I need to pass a query string to a redirect. I know you can do this like so:
return RedirectToAction("Index", new { param1 = "hello" });
will go to /Index?param1=hello.
But I need to pass a parameter which has a hyphen in the name. Let's call it "data-param". Since hyphens aren't allowed in C# names, I can't do this in the above way. I know in some places in MVC, underscores are used to handle this, but that doesn't work here either, the underscore is passed to the query string as-is.
So my question is, how do I redirect to /Index?data-param=hello?
If you are trying to build a url, you can always slightly bypass the MVC routing and just pass the complete url in the old-fashioned way.
string dataParam="hello";
int otherParam=5;
return Redirect( String.Format("/Index?data-param={0}&data-param2={1}", dataParam, otherParam) );
If you are going outside of your own MVC application then you may not want RedirectToAction anyway unless you are redirecting to an action.
This works (I am using ASP.NET Core 3.1 and can't speak to earlier versions):
var params = new Dictionary<string, string>()
{
{ "data-param1", "hello" }
{ "data-param1", "2" }
};
return RedirectToAction("Index", params);
You can use Dictionary<string, object>() instead if you want, though you'll give up some control (e.g. false gets translated to "False" in the URL instead of "false"). And you should use nameof() for better maintainability:
var params = new Dictionary<string, object>()
{
{ "data-param1", "hello" }
{ "data-param2", 2 }
};
return RedirectToAction(nameof(Index), params);
Also note that this dictionary technique works with other methods too like RedirectToRoute().
Related
I am trying to get Url.Action() to return just the controller and action name.
I have a dictionary like so:
var dictionary = new Dictionary<string, string>()
{
{ "SiteUrl", config.Url },
{ "ResetPasswordLink", Url.Action("ResetPassword", new { token = e.Token }) }
};
config.Url returns www.mysite.com/foo/
Url.Action("ResetPassword", new { token = e.Token }) returns
/foo/account/resertpassword???token=blaBlaBla
The two are concatenated, returning www.mysite.com/foo/foo/......
This link obviously doesn't work. I can't remove "foo" from config.Url else other things break. I feel like this is something stupid and simple I am missing.
I could easily trim the /foo, but that doesn't seem quite right, or maybe I am over thinking it?
I've tried a bunch of different Url.Action() overloads and route values, but can't quite get what I need.
Any ideas?
Thanks.
I have seen this answer describing ASP.NET support for keyless (not valueless) parameters, like http://some.url?param1¶m2, and confirmed them to be viewable on Request.QueryString like:
var values = this.Request.QueryString.GetValues(null);
values.Any(o => o == "param1");
This is fine and dandy but now I want to generate urls like this. My first intuition was to use the RouteValueDictionary: routeValues parameter of Url.Action with null as a key:
#{
var dict = new RouteValueDictionary();
dict.Add(null, "param1");
dict.Add(null, "param2");
}
Very link, amaze
But apparently C# forbids nulls as dictionary keys because of reasons.
I have also tried the empty string as the key, but it results in a query string like: ?=param1,=param2 which contains 2 more equal signs that I want it to.
Of course I can string manipulate the heck out of my URL and add the ¶m1 part to the query string, but I was hoping for a concise solution.
You want to add the key values, but leaving the value null isn't allowed.
RouteValueDictionary ignores empty values
You could add a value like 1 for instance, but you lose your fine and dandy solution.
#{
var dict = new RouteValueDictionary();
dict.Add("param1",1);
}
Very link, amaze
For another solution you will have to write some custom code.
Since there's no built-in helper for this why don't you roll your own:
public static class UrlHelperExtensions
{
public static string MyAction(this UrlHelper urlHelper, string actionName, IList<string> parameters)
{
string url = urlHelper.Action(actionName);
if (parameters == null || !parameters.Any())
{
return url;
}
return string.Format("{0}?{1}", url, string.Join("&", parameters));
}
}
and then:
#{
var parameters = new List<string>();
parameters.Add("param1");
parameters.Add("param2");
}
#Url.MyAction("ActionName", parameters)
I have a method defined like this:
public ActionResult MatchedBusinesses(List<Business> businesses)
{
if (businesses != null)
{
return View(businesses);
}
return View("NoMatchFound");
}
Then, in my other method I have something similar to this one:
var list = results.AsEnumerable().OrderBy(b => Math.Abs(Convert.ToInt32(temp) - Convert.ToInt32(b.Zip))).Take(5).ToList();
return RedirectToAction("MatchedBusinesses", "Home", list);
The point is that, for the list variable I get the 5 entries that I select using the query. But, then I want to pass that result to my other method, which will be used in other method's view. The problem is, when I call the other method, the businesses parameter is always null. How can I solve the problem? Clearly, I'm not passing the parameter to my MatchedBusinesses method correctly. Any idea, how to solve the problem?
