I'm trying to create an app which has the following pages:

• MainPage.xaml ( MainPage.xaml.cs)
• Name and suggestions.xaml ( Name and suggestions.xaml.cs)
• MainPageViewModel.cs

I want to check if the "participantsturn" is less than what the user chose from the picker on the main page. If it is then I want to add 1 to it until it is equal and then move on with the else. But now when I test it and pick more than 1 from the picker - it still skips the if and moves on to the else. Does anyone know how I can prevent this from happening/what part of the code I need to change? Thanks!

For the main page I have a picker from which the user can choose a number from 1-30:

<Picker x:Name="mypicker"
               Title="Choose number of participants" 
               ItemsSource="{Binding ItemCollection}"
               SelectedItem="{Binding SelectedItem}"
               SelectedIndex="{Binding SelectedItemIndex}"
               />

In the "MainPageViewModel" I have the following code:

public int SelectedItem { get; set; } 

        public ObservableCollection<int> ItemCollection { get; set; }
        public MainPageViewModel()
        { 
            ItemCollection = new ObservableCollection<int>();
            CreateCollection();
        }

        private void CreateCollection ()
        {
            var numList = Enumerable.Range(1, 30).ToList();
            ItemCollection = new ObservableCollection<int>(numList);
        }

In the "Name and suggestions.cs" page I have this code:

public partial class Name_and_suggestions : ContentPage
{
        public Name_and_suggestions()
        {
            InitializeComponent();

            this.BindingContext = new MainPageViewModel();
        }

        static int participantsturn = 1; 
}

And later:

if (participantsturn <= ((MainPageViewModel)this.BindingContext).SelectedItem)
{
   participantsturn  ;

}

I've tried something with the index, but I'm not sure how to do it right for this.

Here is updated code for how I navigate between the pages - on my main page I have a button which takes the user to the Name and Suggestions page when clicked:

<StackLayout Padding="50,50,50,0">
     <Button Text="Start" 
                x:Name="StartButton"
                Clicked="StartButton_Clicked"
                HeightRequest="50" 
                />
</StackLayout>

Here is the MainPage.xaml.cs code behind:

     private void StartButton_Clicked(object sender, EventArgs e)
        {

            if (mypicker.SelectedIndex >= 0)
            {
                Navigation.PushAsync(new Name_and_suggestions());
            }
            else
            {
                Console.WriteLine("Please choose the number of participants first");
            }
                
           
        }

CodePudding user response：

you need to pass the value when you navigate

var item = ((MainPageViewModel)BindingContext).SelectedItem
Navigation.PushAsync(new Name_and_suggestions(item));
    

then in the 2nd page, you need to modify it's constructor to accept the parameter

int player; 

public Name_and_suggestions(int player)
{
    InitializeComponent();

    this.player = player;

    ...
}

now the 2nd page has a class level variable player that contains the value chosen on the first page

CodePudding user response：

If you want to store the value, you could use Preferences in Xamarin.Essentials.

When you select a value in Picker, you could try the following code:

public int SelectedItem
{
    get
    {
        return selectedItem;
    }
    set
    {
        selectedItem = value;
        references.Set("PickerSelectedValue", value);
    }
}

And in another page, if you want to use this value:

int value = Preferences.Get("PickerSelectedValue", 1); // the second parameter is default value you want to set

For more info, you could refer to Xamarin.Essentials: Preferences

Hope it works for you.