C# Binding global static string to UWP Textblock

Question

everybody.

Does anyone knows how to bind global static string to UWP Textblock, with propertychange update in control?

I have tried a lot of things, such as:

Text="{Binding Path={local:AppSettings.StorageFolder}, Mode=OneWay}"
Text="{x:Bind Path=(local:AppSettings.StorageFolder), RelativeSource={RelativeSource Self}, Mode=OneWay}"

And none works. Always some error comes up, like: "Nested types are not supported and Value does not fall within the expected range"

I have managed to bind it to non static value in my class:

Text="{x:Bind viewModel.MyValue, Mode=OneWay}"

Any solution to this?

Thanx.

Answer 1

You simply can't bind to a static property in UWP the same way as you can in WPF. There is no x:Static markup extension available.

You have some options:

If the DataContext of the element is an instance of the type in which the static property is defined, you could bind to a static property as usual:

<TextBlock Text="{Binding MyStaticProperty}" />

public sealed partial class BlankPage1 : Page
{
    public BlankPage1()
    {
        this.InitializeComponent();
        this.DataContext = this;
    }

    public static string MyStaticProperty { get { return "Static..."; } }
}

If the static property is defined in another class, your best option would be to wrap the static property in a non-static one:

public sealed partial class BlankPage1 : Page
{
    public BlankPage1()
    {
        this.InitializeComponent();
        this.DataContext = this;
    }

    public static string MyWrapperProperty { get { return MyStaticClass.MyStaticProperty; } }
}

public static class MyStaticClass
{
    public static string MyStaticProperty { get { return "Static..."; } }
}

If you want property change notifications it makes no sense to bind to a static property at all because the source object of a property must implement the INotifyPropertyChanged interface for you to be able to refresh the target property dynamically by raising the PropertyChanged event.

You could still wrap the static property in a non-static one of a view model that implements the INotifyPropertyChanged interface:

public class ViewModel : INotifyPropertyChanged
{
    public string MyNonStaticProperty
    {
        get { return MyStaticClass.MyStaticProperty; }
        set { MyStaticClass.MyStaticProperty = value; NotifyPropertyChanged(); }
    }

    //...
}

public static class MyStaticClass
{
    public static string MyStaticProperty { get; set; }
}

You will obviosuly need to call NotifyPropertyChanged("MyNonStaticProperty") from the view model class whenever you want to refresh the target property in the view.

Answer 2

Currently in UWP when using x:Bind the end property (Ie at the end of the path) must be mutable / nonstatic. However you can reference static properties prior to that such as x:Bind local:MyClass.Singleton.NonstaticProperty.

The use of functions at the end of the x:Bind property path can also address this kind of challenge.