Question

我有两种冲突的动作方法。基本上，我希望能够使用两个不同的路径来获取相同的视图，可以是项目的ID，也可以是项目的名称及其父项（项目可以在不同的父项中具有相同的名称）。搜索词可用于过滤列表。

例如......

Items/{action}/ParentName/ItemName
Items/{action}/1234-4321-1234-4321

以下是我的操作方法（还有Remove操作方法）...

// Method #1
public ActionResult Assign(string parentName, string itemName) { 
    // Logic to retrieve item's ID here...
    string itemId = ...;
    return RedirectToAction("Assign", "Items", new { itemId });
}

// Method #2
public ActionResult Assign(string itemId, string searchTerm, int? page) { ... }

以下是路线......

routes.MapRoute("AssignRemove",
                "Items/{action}/{itemId}",
                new { controller = "Items" }
                );

routes.MapRoute("AssignRemovePretty",
                "Items/{action}/{parentName}/{itemName}",
                new { controller = "Items" }
                );

我理解错误发生的原因，因为page参数可以为null，但我无法找出解决它的最佳方法。我的设计开始时很差吗？我已经考虑过扩展Method #1的签名以包含搜索参数并将Method #2中的逻辑移到他们都会调用的私有方法中，但我不相信这会实际解决歧义。

非常感谢任何帮助。

实际解决方案（基于Levi的回答）

我添加了以下课程......

public class RequireRouteValuesAttribute : ActionMethodSelectorAttribute {
    public RequireRouteValuesAttribute(string[] valueNames) {
        ValueNames = valueNames;
    }

    public override bool IsValidForRequest(ControllerContext controllerContext, MethodInfo methodInfo) {
        bool contains = false;
        foreach (var value in ValueNames) {
            contains = controllerContext.RequestContext.RouteData.Values.ContainsKey(value);
            if (!contains) break;
        }
        return contains;
    }

    public string[] ValueNames { get; private set; }
}

然后装饰动作方法......

[RequireRouteValues(new[] { "parentName", "itemName" })]
public ActionResult Assign(string parentName, string itemName) { ... }

[RequireRouteValues(new[] { "itemId" })]
public ActionResult Assign(string itemId) { ... }

Answer 1

MVC不支持仅基于签名的方法重载，因此这将失败：

public ActionResult MyMethod(int someInt) { /* ... */ }
public ActionResult MyMethod(string someString) { /* ... */ }

但是，支持基于属性的方法重载：

[RequireRequestValue("someInt")]
public ActionResult MyMethod(int someInt) { /* ... */ }

[RequireRequestValue("someString")]
public ActionResult MyMethod(string someString) { /* ... */ }

public class RequireRequestValueAttribute : ActionMethodSelectorAttribute {
    public RequireRequestValueAttribute(string valueName) {
        ValueName = valueName;
    }
    public override bool IsValidForRequest(ControllerContext controllerContext, MethodInfo methodInfo) {
        return (controllerContext.HttpContext.Request[ValueName] != null);
    }
    public string ValueName { get; private set; }
}

在上面的示例中，该属性只是说“如果请求中存在密钥 xxx ，则此方法匹配”。您还可以根据路径（controllerContext.RequestContext）中包含的信息进行过滤，如果这更适合您的目的。

Answer 2

路线{roleId}，{applicationName}和{roleName}中的参数与操作方法中的参数名称不匹配。我不知道这是否重要，但它更难以弄清楚你的意图是什么。

你的itemId是否符合可以通过正则表达式匹配的模式？如果是这样，那么您可以为路线添加约束，以便只有与模式匹配的url被识别为包含itemId。

如果你的itemId只包含数字，那么这将有效：

routes.MapRoute("AssignRemove",
                "Items/{action}/{itemId}",
                new { controller = "Items" },
                new { itemId = "\d+" }
                );

修改：您还可以向AssignRemovePretty路线添加约束，以便{parentName}和{itemName}都是必需的。

编辑2：此外，由于您的第一个操作只是重定向到第二个操作，因此您可以通过重命名第一个操作来消除一些歧义。

// Method #1
public ActionResult AssignRemovePretty(string parentName, string itemName) { 
    // Logic to retrieve item's ID here...
    string itemId = ...;
    return RedirectToAction("Assign", itemId);
}

// Method #2
public ActionResult Assign(string itemId, string searchTerm, int? page) { ... }

然后在路由中指定Action名称以强制调用正确的方法：

routes.MapRoute("AssignRemove",
                "Items/Assign/{itemId}",
                new { controller = "Items", action = "Assign" },
                new { itemId = "\d+" }
                );

routes.MapRoute("AssignRemovePretty",
                "Items/Assign/{parentName}/{itemName}",
                new { controller = "Items", action = "AssignRemovePretty" },
                new { parentName = "\w+", itemName = "\w+" }
                );

