guage wont refresh after update

[chris]

im following the binding example in RadControls Silverlight Courseware. ive attached the project..

when the timer is called and the stock quote is updated the gauge control does not reflect the change. any suggestion on what i might be doing wrong would greatly be appreciated

mainpage.xaml

<UserControl x:Class="Silverlightgauge.MainPage"
         xmlns:telerik="clr-namespace:Telerik.Windows.Controls;assembly=Telerik.Windows.Controls.Gauge"
         xmlns:abc="clr-namespace:Telerik.Windows;assembly=Telerik.Windows.Controls"   
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
        xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
        mc:Ignorable="d" d:DesignWidth="640" d:DesignHeight="480"
        Loaded="UserControl_Loaded" >

    <UserControl.Resources>
        <LinearGradientBrush x:Key="BackgroundBrush">
            <GradientStop Color="LightBlue" Offset="0.01" />
            <GradientStop Color="SkyBlue" Offset="0.02" />
            <GradientStop Color="SlateBlue" Offset="0.8" />
            <GradientStop Color="SkyBlue" Offset="0.99" />
            <GradientStop Color="LightBlue" Offset="1" />
        </LinearGradientBrush>
    </UserControl.Resources>

    <Grid x:Name="LayoutRoot">
        <telerik:RadGauge >
            <StackPanel Background="{StaticResource BackgroundBrush}"
                    HorizontalAlignment="Stretch">
                <StackPanel x:Name="spScales"   Orientation="Horizontal"
                        HorizontalAlignment="Center" Margin="10" />
            </StackPanel>
        </telerik:RadGauge>
    </Grid>
</UserControl>

code behind

Imports System.Windows.Controls
Imports System.Windows.Data
Imports System.Windows.Media
Imports System.Windows.Threading
Imports Telerik.Windows.Controls
Imports Telerik.Windows.Controls.Data
Imports Telerik.Windows.Controls.Gauges



Partial Public Class MainPage
    Inherits UserControl

    Private _random As New Random()
    Private _timer As New DispatcherTimer()
    Private _stocks As New Stocks()

    Public Sub New()
        InitializeComponent()
    End Sub


    Private Sub UserControl_Loaded(ByVal sender As Object, ByVal e As RoutedEventArgs)
        ' Create a stack panel for each stock and populate
        ' with text label and linear bar
        For Each stock As Stock In _stocks
            ' initialize a linear scale
            Dim scale As New LinearScale()
            scale.Min = 0
            scale.Max = 100
            scale.Width = 70
            ' add a linear bar, already bound to the stock
            scale.Indicators.Add(GetLinearBar(stock))
            ' create a label to display stock symbol
            Dim tb As New TextBlock()
            tb.FontWeight = System.Windows.FontWeights.Bold
            tb.Text = stock.Symbol
            ' initialize a stack panel to contain a text label
            ' and scale. Add the stack panel to the stack panel
            ' already in the xaml markup
            Dim stackPanel As New StackPanel()
            stackPanel.VerticalAlignment = VerticalAlignment.Stretch
            stackPanel.Children.Add(tb)
            stackPanel.Children.Add(scale)
            spScales.Children.Add(stackPanel)
        Next stock
        ' initialize and start a timer to update the stocks
        AddHandler _timer.Tick, AddressOf _timer_Tick
        _timer.Interval = New TimeSpan(0, 0, 0, 1)
        _timer.Start()
    End Sub

    Private Function GetLinearBar(ByVal stock As Stock) As LinearBar
        Dim linearBar As New LinearBar()
        linearBar.Value = stock.Quote
        linearBar.Background = New SolidColorBrush(GetRandomColor())
        linearBar.StartWidth = 0.1
        linearBar.EndWidth = 0.1
        linearBar.RelativeHeight = 0.9
        ' Bind linear bar to the Quote property of the data object.
        Dim binding As New Binding()
        binding.Source = stock
        binding.Path = New PropertyPath("Quote")
        binding.Mode = BindingMode.OneWay
       
        linearBar.SetBinding(linearBar.ValueProperty, binding)

