Force ListView to refresh or Invalidate in UWP

Question

I have a ListView with ItemTemplate. I want to bind one control background in ItemTemplate to 2 properties, one of properties is in ItemsSource and onother one is in my page. since UWP has no multibinding support, I bind it to one property in ItemSource and for another property in my page I want to handle it in my code behind.

<ListView >
<ListView.ItemTemplate>
          <DataTemplate>
                   <Border HorizontalAlignment="Stretch"
                           x:Name="myborder"
                           Padding="5,0,5,0"
                           Background="{Binding myProperty, Converter={StaticResource convertPropertyToBgColor },ConverterParameter=border}">
                                <StackPanel Padding="0,10,10,10"
                                            Background="{Binding myProperty, Converter={StaticResource convertPropertyToBgColor},ConverterParameter=stack}">
                                       <TextBlock Text="{Binding Text}">
                                </StackPanel>
                  </Border>
            </DataTemplate>
</ListView.ItemTemplate>
</ListView>

in the convertPropertyToBgColor I get the brush from Resources.

and in code behind when my second desired property is changed I Change My resources. so the brush I have used from resources get changed and because of that I want to call that converter again to refresh Background, I called updateLayout but it doesn't refresh my ListView and it doesn't call myConvereter again. How can I force ListView to recreate or refresh Items that it has made?

Answer 1

Generally you class should implement INotifyPropertyChanged, then once you change the property, usually in its setter you also call OnPropertyChanged event which will update your UI. There are plenty examples of that, here is one.

The other way, may be to call Bindings.Update(), but normally you probably should use the method above.

---

To make my comments clearer - something like this is possible:

<StackPanel Orientation="Horizontal" Background="{ThemeResource ApplicationPageBackgroundThemeBrush}">
    <ListView x:Name="myList" Width="200">
        <ListView.ItemTemplate>
            <DataTemplate>
                <Border HorizontalAlignment="Stretch"
                       x:Name="myborder"
                       Padding="5,0,5,0"
                       Background="{Binding Path=DataContext.MyProperty, ElementName=myList}">
                    <StackPanel Padding="0,10,10,10">
                        <TextBlock Text="{Binding}"/>
                    </StackPanel>
                </Border>
            </DataTemplate>
        </ListView.ItemTemplate>
        <x:String>Element 1</x:String>
        <x:String>Element 2</x:String>
        <x:String>Element 3</x:String>
    </ListView>
    <Button Content="Change" Click="Button_Click"/>
</StackPanel>

code behind:

public sealed partial class MainPage : Page, INotifyPropertyChanged
{
    public event PropertyChangedEventHandler PropertyChanged;
    void RaiseProperty(string name) => PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(name));

    private SolidColorBrush myPropety = new SolidColorBrush(Colors.Red);
    public SolidColorBrush MyProperty
    {
        get { return myPropety; }
        set { myPropety = value; RaiseProperty(nameof(MyProperty)); }
    }

    public MainPage()
    {
        this.InitializeComponent();
        this.DataContext = this;
    }
    private void Button_Click(object sender, RoutedEventArgs e) => MyProperty = new SolidColorBrush(Colors.Blue);
}