Shell navigation passing data not working

LarsNymand · August 24

When navigating to ItemDetailPage page with query paramenter "id" I get below error (it works without paramenter)
System.ArgumentException: 'unable to figure out route for: //items/details?id=3ca6c981-52d6-4875-ae74-2e20fd878b77
Parameter name: uri'

ItemDetailPage is not a part of the Shell hierarchy and therefore registered in the AppShell constructor:
Routing.RegisterRoute("//items/details", typeof(ItemDetailPage));

In the ItemDetailPage I have added QueryProperty:
[QueryProperty("ItemId", "id")]
public partial class ItemDetailPage : ContentPage

and added ItemId property to the class:
private string itemId;
public string ItemId { get { return itemId; } set { itemId = Uri.UnescapeDataString(value); } }

I navigate to the page by calling:
await Shell.Current.GoToAsync($"//items/details?id={item.Id}");

What am I missing to make this work?
If I remove the "id" parameter from the GoToAsync call it navigates, but without id.

Thank you in advance

LandLu · August 26

“//” means you want to use absolute routes to navigate: https://docs.microsoft.com/en-us/xamarin/xamarin-forms/app-fundamentals/shell/navigation#absolute-routes.
You'd better not consume it in your route's registration. Rename it like:

Routing.RegisterRoute("itemdetails", typeof(ItemDetailPage));

And you could successfully navigate to it with a parameter:

await Shell.Current.GoToAsync($"itemdetails?id={item.Id}");

LarsNymand · August 26

But the documentation says that absolute routes should work as well?
https://docs.microsoft.com/en-us/xamarin/xamarin-forms/app-fundamentals/shell/navigation#pass-data

async void OnCollectionViewSelectionChanged(object sender, SelectionChangedEventArgs e)
{
    string elephantName = (e.CurrentSelection.FirstOrDefault() as Animal).Name;
    await Shell.Current.GoToAsync($"//animals/elephants/elephantdetails?name={elephantName}");
}

LarsNymand · August 26

Might actually be this bug: https://github.com/xamarin/Xamarin.Forms/issues/6829

LandLu · August 27

Yes, you can use an absolute route. But you should not include the special identifier("//") in your route name when you registered it.
If you want to use absolute you can try

// Get the current absolute route
ShellNavigationState state = Shell.Current.CurrentState;
await Shell.Current.GoToAsync($"{state.Location}/itemdetails?id={item.Id}");

But you still need to modify your registration to the correct format as the sample: https://github.com/xamarin/xamarin-forms-samples/blob/master/UserInterface/Xaminals/Xaminals/AppShell.xaml.cs

LarsNymand · August 29

Hi LandLu,
I removed the leading "//" from my registration, but it didn't work before I added "Route" to my ShellContent in AppShell.xaml

<ShellContent Title="Items" Icon="tab_feed.png" Route="items" ContentTemplate="{DataTemplate local:ItemsPage}" />

Thank you for your help!

LandLu · August 29

If you want items to be your parent route you have to define it to your ShellContent.

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