.net - ASP.NET MVC2 站点可以有一个可选的枚举路由参数吗？如果是这样，如果未提供，我们可以默认该值吗？

Question

我可以有一条路线吗...

routes.MapRoute(
    "Boundaries-Show",
    "Boundaries",
     new 
     {
         controller = "Boundaries", 
         action = "Show",
         locationType = UrlParameter.Optional
     });

Action 方法在哪里...

[HttpGet]
public ActionResult Show(int? aaa, int? bbb, LocationType locationType) { ... }

如果此人没有提供 locationType 的值.. 那么它默认为 LocationType.Unknown .

这可能吗？

更新 #1

我已经剥离了 action 方法以包含一个方法(直到我开始工作)。现在看起来像这样..

[HttpGet]
public ActionResult Show(LocationType locationType = LocationType.Unknown) { .. }

.. 我收到此错误消息...

The parameters dictionary contains an invalid entry for parameter 'locationType' for method 'System.Web.Mvc.ActionResult Show(MyProject.Core.LocationType)' in 'MyProject.Controllers.GeoSpatialController'. The dictionary contains a value of type 'System.Int32', but the parameter requires a value of type 'MyProject.Core.LocationType'. Parameter name: parameters

是否认为可选路由参数 LocationType是 int32 而不是自定义 Enum ?

Answer 1

您可以像这样提供默认值:

public ActionResult Show(int? aaa, int? bbb, LocationType locationType = LocationType.Unknown) { ... }

更新:

或者，如果您使用的是 .NET 3.5:

public ActionResult Show(int? aaa, int? bbb, [DefaultValue(LocationType.Unknown)] LocationType locationType) { ... }

更新 2:

public ActionResult Show(int? aaa, int? bbb, int locationType = 0) {
  var _locationType = (LocationType)locationType;
}

public enum LocationType {
    Unknown = 0,
    Something = 1
}