You are using the overload of RedirectToAction where the 3rd parameter is object routeValues. Internally the method uses reflection to build the route values based on the names and the ToString() values of the objects properties.
It works only for properties that are value types, but for properties that are complex types, including collections, it will not bind because (in your case) the value is a string "List<YourAssembly.Business>" and a string cannot be bound to a collection.
You need to persist the collection before redirecting (e.g. database, session, TempData) and then retrieve the collection in the action result.
For example
var list = results.AsEnumerable()....
TempData["results"] = list;
return RedirectToAction("MatchedBusinesses", "Home");
public ActionResult MatchedBusinesses()
{
List<Business> businesses = (List<Business>)TempData["results"];
}
but use TempData with caution (if the user refreshes the browser, the data will be lost). Its better to persist the information to the database with some key, and then pass the key as a route parameter to the MatchedBusinesses() method so that you can retrieve the data from the database.
Edit
What you're trying to do doesn't make much sense. You cannot, and should not, attempt to send large and/or complex objects, like a List, using Route. Instead you should use POST, or follow Stephen Muecke's suggestion in using TempData
However, here's how you can correctly send simple values using RouteValue
You pass parameters by using
return RedirectToAction("ActionName", "ControllerName",
new { paramName = paramValue });
Or if the target Action it's in the same controller
return RedirectToAction("ActionName", new { paramName = paramValue });
The parameter name, is optional. But using
return RedirectToAction("ActionName", new { paramName = paramValue });
Implies that the target action accepts a parameter with the name paramValue.
Here are all the overloads for RedirectToAction
http://msdn.microsoft.com/en-us/library/system.web.mvc.controller.redirecttoaction%28v=vs.118%29.aspx
Try wrapping your parameter in your return statement in a blank object variable like so:
return RedirectToAction("MatchedBusinesses", "Home", new { businesses = list });
All of the route values for an action have to be one parameter, so it's passed as an object, and then split into the various parameters of the receiving action. Even if you have only one param, it's still looking for an object to split.
In MVC 2 I have a RedirectToAction call which I need to pass all of the querystring parameters. Unfortunately I can only find a way to pass named querystring parameters is there a way of passing all querystring parameters regardless.
We have one named parameter, id but we just want to append all of the rest onto the end of the URL without setting them explicitly.
return RedirectToAction("index", "enquiry", new { id = enquiryCacheId.ToString()});
You cannot pass COMPLEX objects in URLs, so that kills the option of passing on Complex types in new { }.
One option what you are left with is to encode the querystring and then send that in 'id'. Say for examples, you have querystring as follows name=rami&gender=male. Then you can encode it with HttpUtility.UrlEncode(), then set it to id=[encoded string]. On the other action (retrieving side) you can get id value and then use HttpUtility.UrlDecode() to decode the string. Then finally you can use HttpUtility.ParseQueryString() to split the querystring into NameValueCollection.
If above suggestion is not what you are looking for then. you need to add all querystring parameters to new { } in the RedirectToAction(). If you want to customize it then you might need to go to ASP.Net MVC Source code #CodePlex and make your own builds (which I think not worthy for this kind of requirement).
I have an extension method that I use to modify the querystring of the current URL:
public static string ModifyQueryString(this UrlHelper helper, NameValueCollection updates, IEnumerable<string> removes)
{
var request = helper.RequestContext.HttpContext.Request;
var url = request.Url.AbsolutePath;
var query = HttpUtility.ParseQueryString(request.QueryString.ToString());
updates = updates ?? new NameValueCollection();
foreach (string key in updates.Keys)
{
query.Set(key, updates[key]);
}
removes = removes ?? new List<string>();
foreach (string param in removes)
{
query.Remove(param);
}
if (query.HasKeys())
{
return string.Format("{0}?{1}", url, query.ToString());
}
else
{
return url;
}
}
But, if you need to modify an arbitrary URL, it should be easy enough to modify. You would just need to add a parameter to accept an arbitrary URL, and then instead of getting the URL/querystring from the HttpContext, you just split the passed URL at ?. The rest of the code should work the same.
Disqus wants me to add an attribute called data-disqus-identifier to my links, but for obvious reasons, new { #data-disqus-identifier = "article" } gives me a syntax error.
Any idea what to do in these situations?
Thanks,
Rei
You can pass a Dictionary<string, object> with arbitrary string keys.
The syntax will be more verbose: new Dictionary<string, object> { { "data-disqus-identifier", "article" } }.
You may want to create an extension method or a static method on a static class with a short name that takes a smaller parameter set and returns the dictionary.
In MVC 3, if you use underscore _ instead of hyphens - in your property names then MVC will automatically convert them to hyphens in the resulting HTML. So, something like this should work for you:
new { data_disqus_identifier = "article" }