使用 mvc 路由约束，因此 url 只能映射到三个可能的参数之一

Posted 2023-02-24

【中文标题】使用 mvc 路由约束，因此 url 只能映射到三个可能的参数之一

【英文标题】：using mvc route constraints so a url can only be mapped to one of three possible params

【发布时间】：2012-03-17 05:38:18

【问题描述】：

这是我的路线：

routes.MapRoute(null, "myaccount/monitor/category", // Matches
                new  controller = "MyAccount", action = "Monitor", category = (string)null 
);

我想添加一个约束，以便类别只能匹配空值或三个参数之一（即概述、投影、历史记录）

【问题讨论】：

我个人更喜欢使用三个独立的路由而不是使用路由约束。

【参考方案1】：

Gaby 发布的内联 Regex 可以正常工作。另一种方法是定义一个自定义 IRouteConstraint：

public class FromValuesListConstraint : IRouteConstraint

    private List<string> _values;

    public FromValuesListConstraint(params string[] values)
    
        this._values = values.Select(x => x.ToLower()).ToList();
    

    public bool Match(HttpContextBase httpContext, Route route, string parameterName, RouteValueDictionary values, RouteDirection routeDirection)
    
        string value = values[parameterName].ToString();

        if (string.IsNullOrWhiteSpace(value))
        
            return _values.Contains(string.Empty);
        

        return _values.Contains(value.ToLower());
    

然后将约束的实例传递给您的 MapRoute 调用：

routes.MapRoute(null,
    "myaccount/monitor/category", // Matches
new  controller = "MyAccount", action = "Monitor", category = UrlParameter.Optional  ,
new  category = new FromValuesListConstraint ("overview", "projection", "history", string.Empty) 
        );

【参考方案2】：

您可以使用UrlParameter.Optional 来允许空值，也可以使用MapRoute method 的constraints 参数..

 routes.MapRoute(null,
                      "myaccount/monitor/category", // Matches
                      new  controller = "MyAccount", action = "Monitor", category = UrlParameter.Optional  ,
                      new  category = "overview|projection|history"
            );

【参考方案3】：

我认为您可能必须使用单独的路线：

routes.MapRoute("Monitor",
                      "myaccount/monitor", // Matches
                      new  controller = "MyAccount", action = "Monitor" 
            );

routes.MapRoute("MonitorHistory",
                      "myaccount/monitor/history", // Matches
                      new  controller = "MyAccount", action = "Monitor", category = "history" 
            );

routes.MapRoute("MonitorOverview",
                      "myaccount/monitor/overview", // Matches
                      new  controller = "MyAccount", action = "Monitor", category = "overview" 
            );

routes.MapRoute("MonitorProjection",
                      "myaccount/monitor/projection", // Matches
                      new  controller = "MyAccount", action = "Monitor", category = "projection" 
            );

或者，您可能想要执行以下操作：

routes.MapRoute("MonitorGlobal",
                      "myaccount/monitor/category", // Matches
                      new  controller = "MyAccount", action = "Monitor", category = string.Empty 
            );

然后在你的控制器中：

public ActionResult Monitor(string category)

    switch (category)
    
        case string.Empty:
            // do something
            break;

        case "overview":
            // do something
            break;

        // so on and so forth

        default:
            // no match, handle accordingly
            break;