        Return linearBar
    End Function

    Private Function GetRandomColor() As Color
        Return Color.FromArgb(150, CByte(_random.Next(0, 255)), _
        CByte(_random.Next(0, 255)), CByte(_random.Next(0, 255)))
    End Function

    Private Sub _timer_Tick(ByVal sender As Object, ByVal e As EventArgs)
        For Each stock As Stock In _stocks ' update the symbols
        
            stock.Quote = _random.Next(0, 100)
           
         
        Next stock
    End Sub
End Class

stock.vb

Imports System.ComponentModel

Public Class Stock
    Implements INotifyPropertyChanged

    Public Event PropertyChanged As PropertyChangedEventHandler
    Private _quote As Double
    Private _symbol As String
    Public Sub New(ByVal symbol As String, ByVal quote As Double)
        Me.Quote = quote
        Me.Symbol = symbol
    End Sub
    Public Property Quote() As Double
        Get
            Return _quote
        End Get
        Set(ByVal value As Double)
            _quote = value
            NotifyPropertyChanged("Quote")
        End Set
    End Property
    Public Property Symbol() As String
        Get
            Return _symbol
        End Get
        Set(ByVal value As String)
            _symbol = value
            NotifyPropertyChanged("Symbol")
        End Set
    End Property
    Private Sub NotifyPropertyChanged(ByVal propertyName As String)
        RaiseEvent PropertyChanged(Me, New PropertyChangedEventArgs(propertyName))
    End Sub

    Public Event PropertyChanged1(sender As Object, e As System.ComponentModel.PropertyChangedEventArgs) Implements System.ComponentModel.INotifyPropertyChanged.PropertyChanged
End Class


stocks.vb

Public Class Stocks
    Inherits List(Of Stock)
    Public Sub New()
        Dim symbols As List(Of String) = _
        New List(Of String)(New String() {"MSFT", "GOOG", "YHOO", "IBM", "AAPL"})
        Dim random As New Random()
        For Each symbol As String In symbols
            Me.Add(New Stock(symbol, random.Next(0, 100)))
        Next symbol
    End Sub
End Class





thanks

chris

[Ves]

Hi Chris,

The reason ins in the INotifyPropertyChanged implementation. There is an event PropertyChanged in the Stock class, and there is another one, named PropertyChanged1 which actually implements the INotifyPropertyChanged.PropertyChanged and this seems to lead this undesired behavior. You can strip all the gauge-related obejcts and bind the Text property of a TextBlock - you will still see the same behavior. Changing the Stock class fixes it. Here is the code:

Public Class Stock
    Implements INotifyPropertyChanged

    'Public Event PropertyChanged As PropertyChangedEventHandler
    Private _quote As Double
    Private _symbol As String
    Public Sub New(ByVal symbol As String, ByVal quote As Double)
        Me.Quote = quote
        Me.Symbol = symbol
    End Sub
    Public Property Quote() As Double
        Get
            Return _quote
        End Get
        Set(ByVal value As Double)
            _quote = value
            NotifyPropertyChanged("Quote")
        End Set
    End Property
    Public Property Symbol() As String
        Get
            Return _symbol
        End Get
        Set(ByVal value As String)
            _symbol = value
            NotifyPropertyChanged("Symbol")
        End Set
    End Property
    Private Sub NotifyPropertyChanged(ByVal propertyName As String)
        RaiseEvent PropertyChanged(Me, New PropertyChangedEventArgs(propertyName))
    End Sub

    Public Event PropertyChanged(sender As Object, e As System.ComponentModel.PropertyChangedEventArgs) Implements System.ComponentModel.INotifyPropertyChanged.PropertyChanged
End Class

Kind regards,
Ves
the Telerik team