How to get value of DataModel field in code behind without using an Entry control on Xaml page in MAUI C#?

I'm new to C# and MAUI - so thank you for your help!

What I have:

I've created a very simple 2 page application that works great:

1. Page 1 uses a CollectionView to display a list of names defined by MyDataModel (FirstName, LastName, ID). If the user selects an item in the list, then the program navigates to a detail page for that item.
2. Page 2 displays the FirstName and LastName of the selected item using {Binding} to fill <Entry /> controls, plus a Submit button to commit any changes to my database. I do not want to use an <Entry /> to display the ID field to the user.

What I need:

On my details page: How do I reference the value of MyDataModel's ID if I don't have an <Entry /> for it?

For example:

MyDataModel MyRecord = new MyDataModel();
MyRecord.FirstName = FirstNameEntry.Text;   // Value from Xaml Entry
MyRecord.LastName = LastNameEntry.Text;     // Value from Xaml Entry
MyRecord.ID = __________;                   // How do I get this value without an Xaml Entry?

More detailed code below.

Data Model

Simple data model with 3 fields per record

public class MyDataModel
    {
        [PrimaryKey, AutoIncrement]
        public int ID { get; set; }
        public string FirstName { get; set; }
        public string LastName { get; set; }
    }

Collection View Page Code Behind

Collection View Selection Changed

private async void OnCollectionViewSelectionChanged(object sender, SelectionChangedEventArgs e)
    {
        if (e.CurrentSelection.FirstOrDefault() != null)
        {
            MyDataModel MySelectedItem = e.CurrentSelection.FirstOrDefault() as MyDataModel;
            await Navigation.PushAsync(new DetailPage
            {
                BindingContext = MySelectedItem 
            });
        }
    }

Detail Page Xaml

<Entry /> fields on Detail Page in Xaml

<Entry 
    x:Name="FirstNameEntry"
    Text="{Binding FirstName}" />

<Entry 
    x:Name="LastNameEntry"
    Text="{Binding LastName}" />

Detail Page Code Behind

How to access value of ID for this record without a Xaml <Entry /> for it?

public DetailPage()
    {
        InitializeComponent();
        BindingContext = this;
    }

private async void Submit_Button_Clicked(object sender, EventArgs e)
    {
        MyDataModel MyRecord = new MyDataModel();
        MyRecord.FirstName = FirstNameEntry.Text;
        MyRecord.LastName = LastNameEntry.Text;
        MyRecord.ID = ___How Do I Get ID Without Using an XAML Entry?___;   // int.Parse(IdEntry.Text);
        await SaveRecord(MyRecord);
    }

Thank you

pass the model via the constructor

await Navigation.PushAsync(new DetailPage(MySelectedItem));

then in DetailPage

private MyDataModel model;

public DetailPage(MyDataModel data)
{
    InitializeComponent();
    
    BindingContext = model = data;
}

private async void Submit_Button_Clicked(object sender, EventArgs e)
{
   // you are using data binding, so you do not
   // explicitly need to set any property values
   await SaveRecord(model);
}