Answer 3

另一种方法是重命名其中一种方法，这样就不存在冲突。例如

// GET: /Movies/Delete/5
public ActionResult Delete(int id = 0)

// POST: /Movies/Delete/5
[HttpPost, ActionName("Delete")]
public ActionResult DeleteConfirmed(int id = 0)

请参阅http://www.asp.net/mvc/tutorials/getting-started-with-mvc3-part9-cs

Answer 4

最近我抓住机会改进了@Levi的答案，以支持我必须处理的更广泛的场景，例如：多参数支持，匹配其中任何一个（而不是全部），甚至不匹配它们。

这是我现在使用的属性：

/// <summary>
/// Flags an Action Method valid for any incoming request only if all, any or none of the given HTTP parameter(s) are set,
/// enabling the use of multiple Action Methods with the same name (and different signatures) within the same MVC Controller.
/// </summary>
public class RequireParameterAttribute : ActionMethodSelectorAttribute
{
    public RequireParameterAttribute(string parameterName) : this(new[] { parameterName })
    {
    }

    public RequireParameterAttribute(params string[] parameterNames)
    {
        IncludeGET = true;
        IncludePOST = true;
        IncludeCookies = false;
        Mode = MatchMode.All;
    }

    public override bool IsValidForRequest(ControllerContext controllerContext, MethodInfo methodInfo)
    {
        switch (Mode)
        {
            case MatchMode.All:
            default:
                return (
                    (IncludeGET && ParameterNames.All(p => controllerContext.HttpContext.Request.QueryString.AllKeys.Contains(p)))
                    || (IncludePOST && ParameterNames.All(p => controllerContext.HttpContext.Request.Form.AllKeys.Contains(p)))
                    || (IncludeCookies && ParameterNames.All(p => controllerContext.HttpContext.Request.Cookies.AllKeys.Contains(p)))
                    );
            case MatchMode.Any:
                return (
                    (IncludeGET && ParameterNames.Any(p => controllerContext.HttpContext.Request.QueryString.AllKeys.Contains(p)))
                    || (IncludePOST && ParameterNames.Any(p => controllerContext.HttpContext.Request.Form.AllKeys.Contains(p)))
                    || (IncludeCookies && ParameterNames.Any(p => controllerContext.HttpContext.Request.Cookies.AllKeys.Contains(p)))
                    );
            case MatchMode.None:
                return (
                    (!IncludeGET || !ParameterNames.Any(p => controllerContext.HttpContext.Request.QueryString.AllKeys.Contains(p)))
                    && (!IncludePOST || !ParameterNames.Any(p => controllerContext.HttpContext.Request.Form.AllKeys.Contains(p)))
                    && (!IncludeCookies || !ParameterNames.Any(p => controllerContext.HttpContext.Request.Cookies.AllKeys.Contains(p)))
                    );
        }
    }

    public string[] ParameterNames { get; private set; }

    /// <summary>
    /// Set it to TRUE to include GET (QueryStirng) parameters, FALSE to exclude them:
    /// default is TRUE.
    /// </summary>
    public bool IncludeGET { get; set; }

    /// <summary>
    /// Set it to TRUE to include POST (Form) parameters, FALSE to exclude them:
    /// default is TRUE.
    /// </summary>
    public bool IncludePOST { get; set; }

    /// <summary>
    /// Set it to TRUE to include parameters from Cookies, FALSE to exclude them:
    /// default is FALSE.
    /// </summary>
    public bool IncludeCookies { get; set; }

    /// <summary>
    /// Use MatchMode.All to invalidate the method unless all the given parameters are set (default).
    /// Use MatchMode.Any to invalidate the method unless any of the given parameters is set.
    /// Use MatchMode.None to invalidate the method unless none of the given parameters is set.
    /// </summary>
    public MatchMode Mode { get; set; }

    public enum MatchMode : int
    {
        All,
        Any,
        None
    }
}

有关更多信息和操作方法的示例，请查看我就此主题撰写的this blog post。

Answer 5

routes.MapRoute("AssignRemove",
                "Items/{parentName}/{itemName}",
                new { controller = "Items", action = "Assign" }
                );

考虑使用MVC Contribs测试路线库来测试你的路线

"Items/parentName/itemName".Route().ShouldMapTo<Items>(x => x.Assign("parentName", itemName));

ASP.NET MVC模糊的动作方法

5 个答案: