I have this route values inside Global.asax
routes.MapRoute(
"Default", // Route name
"{controller}/{action}/{id}", // URL with parameters
new { controller = "Home", action = "Index", id = UrlParameter.Optional } // Parameter defaults
);
routes.MapRoute(
"Edit", // Route name
"Admin/{controller}/{action}/{id}", // URL with parameters
new { controller = "Edit", action = "Index", id = UrlParameter.Optional } // Parameter defaults
);
and I use this ActionLink method to call the Edit route
#Html.ActionLink("Edit", "Topic", "Edit", new { id = item.ID })
Now the result of the link generated is like this...
http://localhost:777/Admin/Topic?Length=4
How to use the route and target properly using the ActionLink method.
Thanks!
Use the correct overload of ActionLink to get the intended result
#Html.ActionLink("Edit", "Topic", "Edit", new { id = item.ID }, null)
The overload is ActionLink(string linkText, string actionName, string controllerName, object routeValues, object htmlAttributes)
Adding the null as null HTML attributes is necessary when you supply parameters to the action. Or if you actually needed to apply HTML Attributes to the link, you would use:
#Html.ActionLink("Edit", "Topic", "Edit", new { id = item.ID }, new { #class = "MyCustomCssClassName" } )
Related
I have set up the following routes so that I can use duplicate controller names (in different namespaces). This works fine but when I use html.actionlink from any controller it always includes the “CRUD” subfolder to the link.
var route1 = routes.MapRoute(
"CRUD",
"CRUD/{controller}/{action}/{id}",
new { action = "Index", id = UrlParameter.Optional }
);
route1.DataTokens["Namespaces"] = new string[] { "College.Controllers.CRUD" };
route1.DataTokens["UseNamespaceFallback"] = false;
var route2 = routes.MapRoute(
name: "Default",
url: "{controller}/{action}/{id}",
defaults: new { controller = "Home", action = "Index", id = UrlParameter.Optional },
namespaces: new[] { "College.Controllers" }
);
route2.DataTokens["Namespaces"] = new string[] { "College.Controllers" };
route2.DataTokens["UseNamespaceFallback"] = false;
So an html.actionlink in http://localhost/students/index looks like this
http://localhost/CRUD/students/Edit/1
What I want is this
http://localhost/students/Edit/1
I know I could fix this by specifying the route in the actionlink but I don’t want to do this because I want to re-scaffold in future and my changes would be overwritten.
The issue here is that your 2 routes are ambiguous when building the URL. There are basically 3 ways to fix this:
Add another route value to match that is not part of the URL.
Use RouteLink to specify the route by name (along with the other route value criteria to make it match).
Create a custom route to handle "constraining" it to a specific namespace or make a custom route constraint.
Since you explicitly stated the second option is unacceptable, here is an example of the first:
var route1 = routes.MapRoute(
"CRUD",
"CRUD/{controller}/{action}/{id}",
new { crud = "crud", action = "Index", id = UrlParameter.Optional }
);
route1.DataTokens["Namespaces"] = new string[] { "College.Controllers.CRUD" };
route1.DataTokens["UseNamespaceFallback"] = false;
var route2 = routes.MapRoute(
"Default",
"{controller}/{action}/{id}",
new { controller = "Home", action = "Index", id = UrlParameter.Optional }
);
route1.DataTokens["Namespaces"] = new string[] { "College.Controllers" };
route1.DataTokens["UseNamespaceFallback"] = false;
Now when you call #Html.ActionLink("Students", "Index", "Students", new { crud = (string)null }, null) it will not match the CRUD route, it will match the Default route.
To make it match the CRUD route, you have to explicitly add the route value to the ActionLink: #Html.ActionLink("Students", "Index", "Students", new { crud = "crud" }, null) or leave it out entirely: #Html.ActionLink("Students", "Index", "Students")
Constraining the Route
Here is an example of the 3rd option.
