CODEWITHSUNDEEP
c#uwp
LightGreen
LightGreen

Reputation: 83

PointerWheelChanged Event UWP

I have a GridView with enabled VerticalScroll. In MainPage.xaml.cs I intercepted the ScrollView's PointerWheelChanged Event.

In this PointerWheelChanged event, can you know whether the wheel scrolls up or down?

The code.

MainPage.xaml:

<Grid Background="{ThemeResource ApplicationPageBackgroundThemeBrush}">
    <TextBlock x:Name="txbNumber" HorizontalAlignment="Center" Margin="0,-230,0,0" TextWrapping="Wrap" VerticalAlignment="Center"/>
    <GridView x:Name="TestGrid" HorizontalAlignment="Center" Height="200" Margin="0" VerticalAlignment="Center" Width="200" Background="#FF44AF0D">
        <GridViewItem Content="item"/>
        <GridViewItem Content="item"/>
        <GridViewItem Content="item"/>
        <GridViewItem Content="item"/>
        <GridViewItem Content="item"/>
        <GridViewItem Content="item"/>
        <GridViewItem Content="item"/>
        <GridViewItem Content="item"/>
        <GridViewItem Content="item"/>
        <GridViewItem Content="item"/>
        <GridViewItem Content="item"/>
        <GridViewItem Content="item"/>
        <GridViewItem Content="item"/>
        <GridViewItem Content="item"/>
        <GridViewItem Content="item"/>
        <GridViewItem Content="item"/>
        <GridViewItem Content="item"/>
        <GridViewItem Content="item"/>
        <GridViewItem Content="item"/>
        <GridViewItem Content="item"/>
        <GridViewItem Content="item"/>
        <GridViewItem Content="item"/>
    </GridView>
</Grid>

MainPage.xaml.cs:

public sealed partial class MainPage : Page
{
    public MainPage()
    {
        this.InitializeComponent();
        TestGrid.AddHandler(UIElement.PointerWheelChangedEvent, new PointerEventHandler(OnPointerWheelChanged), true);
    }
    int number = 0;
    private void OnPointerWheelChanged(object sender, PointerRoutedEventArgs e)
    {
        txbNumber.Text = number.ToString();
        number += 1;
    }
}

Thank you in advance.

Upvotes: 2

Views: 1526

Answers (1)

earloc
earloc

Reputation: 2090

Examine the MouseWheelDelta property of the PointerRoutedEventArgs as follows:

private void WindowsPage_PointerWheelChanged(object sender, PointerRoutedEventArgs e)
{
  var delta = e.GetCurrentPoint((UIElement)sender).Properties.MouseWheelDelta;
}

Its value (int) indicates the direction the wheel has moved.

From the docs:

A positive value indicates that the wheel was rotated forward (away from the user) or tilted to the right; a negative value indicates that the wheel was rotated backward (toward the user) or tilted to the

Upvotes: 13

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