ASP.NET MVC Route URL in Controller Constructor - asp.net

Question

I have a problem when trying to generate url in the controller constructor
private BreadCrumbItem breadCrumbItem;
public SummaryController()
{
this.breadCrumbItem = new BreadCrumbItem { Title = "Sommaire", Url = Url.RouteUrl(new { controller = "Summary", action = "Index" }) };
}
The problem is in Url.RouteUrl
Why i can't access this in the controller? Any way to fix this ?
Beacause otherwise i have to add the same code in all actions in this controller.
Thanks for help

Answer 1

If i understand your question right you want something like this:
public class SummaryController
{
public SummaryController()
{
}
private BreadCrumbItem _breadCrumbItem = null;
private BreadCrumbItem CrumbItem
{
get
{
if(_breadCrumbItem == null)
{
_breadCrumbItem = new BreadCrumbItem { Title = "Sommaire", Url = Url.RouteUrl(new { controller = "Summary", action = "Index" }) };
}
return _breadCrumbItem;
}
}
}
Now in each method you can simply use the CrumbItem and the first time it'll create the new BreadCrumItem and after that it'll just return you the created item each time it's called.

Answer 2

You can override the Initialize() method. The Url property is set once the base controller is initialized.
protected override void Initialize(RequestContext requestContext)
{
// the controller's UrlHelper is still null
base.Initialize(requestContext);
// the controller's UrlHelper is now ready to use!
var url = Url.RouteUrl(...);
}

Answer 3

You can access it in the controller but you can't access it in the constructor. This value isn't set at the time the constructor is called, obviously, because it it populated after the controller is created by the controller builder. Using the #middelpat solution to lazy load the property (creating it on first use in the current action) is a reasonable solution to the problem. The UrlHelper instance should be available in the controller at that point.

Answer 4

I think you need something like this answer:
https://stackoverflow.com/a/700357/637425
Quote:
If you just want to get the path to a certain action, use UrlHelper:
UrlHelper u = new UrlHelper(this.ControllerContext.RequestContext);
string url = u.Action("About", "Home", null);
if you want to create a
hyperlink:
string link = HtmlHelper.GenerateLink(this.ControllerContext.RequestContext,
System.Web.Routing.RouteTable.Routes, "My link", "Root", "About",
"Home", null, null);
Intellisense will give you the meaning of each of
the parameters.