Unfortunately, we can't use a regular route constraint because Microsoft decided not to make the RequestContext object available in the IRouteConstraint interface. This means the namespace information about what controller the request is bound for is not available. So, we need to drop to a lower level and make a custom RouteBase class that implements the decorator pattern to wrap our existing Route class configuration.
This class simply checks to see if the namespace from the request matches a specific namespace before generating the URL.
public class NamespaceConstrainedRoute : RouteBase
{
private readonly string namespaceToMatch;
private readonly RouteBase innerRoute;
public NamespaceConstrainedRoute(string namespaceToMatch, RouteBase innerRoute)
{
if (string.IsNullOrEmpty(namespaceToMatch))
throw new ArgumentNullException("namespaceToMatch");
if (innerRoute == null)
throw new ArgumentNullException("innerRoute");
this.namespaceToMatch = namespaceToMatch;
this.innerRoute = innerRoute;
}
public override RouteData GetRouteData(HttpContextBase httpContext)
{
return innerRoute.GetRouteData(httpContext);
}
public override VirtualPathData GetVirtualPath(RequestContext requestContext, RouteValueDictionary values)
{
object namespaces;
if (requestContext.RouteData.DataTokens.TryGetValue("Namespaces", out namespaces)
&& namespaces is IList<string>
&& ((IList<string>)namespaces).Contains(namespaceToMatch))
{
return innerRoute.GetVirtualPath(requestContext, values);
}
// null indicates to try to match the next route in the route table
return null;
}
}
Usage
var route1 = new Route(
url: "CRUD/{controller}/{action}/{id}",
defaults: new RouteValueDictionary(new { action = "Index", id = UrlParameter.Optional }),
routeHandler: new MvcRouteHandler()
)
{
DataTokens = new RouteValueDictionary
{
{ "Namespaces", new string[] { "College.Controllers.CRUD" }},
{ "UseNamespaceFallback", false }
}
};
var route2 = new Route(
url: "{controller}/{action}/{id}",
defaults: new RouteValueDictionary(new { controller = "Home", action = "Index", id = UrlParameter.Optional }),
routeHandler: new MvcRouteHandler()
)
{
DataTokens = new RouteValueDictionary
{
{ "Namespaces", new string[] { "College.Controllers" }},
{ "UseNamespaceFallback", false }
}
};
routes.Add(
name: "CRUD",
item: new NamespaceConstrainedRoute(
namespaceToMatch: "College.Controllers.CRUD",
innerRoute: route1));
routes.Add(
name: "Default",
item: new NamespaceConstrainedRoute(
namespaceToMatch: "College.Controllers",
innerRoute: route2));
From this point, you could build your own MapRoute extension methods if you so choose to make the above configuration look cleaner.
I have 2 similar maproute requests but I'm trying to target different routes.
Basically I'm creating a picture project using ASP.NET MVC.
What I want is to have the URL as:
website.com/pictures/username
and
website.com/pictures/pictureid
I'm using this as the map routes atm. Hoped that the different signatures would be enough to distinguish which action i would need.
The pictures controller has the action methods as
ActionResult Index (string username) { ... }
ActionResult Index (long id) { ... }
routes.MapRoute(
"UsersPicturesRoute",
"Pictures/{username}",
new { controller = "Pictures", action = "Index", username = UrlParameter.Optional }
);
routes.MapRoute(
"SinglePictureRoute",
"Pictures/{id}",
new { controller = "Pictures", action = "Index", id = UrlParameter.Optional }
);
Is there a way to have this desired outcome?
