MasterDetailsView not showing master list items despite setting properties

Question

After following Microsoft's code for the MasterDetailsView control, the master list appears blank and doesn't show any items at all? Why has this happened and how can this be fixed?

MasterDetailPage.xaml

MasterDetailPage.xaml.cs

    public sealed partial class MasterDetailPage: Page
    {
        public MasterDetailPage()
        {    
            this.InitializeComponent();

        Binding myBinding = new Binding()
        {
            Source = Emails,
            Mode = BindingMode.OneWay
        };

        MyMasterDetailsView.SetBinding(MasterDetailsView.ItemsSourceProperty, myBinding);

            var emails = MyEmailManager.GetEmails();
            emails.ForEach(email => Emails.Add(email));
        }

        public ObservableCollection Emails = new ObservableCollection();

        public void OnXamlRendered(FrameworkElement control)
        {
            control.DataContext = this;
        }
    }

Email.cs

    public class Email
    {
        public string From { get; set; }
        public string Body { get; set; }
    }

    public class MyEmailManager
    {
        public static List GetEmails()
        {
            var MyEmails = new List
            {
                new Email
                {
                    From = "Steve Johnson",
                    Body = "Are you available for lunch tomorrow? A client would like to discuss a project with you."
                },
                new Email
                {
                    From = "Pete Davidson",
                    Body = "Don't forget the kids have their soccer game this Friday. We have to supply end of game snacks."
                },
                new Email
                {
                    From = "OneDrive",
                    Body = "Your new album.
You uploaded some photos to yuor OneDrive and automatically created an album for you."
                },
                new Email
                {
                    From = "Twitter",
                    Body = "Here are some people we think you might like to follow:
.@randomPerson
APersonYouMightKnow"
                }
            };

            return MyEmails;
        }
    }

Current result

Anran Zhang · Accepted Answer

From the code you provided, you did not assign a value to the Emails variable, please try the following code:

public MasterDetailPage()
{
    this.InitializeComponent();
    var emails = MyEmailManager.GetEmails();
    emails.ForEach(email => Emails.Add(email));
}

public ObservableCollection Emails = new ObservableCollection();

// other code

Due to the modification of the collection, you need to notify the UI to make changes, so it is recommended to use ObservableCollection instead of ICollection, and get the Email entry through MyEmailManager and add it to the collection.

In MasterDetailsView of XAML, binding Emails are required:

In WindowsCommunityToolkit, the complete Xaml and C# code can be viewed here

Thanks.

MasterDetailsView not showing master list items despite setting properties

Answers (1)

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