Hover/Unhover Issue | Infragistics Forums

285

Hover/Unhover Issue

Alycia posted over 14 years ago

I seem to have a flickering issue with a popup that shows up on hover. When the popup is open and the mouse goes over the popup, the popup flickers because its constantly trying to figure out which element its over and what data to pull. The problem is fixed when I remove the unhover event, but then when the mouse is off the map the popup is still open. Is there anyway to prevent the flickering and keep the unhover? I've been trying to figure out a way to set a variable that has a value when the mouse is over an element but that is null when its just over the background. Any ideas?

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Verified Answer

Offline Graham Murray posted over 14 years ago in reply to Alycia

Try:

AddHandler _popup.Child.MouseEnter, AddressOf Child_MouseEnter
AddHandler _popup.Child.MouseLeave, AddressOf Child_MouseLeave

And:

ElseIf _hoveredElement IsNot Nothing AndAlso _popup.DataContext IsNot _hoveredElement Then

This was verified using the Graham VB.NET compiler, so let me know if there are any errors.

-Graham

285

Alycia posted over 14 years ago in reply to Graham Murray

Thanks Graham. My project is done in vb.net (unfortunately) and after using a converter this is what it looks like.

Public Partial Class MainPage
    Inherits UserControl
    Public Sub New()
        InitializeComponent()
        _popup = thePopup
        _popup.Child.MouseEnter += New MouseEventHandler(AddressOf Child_MouseEnter)
        _popup.Child.MouseLeave += New MouseEventHandler(AddressOf Child_MouseLeave)
    End Sub

    Private Sub Child_MouseLeave(sender As Object, e As MouseEventArgs)
        _mouseOverPopup = False
        PossiblyHidePopup()
    End Sub

    Private Sub Child_MouseEnter(sender As Object, e As MouseEventArgs)
        _mouseOverPopup = True
    End Sub

    Private _popup As Popup
    Private _mouseOverPopup As Boolean
    Private _hoveredElement As MapElement

    Private Sub XamWebMap_ElementHover(sender As Object, e As Infragistics.Silverlight.Map.MapElementHoverEventArgs)
        _hoveredElement = e.Element
        TransitionPopup()
    End Sub

    Private Sub PossiblyHidePopup()
        'add a low priority item to the
        'queue to check if popup should be closed.
        Dispatcher.BeginInvoke(AddressOf TransitionPopup)
    End Sub

    Private Sub XamWebMap_ElementUnhover(sender As Object, e As Infragistics.Silverlight.Map.MapElementHoverEventArgs)
        _hoveredElement = Nothing
        PossiblyHidePopup()
    End Sub

    Private Sub TransitionPopup()
        If Not _mouseOverPopup AndAlso _hoveredElement Is Nothing Then
            _popup.IsOpen = False
            _popup.DataContext = Nothing
        ElseIf _hoveredElement IsNot Nothing AndAlso _popup.DataContext <> _hoveredElement Then
            Dim pos As Point = _hoveredElement.ActualSymbolOrigin
            pos = theMap.Viewport.RootCanvas.RenderTransform.Transform(pos)
            _popup.HorizontalOffset = pos.X
            _popup.VerticalOffset = pos.Y
            _popup.IsOpen = True
            _popup.DataContext = _hoveredElement
        End If
    End Sub
End Class

Silverlight seems to have problems with 2 sections of this code. These two lines:

_popup.Child.MouseEnter += New MouseEventHandler(AddressOf Child_MouseEnter)
_popup.Child.MouseLeave += New MouseEventHandler(AddressOf Child_MouseLeave)

The error says "Public Event MouseEnter(sender As Object, e As System.Windows.Input.MouseEventArgs) is an event and cannot be called directly. Use a 'RaiseEvent' statement to raise an event."

The other error is here:

ElseIf _hoveredElement IsNot Nothing AndAlso _popup.DataContext <> _hoveredElement Then...

The error says "Operator '<>' is not defined for types 'Object' and 'Infragistics.Silverlight.Map.MapElement'"

Do you have any suggestions?

Thanks!
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Offline Graham Murray posted over 14 years ago in reply to Graham Murray

see updated previous post, removed unused code.
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Suggested Answer

Offline Graham Murray posted over 14 years ago

This would be one way of approaching it:

 public partial class MainPage : UserControl
    {
        public MainPage()
        {
            InitializeComponent();
            _popup = thePopup;
            _popup.Child.MouseEnter += 
                new MouseEventHandler(Child_MouseEnter);
            _popup.Child.MouseLeave += 
                new MouseEventHandler(Child_MouseLeave);
         }

        void Child_MouseLeave(object sender, MouseEventArgs e)
        {
            _mouseOverPopup = false;
            PossiblyHidePopup();
        }

        void Child_MouseEnter(object sender, MouseEventArgs e)
        {
            _mouseOverPopup = true;
        }
  
        private Popup _popup;
        private bool _mouseOverPopup;
        private MapElement _hoveredElement;
       
        private void XamWebMap_ElementHover(
            object sender, 
            Infragistics.Silverlight.Map.MapElementHoverEventArgs e)
        {
            _hoveredElement = e.Element;
            TransitionPopup();
        }

        private void PossiblyHidePopup()
        {
            //add a low priority item to the 
            //queue to check if popup should be closed.
            Dispatcher.BeginInvoke(TransitionPopup);
        }

        private void XamWebMap_ElementUnhover(
            object sender, 
            Infragistics.Silverlight.Map.MapElementHoverEventArgs e)
        {
            _hoveredElement = null;
            PossiblyHidePopup();
        }

        private void TransitionPopup()
        {
            if (!_mouseOverPopup && _hoveredElement == null)
            {
                _popup.IsOpen = false;
                _popup.DataContext = null;
            }
            else if (_hoveredElement != null && 
                _popup.DataContext != _hoveredElement)
            {
                Point pos = _hoveredElement.ActualSymbolOrigin;
                pos = theMap.Viewport.RootCanvas
                    .RenderTransform.Transform(pos);
                _popup.HorizontalOffset = pos.X;
                _popup.VerticalOffset = pos.Y;
                _popup.IsOpen = true;
                _popup.DataContext = _hoveredElement;
            }
        }
    }

-Graham