Hi,

I would like to display gaze aware UserControls on a MainWindow depending on which button is clicked.

In order to do so, I have created a WPF program which display these UserControls on a grid called DisplayGrid. They are children of this grid depending of which button is activated. All Buttons are written ‘gaze aware’ in XAML code, which are MainWindow’s Buttons(MainButtons) and UserControls’ buttons.

There is my problem and not a simple one : on the first MainButton activation, UserControl displayed is not gaze aware. Button on this UserControl don’t react to my gaze.
Then I click on second MainButton, which display the second UserControl with its button, but this one is gaze aware.
The next MainButton activations will result as the first problem, UserControls buttons will be not gaze aware.

I don’t know from where the source problem is …
I have tried a lot of things, and i only have solution which is to recreate UserControls objets (VehicleControlsUC and VentilationControlsUC) just before apply function changeUC(param). This is not what i planned to do …

Maybe you could help me ?

MainWindow.xaml

<Window xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:eyeX="clr-namespace:EyeXFramework.Wpf;assembly=EyeXFramework"

        x:Class="blank_eye_tracking.MainWindow"
        Title="MainWindow"
        WindowStyle="None"
        ResizeMode="NoResize"  
        WindowState="Maximized"
        TextOptions.TextFormattingMode="Display"
        TextOptions.TextRenderingMode="Auto">

    <Window.Resources>
        <Style x:Key="EyeXGazeAwareElement"
               TargetType="FrameworkElement">
            <Setter Property="eyeX:Behavior.GazeAware" Value="True"/>
            <Setter Property="eyeX:Behavior.GazeAwareDelay" Value="0"/>
        </Style>

        <Style x:Key="MainButtonStyle"
               TargetType="Button"
               BasedOn="{StaticResource EyeXGazeAwareElement}">
            <Setter Property="Button.Background" Value="BlueViolet"/>
            <Style.Triggers>
                <Trigger Property="eyeX:Behavior.HasGaze" Value="True">
                    <Setter Property="Button.Background" Value="WhiteSmoke"/>
                </Trigger>
            </Style.Triggers>
        </Style>
    </Window.Resources>

    <Grid>
        <Grid.ColumnDefinitions>
            <ColumnDefinition Width="8*"/>
            <ColumnDefinition/>
        </Grid.ColumnDefinitions>
        <Grid Name="DisplayGrid"
              Grid.Column="0"
              Visibility="Visible">
        </Grid>
        <StackPanel Orientation="Vertical"
                    Grid.Column="1">
            <!-- These buttons are gaze aware on any time, no problem here -->
            <Button Name="Main_Button1"
                    Click="Main_Button1_Click"
                    Height="250"
                    Style="{StaticResource MainButtonStyle}"/>
            <Button Name="Main_Button2"
                    Click="Main_Button2_Click"
                    Height="250"
                    Style="{StaticResource MainButtonStyle}"/>
        </StackPanel>
    </Grid>
</Window>

MainWindow.xaml.cs

namespace blank_eye_tracking
{
    using System.Windows;
    using System.Windows.Controls;
    using System.Windows.Input;
    using System.Windows.Media.Animation;
    using System.Threading.Tasks;
    using System.Threading;
    using System;
    using System.Collections.Generic;
    using System.Windows.Media;

    /// <summary>
    /// Interaction logic for MainWindow.xaml
    /// </summary>
    public partial class MainWindow : Window
    {
        // ActualPage is DisplayGrid's actual child
        UserControl ActualPage;

        // Instanciate the UserControls as MainWindow's attributes (to use them on any time)
        VentilationControls VentilationUC = new VentilationControls();
        VehicleControls VehicleControlsUC = new VehicleControls();

        public MainWindow()
        {
            InitializeComponent();

            this.PreviewKeyDown += new KeyEventHandler(HandleEsc);
        }

        private void HandleEsc(object sender, KeyEventArgs e)
        {
            if (e.Key == Key.Escape)
            {
                this.Close();
            }
        }

        private void Main_Button1_Click(object sender, RoutedEventArgs e)
        {
            //VentilationControls VentilationUC = new VentilationControls();
            changeUC(VentilationUC);
        }

        private void Main_Button2_Click(object sender, RoutedEventArgs e)
        {
            //VehicleControls VehicleControlsUC = new VehicleControls();
            changeUC(VehicleControlsUC);
        }

        private void changeUC(UserControl UCPage)
        {
            // Initial time when no UserControl is displayed
            if (ActualPage == null)
            {
                DisplayGrid.Children.Add(UCPage);
                ActualPage = (UserControl)VisualTreeHelper.GetChild(DisplayGrid, 0);    // Add new UC as ActualPage
            }
            // Check if actual UserControl displayed is a different one 
            else if (!(ActualPage.Equals(UCPage)))
            {
                DisplayGrid.Children.Clear();                                           // Clear all DisplayGrid children
                DisplayGrid.Children.Add(UCPage);                                       // Add UserControl parameter as a child of DisplayGrid
                ActualPage = (UserControl)VisualTreeHelper.GetChild(DisplayGrid, 0);    // Refresh ActualPage to be used on "if-else if"
            }
        }
    }
}

VentilationControls.xaml

<UserControl x:Class="blank_eye_tracking.VentilationControls"
             xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
             xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" 
             xmlns:d="http://schemas.microsoft.com/expression/blend/2008" 
             xmlns:eyeX="clr-namespace:EyeXFramework.Wpf;assembly=EyeXFramework"
             mc:Ignorable="d">
    
    <UserControl.Resources>
        <Style x:Key="testbutton2"
               TargetType="Button">
            <Setter Property="Button.Background" Value="Pink"/>
            <Setter Property="eyeX:Behavior.GazeAware" Value="True"/>
            <Setter Property="eyeX:Behavior.GazeAwareDelay" Value="0"/>
            <Style.Triggers>
                <Trigger Property="eyeX:Behavior.HasGaze" Value="True">
                    <Setter Property="Button.Background" Value="Teal"/>
                </Trigger>
            </Style.Triggers>
        </Style>
    </UserControl.Resources>
    
    <Grid Margin="100 0 0 0">
        <Button Style="{StaticResource testbutton2}"
                Height="300"
                Width="300"/>
    </Grid>
</UserControl>

VehicleControls.xaml

<UserControl x:Class="blank_eye_tracking.VehicleControls"
             xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
             xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" 
             xmlns:d="http://schemas.microsoft.com/expression/blend/2008" 
             xmlns:eyeX="clr-namespace:EyeXFramework.Wpf;assembly=EyeXFramework"
             mc:Ignorable="d">
    
    <UserControl.Resources>
        <Style x:Key="testbutton1"
               TargetType="Button">
            <Setter Property="Button.Background" Value="Red"/>
            <Setter Property="eyeX:Behavior.GazeAware" Value="True"/>
            <Style.Triggers>
                <Trigger Property="eyeX:Behavior.HasGaze" Value="True">
                    <Setter Property="Button.Background" Value="Green"/>
                </Trigger>
            </Style.Triggers>
        </Style>
    </UserControl.Resources>

    <Grid Margin="0 0 100 0">
        <Button Style="{StaticResource testbutton1}"
                Height="300"
                Width="300"/>
    </Grid>
</UserControl>

VehicleControls.xaml.cs and VentilationControls.xaml.cs have the basic code inside.