You can change your RegisterRoutes in below sequence then you will get your required output
routes.MapRoute(
"SinglePictureRoute",
"Pictures/{id}",
new { controller = "Home", action = "abcd", id = UrlParameter.Optional },
new { id = #"\d+" } // Parameter constraints
);
routes.MapRoute(
"UsersPicturesRoute",
"Pictures/{username}",
new { controller = "Home", action = "abcTest", username = UrlParameter.Optional }
);
Global.asax route values
routes.MapRoute(
"Default", // Route name
"{controller}/{action}/{id}", // URL with parameters
new { controller = "Home", action = "Index", id = UrlParameter.Optional, filterDate = DateTime.Now.AddDays(-1), filterLevel = "INFO" } // Parameter defaults
);
Here's my actionlink
#Html.ActionLink(item.MachineName, "Machine", new { id = item.MachineName, filterLevel = "hello" }, null)
When the filterlevel is specified in the actionlink, it generates a url like this:
http://localhost:1781/LoggingDashboard/log/level/VERBOSE
Which is the same page as I am currently on. If I change the actionlink to use a property other than one that has a default value in the route table (yes, if I use filterDate it messes up too), it generates a link like this:
#Html.ActionLink(item.MachineName, "Machine", new { id = item.MachineName, foo = "bar" }, null)
http://localhost:1781/LoggingDashboard/log/Machine/C0UPSMON1?foo=bar
Is this behavior correct? Should I not be able to override the defaults set up in the route table? I have confirmed that if I remove the filterLevel default from the route table this works as I expect:
http://localhost:1781/LoggingDashboard/log/Machine/C0UPSMON1?filterLevel=VERBOSE
---EDIT---
sorry, here is the action
public ActionResult Machine(string id, DateTime filterDate, string filterLevel)
{
...
var model = new LogListViewModel { LogEntries = logEntries };
return View(model);
}
For the bounty I want to know how to override the "default" values that are specified in the routes from global.asax. i.e. I want to be able to override filterLevel and filterDate.
SLaks already said what is probably the best way to handle this problem. I don't know if this will work, but, what happens if you put this above the existing route (so there would be two in your global.asax now)?
routes.MapRoute(
"Filtered",
"{controller}/{action}/{id}?filterLevel={filterLevel}&filterDate={filterDate}",
new
{
controller = "Home",
action = "Index",
id = UrlParameter.Optional,
filterDate = DateTime.Now.AddDays(-1),
filterLevel = "INFO"
}
);
Also, it just occurred to me that the reason you don't like SLaks' solution is that it could be repetitive. Since you only have one route, these parameters probably indicate a global functionality, instead of an action-scoped functionality. You could fix this by adding the values in an action filter on each controller, or your could use a custom route handler to apply this globally. Either of these would allow you to take the filterLevel and filterDate fields out of your route definition and still get the scope you want. Then it should be no problem to pass the parameters in a querystring with Html.ActionLink().
To do this with the route handler, change your route definition to:
routes.Add(
new Route(
"{controller}/{action}/{id}",
new RouteValueDictionary(new{ controller = "Home", action = "Index", id = UrlParameter.Optional}),
new CustomRouteHandler()));
Your implementation of the route handler would be something like this:
public class CustomRouteHandler : IRouteHandler
{
public IHttpHandler GetHttpHandler(RequestContext requestContext)
{
var routeValues = requestContext.RouteData.Values;
if(!routeValues.ContainsKey("filterLevel"))
{
routeValues.Add("filterLevel","INFO");
}
if(!routeValues.ContainsKey("filterDate"))
{
routeValues.Add("filterDate", DateTime.Now.AddDays(-1));
}
var mvcRouteHandler = new MvcRouteHandler();
return (mvcRouteHandler as IRouteHandler).GetHttpHandler(requestContext);
}
}
I thought the defaults were always for entries defined in the URL, that you can't define a default to omit something not in the core URL, and anything else is passed as a querystring.
Interesting question.
HTH.
You should specify the default value in your method, like this:
public ActionResult Machine(string id, DateTime? filterDate = null, string filterLevel = "INFO")
{
filterDate = filterDate ?? DateTime.Now.AddDays(-1);
var model = new LogListViewModel { LogEntries = logEntries };
return View(model);
}
If there are default values that are not specified in the URL pattern, then you can't override them because they are used to determine route selection when matching routes for URL generation.
