat"] as String;
if (aof == "json") aec.Result = new JsonResult
{
JsonRequestBehavior = JsonRequestBehavior.AllowGet,
Data = vr.ViewData.Model,
ContentType = "application/json",
ContentEncoding = Encoding.UTF8
};
}
}
我无法让您的示例代码正常工作。我在这里发布了一个新问题:如果你能看看你有什么特别的问题,那会很棒吗?正如您在另一个问题中建议的那样,您需要重写OnActionExecuted而不是OnResultExecuting方法,因为后者在控制器操作之前运行,并且模型将始终为
null
。