ASP.NET MVC 3 路由约束 : Regular Expression for not null

Question

我正在尝试创建一个路线约束，但不确定什么是最好的。这是没有限制的路线:

context.MapRoute(
    "Accommodation_accomm_tags",
    "accomm/{controller}/{action}/{tag}",
    new { action = "Tags", controller = "AccommProperty" },
    new { tag = @"" } //Here I would like to put a RegEx for not null match
);

最好的解决方案是什么？

Answer 1

您能否创建一个IRouteConstraint:

public class NotNullRouteConstraint : IRouteConstraint
{
  public bool Match(
    HttpContextBase httpContext, Route route, string parameterName, 
    RouteValueDictionary values, RouteDirection routeDirection)
  {
    return (values[parameterName] != null);
  }
}

您可以连接:

context.MapRoute(
  "Accommodation_accomm_tags",
  "accomm/{controller}/{action}/{tag}",
  new { action = "Tags", controller = "AccommProperty" },
  new { tag = new NotNullRouteConstraint() }
);