Xamarin.Forms Shell Application: Pass parameter from one page to another page

Question

Hi. I'm Xamarin Forms Newbies. So far, I can navigate from one to another page. Here it is,

1. NoticeBoardGetPage.xaml
2. NoticeBoardEditPage.xaml

NoticeBoardGetPage.xaml navigate to NoticeBoardEditPage.xaml using below code,

 private async void OnSave(object obj)  
        {  
            await Shell.Current.GoToAsync(nameof(NoticeBoardEditPage));  
        }  

Next step,

I modify NoticeBoardEditPage.xaml to make it this page must receive parameter from NoticeBoardGetPage.xaml. Something like this,

 public partial class NoticeBoardEditPage : ContentPage  
    {        
        private string _Id;  
        public NoticeBoardEditPage(string Id)  
        {  
            InitializeComponent();  
            _Id = Id;  
  
            BindingContext = new NoticeBoardEditPageViewModel(_Id);  
        }  
    }  

NoticeBoardEditPageViewModel.cs

  public class NoticeBoardEditPageViewModel  
    {  
        public NoticeBoardEditPageViewModel(string Id)  
        { }  
  
  
  
    }  

Let say in NoticeBoardGetPage, I want send parameter named Id. Something like this,

 private async void OnSave(object obj)  
        {  
            string Id = "42";  
  
            //await Shell.Current.GoToAsync(nameof(NoticeBoardEditPage));  
        }  

How to modify,

await Shell.Current.GoToAsync(nameof(NoticeBoardEditPage));  

Please help

Answer 1

Hello,​

If you want to transfer ID to ViewModel of navigated page. You can use Process navigation data using a single method to achieve it.

Firstly, please add Id when you navigated page.

   private async void OnSave(object obj)  
            {  
                string Id = "42";  
                await Shell.Current.GoToAsync($"{nameof(NoticeBoardEditPage)}?Id={Id}");  
            }  

Then, please remove _Id in your NoticeBoardEditPageViewModel constructor like this code BindingContext = new NoticeBoardEditPageViewModel();

In the end. Navigation data can be received by implementing the IQueryAttributable interface on the NoticeBoardEditPageViewModel.

   public class NoticeBoardEditPageViewModel : IQueryAttributable  
       {  
           
           public NoticeBoardEditPageViewModel()  
           {  
                
           }  
     
           public void ApplyQueryAttributes(IDictionary<string, string> query)  
           {  
                
   //get the Id here.  
               string id = HttpUtility.UrlDecode(query["Id"]);  
                int ID= int.Parse(id);  
           }  
       }  

Best Regards,

Leon Lu

---

If the answer is the right solution, please click "Accept Answer" and kindly upvote it. If you have extra questions about this answer, please click "Comment".

Note: Please follow the steps in our documentation to enable e-mail notifications if you want to receive the related email notification for this thread.

Answer 2

Hi @Anonymous

It is stunning