Let me give you an example. Suppose you had the following two routes.
routes.MapRoute(
"Default1", // Route name
"foo/{controller}/{action}/{id}", // URL with parameters
new { controller = "Home", action = "Index", id = UrlParameter.Optional
, filterLevel = "INFO" } // Parameter defaults
);
routes.MapRoute(
"Default2", // Route name
"bar/{controller}/{action}/{id}", // URL with parameters
new { controller = "Home", action = "Index", id = UrlParameter.Optional
, filterLevel = "DEBUG" } // Parameter defaults
);
Notice that there's a default value for "filterLevel", but there is no "{filterLevel}" parameter within the URL pattern.
Which URL should match when you do this?
#Html.ActionLink(item.MachineName, "Machine",
new { id = item.MachineName, filterLevel = "RANDOM" }, null)
If you could override the default value for filterLevel, then you'd expect both of the routes to match. But that doesn't make sense. In this case, neither matches because filterLevel isn't in the URL pattern and therefore the supplied filterLevel must match the default value. That way, you can do this:
#Html.ActionLink(item.MachineName, "Machine",
new { id = item.MachineName, filterLevel = "INFO" }, null)
//AND
#Html.ActionLink(item.MachineName, "Machine",
new { id = item.MachineName, filterLevel = "DEBUG" }, null)
to generate a URL for the first and second route respectively.
This confusion is why I always recommend to always use named routes.
I have defined a series of Routes in Global.asax.cs:
public static void RegisterRoutes(RouteCollection routes)
{
routes.IgnoreRoute("{resource}.axd/{*pathInfo}");
routes.MapRoute(null, "", // Only matches the empty URL (i.e. ~/)
new
{
controller = "Stream",
action = "Entry",
streamUrl = "Pages",
entryUrl = "HomePage"
}
);
routes.MapRoute(null, "{streamUrl}", // matches ~/Pages
new { controller = "Stream", action = "List" }
);
routes.MapRoute(null, "{streamUrl}/{entryUrl}", // matches ~/Pages/HomePage
new { controller = "Stream", action = "Entry" }
);
routes.MapRoute(
"Default", // Route name
"{controller}/{action}/{id}", // URL with parameters
new { controller = "Home", action = "Index", id = UrlParameter.Optional } // Parameter defaults
);
When I put in mydomain.com/ or mydomain.com/Pages/HomePage the route works exactly as I expect. So now I'm writing a partial view to generate a list of links. as a test I put this code in the partial view:
<ul>
<% foreach (var item in Model) { %>
<li id="<%:item.Text.Replace( " ", "-") %>">
//This works - link shows up in browser as mydomain.com/
<%: Html.RouteLink(item.Text, new{ streamUrl = "Pages", entryUrl = "HomePage" }) %>
//This does not work - link shows up as mydomain.com/Blog?entryUrl=BlogEntryOne
//instead of mydomain.com/Blog/BlogEntryOne
<%: Html.RouteLink(item.Text, new{ streamUrl = "Blog", entryUrl = "BlogEntryOne" }) %>
</li>
<% } %>
</ul>
I'm not sure why the entryUrl route value isn't being registered correctly. What am I missing?
I'm not terribly accustomed with MVC, but I think you should put your more specific route first, as in:
routes.MapRoute(null, "{streamUrl}/{entryUrl}", // matches ~/Pages/HomePage
new { controller = "Stream", action = "Entry" }
);
routes.MapRoute(null, "{streamUrl}", // matches ~/Pages
new { controller = "Stream", action = "List" }
);
I want only one controller action to handle all GETs. How can I map a route to do this?
routes.MapRoute("AllGETs",
"{*any}",
new { Controller = "YourController", Action = "YourAction" },
new { HttpMethod = new HttpMethodConstraint("GET") }
);
I actually ended up doing this, seemed to do what I needed:
routes.MapRoute(
// Route name
"Default",
// URL with parameters
"{controller}/{id}",
// Parameter defaults
new {controller = "Home", action = "GenericPostHandler", id = "" }
);